content: /**
   * This file is part of Aion-Lightning <aion-lightning.org>.
   *
   *  Aion-Lightning is free software: you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation, either version 3 of the License, or
   *  (at your option) any later version.
   *
   *  Aion-Lightning is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details. *
   *  You should have received a copy of the GNU General Public License
   *  along with Aion-Lightning.
   *  If not, see <http://www.gnu.org/licenses/>.
   */
  
  /*
   * Written by Doug Lea with assistance from members of JCP JSR-166
   * Expert Group and released to the public domain, as explained at
   * http://creativecommons.org/publicdomain/zero/1.0/
   */
  package com.aionemu.commons.utils.internal.chmv8;
  
  import java.io.Serializable;
  import java.util.AbstractMap;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.ConcurrentModificationException;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.Hashtable;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.Set;
  import java.util.concurrent.ConcurrentMap;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.concurrent.atomic.AtomicReference;
  import java.util.concurrent.locks.AbstractQueuedSynchronizer;
  
  /**
   * A hash table supporting full concurrency of retrievals and high expected
   * concurrency for updates. This class obeys the same functional specification
   * as {@link java.util.Hashtable}, and includes versions of methods
   * corresponding to each method of {@code Hashtable}. However, even though all
   * operations are thread-safe, retrieval operations do <em>not</em> entail
   * locking, and there is <em>not</em> any support for locking the entire table
   * in a way that prevents all access. This class is fully inter-operable with
   * {@code Hashtable} in programs that rely on its thread safety but not on its
   * synchronization details.
   *
   * <p>
   * Retrieval operations (including {@code get}) generally do not block, so may
   * overlap with update operations (including {@code put} and {@code remove}).
   * Retrievals reflect the results of the most recently <em>completed</em> update
   * operations holding upon their onset. (More formally, an update operation for
   * a given key bears a <em>happens-before</em> relation with any (non-null)
   * retrieval for that key reporting the updated value.) For aggregate operations
   * such as {@code putAll} and {@code clear}, concurrent retrievals may reflect
   * insertion or removal of only some entries. Similarly, Iterators and
   * Enumerations return elements reflecting the state of the hash table at some
   * point at or since the creation of the iterator/enumeration. They do
   * <em>not</em> throw {@link ConcurrentModificationException}. However,
   * iterators are designed to be used by only one thread at a time. Bear in mind
   * that the results of aggregate status methods including {@code size}, {@code
   * isEmpty}, and {@code containsValue} are typically useful only when a map is
   * not undergoing concurrent updates in other threads. Otherwise the results of
   * these methods reflect transient states that may be adequate for monitoring or
   * estimation purposes, but not for program control.
   *
   * <p>
   * The table is dynamically expanded when there are too many collisions (i.e.,
   * keys that have distinct hash codes but fall into the same slot modulo the
   * table size), with the expected average effect of maintaining roughly two bins
   * per mapping (corresponding to a 0.75 load factor threshold for resizing).
   * There may be much variance around this average as mappings are added and
   * removed, but overall, this maintains a commonly accepted time/space tradeoff
   * for hash tables. However, resizing this or any other kind of hash table may
   * be a relatively slow operation. When possible, it is a good idea to provide a
   * size estimate as an optional {@code
   * initialCapacity} constructor argument. An additional optional
   * {@code loadFactor} constructor argument provides a further means of
   * customizing initial table capacity by specifying the table density to be used
   * in calculating the amount of space to allocate for the given number of
   * elements. Also, for compatibility with previous versions of this class,
   * constructors may optionally specify an expected {@code concurrencyLevel} as
   * an additional hint for internal sizing. Note that using many keys with
   * exactly the same {@code hashCode()} is a sure way to slow down performance of
   * any hash table.
   *
   * <p>
   * A {@link Set} projection of a ConcurrentHashMapV8 may be created (using
   * {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed (using
   * {@link #keySet(Object)} when only keys are of interest, and the mapped values
   * are (perhaps transiently) not used or all take the same mapping value.
   *
   * <p>
   * A ConcurrentHashMapV8 can be used as scalable frequency map (a form of
   * histogram or multiset) by using {@link LongAdder} values and initializing via
   * {@link #computeIfAbsent}. For example, to add a count to a
   * {@code ConcurrentHashMapV8<String,LongAdder> freqs}, you can use
   * {@code freqs.computeIfAbsent(k -> new
   * LongAdder()).increment();}
   *
   * <p>
   * This class and its views and iterators implement all of the <em>optional</em>
   * methods of the {@link Map} and {@link Iterator} interfaces.
   *
   * <p>
   * Like {@link Hashtable} but unlike {@link HashMap}, this class does
   * <em>not</em> allow {@code null} to be used as a key or value.
   *
   * <p>
   * ConcurrentHashMapV8s support sequential and parallel operations bulk
   * operations. (Parallel forms use the {@link ForkJoinPool#commonPool()}). Tasks
   * that may be used in other contexts are available in class
   * {@link ForkJoinTasks}. These operations are designed to be safely, and often
   * sensibly, applied even with maps that are being concurrently updated by other
   * threads; for example, when computing a snapshot summary of the values in a
   * shared registry. There are three kinds of operation, each with four forms,
   * accepting functions with Keys, Values, Entries, and (Key, Value) arguments
   * and/or return values. Because the elements of a ConcurrentHashMapV8 are not
   * ordered in any particular way, and may be processed in different orders in
   * different parallel executions, the correctness of supplied functions should
   * not depend on any ordering, or on any other objects or values that may
   * transiently change while computation is in progress; and except for forEach
   * actions, should ideally be side-effect-free.
   *
   * <ul>
   * <li>forEach: Perform a given action on each element. A variant form applies a
   * given transformation on each element before performing the action.</li>
   *
   * <li>search: Return the first available non-null result of applying a given
   * function on each element; skipping further search when a result is
   * found.</li>
   *
   * <li>reduce: Accumulate each element. The supplied reduction function cannot
   * rely on ordering (more formally, it should be both associative and
   * commutative). There are five variants:
   *
   * <ul>
   *
   * <li>Plain reductions. (There is not a form of this method for (key, value)
   * function arguments since there is no corresponding return type.)</li>
   *
   * <li>Mapped reductions that accumulate the results of a given function applied
   * to each element.</li>
   *
   * <li>Reductions to scalar doubles, longs, and ints, using a given basis
   * value.</li>
   *
   * </li>
   * </ul>
   * </ul>
   *
   * <p>
   * The concurrency properties of bulk operations follow from those of
   * ConcurrentHashMapV8: Any non-null result returned from {@code get(key)} and
   * related access methods bears a happens-before relation with the associated
   * insertion or update. The result of any bulk operation reflects the
   * composition of these per-element relations (but is not necessarily atomic
   * with respect to the map as a whole unless it is somehow known to be
   * quiescent). Conversely, because keys and values in the map are never null,
   * null serves as a reliable atomic indicator of the current lack of any result.
   * To maintain this property, null serves as an implicit basis for all
   * non-scalar reduction operations. For the double, long, and int versions, the
   * basis should be one that, when combined with any other value, returns that
   * other value (more formally, it should be the identity element for the
   * reduction). Most common reductions have these properties; for example,
   * computing a sum with basis 0 or a minimum with basis MAX_VALUE.
   *
   * <p>
   * Search and transformation functions provided as arguments should similarly
   * return null to indicate the lack of any result (in which case it is not
   * used). In the case of mapped reductions, this also enables transformations to
   * serve as filters, returning null (or, in the case of primitive
   * specializations, the identity basis) if the element should not be combined.
   * You can create compound transformations and filterings by composing them
   * yourself under this "null means there is nothing there now" rule before using
   * them in search or reduce operations.
   *
   * <p>
   * Methods accepting and/or returning Entry arguments maintain key-value
   * associations. They may be useful for example when finding the key for the
   * greatest value. Note that "plain" Entry arguments can be supplied using
   * {@code new
   * AbstractMap.SimpleEntry(k,v)}.
   *
   * <p>
   * Bulk operations may complete abruptly, throwing an exception encountered in
   * the application of a supplied function. Bear in mind when handling such
   * exceptions that other concurrently executing functions could also have thrown
   * exceptions, or would have done so if the first exception had not occurred.
   *
   * <p>
   * Speedups for parallel compared to sequential forms are common but not
   * guaranteed. Parallel operations involving brief functions on small maps may
   * execute more slowly than sequential forms if the underlying work to
   * parallelize the computation is more expensive than the computation itself.
   * Similarly, parallelization may not lead to much actual parallelism if all
   * processors are busy performing unrelated tasks.
   *
   * <p>
   * All arguments to all task methods must be non-null.
   *
   * <p>
   * <em>jsr166e note: During transition, this class uses nested functional
   * interfaces with different names but the same forms as those expected for
   * JDK8.</em>
   *
   * <p>
   * This class is a member of the
   * <a href="{@docRoot}/../technotes/guides/collections/index.html"> Java
   * Collections Framework</a>.
   *
   * @since 1.5
   * @author Doug Lea
   * @param <K>
   *            the type of keys maintained by this map
   * @param <V>
   *            the type of mapped values
   */
  public class ConcurrentHashMapV8<K, V> implements ConcurrentMap<K, V>, Serializable {
  
  	private static final long serialVersionUID = 7249069246763182397L;
  
  	/**
  	 * A partitionable iterator. A Spliterator can be traversed directly, but
  	 * can also be partitioned (before traversal) by creating another
  	 * Spliterator that covers a non-overlapping portion of the elements, and so
  	 * may be amenable to parallel execution.
  	 *
  	 * <p>
  	 * This interface exports a subset of expected JDK8 functionality.
  	 *
  	 * <p>
  	 * Sample usage: Here is one (of the several) ways to compute the sum of the
  	 * values held in a map using the ForkJoin framework. As illustrated here,
  	 * Spliterators are well suited to designs in which a task repeatedly splits
  	 * off half its work into forked subtasks until small enough to process
  	 * directly, and then joins these subtasks. Variants of this style can also
  	 * be used in completion-based designs.
  	 *
  	 * <pre>
  	 * {@code ConcurrentHashMapV8<String, Long> m = ...
  	 * // split as if have 8 * parallelism, for load balance
  	 * int n = m.size();
  	 * int p = aForkJoinPool.getParallelism() * 8;
  	 * int split = (n < p)? n : p;
  	 * long sum = aForkJoinPool.invoke(new SumValues(m.valueSpliterator(), split, null));
  	 * // ...
  	 * static class SumValues extends RecursiveTask<Long> {
  	 *   final Spliterator<Long> s;
  	 *   final int split;             // split while > 1
  	 *   final SumValues nextJoin;    // records forked subtasks to join
  	 *   SumValues(Spliterator<Long> s, int depth, SumValues nextJoin) {
  	 *     this.s = s; this.depth = depth; this.nextJoin = nextJoin;
  	 *   }
  	 *   public Long compute() {
  	 *     long sum = 0;
  	 *     SumValues subtasks = null; // fork subtasks
  	 *     for (int s = split >>> 1; s > 0; s >>>= 1)
  	 *       (subtasks = new SumValues(s.split(), s, subtasks)).fork();
  	 *     while (s.hasNext())        // directly process remaining elements
  	 *       sum += s.next();
  	 *     for (SumValues t = subtasks; t != null; t = t.nextJoin)
  	 *       sum += t.join();         // collect subtask results
  	 *     return sum;
  	 *   }
  	 * }
  	 * }
  	 * </pre>
  	 */
  	public static interface Spliterator<T> extends Iterator<T> {
  
  		/**
  		 * Returns a Spliterator covering approximately half of the elements,
  		 * guaranteed not to overlap with those subsequently returned by this
  		 * Spliterator. After invoking this method, the current Spliterator will
  		 * <em>not</em> produce any of the elements of the returned Spliterator,
  		 * but the two Spliterators together will produce all of the elements
  		 * that would have been produced by this Spliterator had this method not
  		 * been called. The exact number of elements produced by the returned
  		 * Spliterator is not guaranteed, and may be zero (i.e., with
  		 * {@code hasNext()} reporting {@code
  		 * false}) if this Spliterator cannot be further split.
  		 *
  		 * @return a Spliterator covering approximately half of the elements
  		 * @throws IllegalStateException
  		 *             if this Spliterator has already commenced traversing
  		 *             elements
  		 */
  		Spliterator<T> split();
  	}
  
  	/*
  	 * Overview:
  	 *
  	 * The primary design goal of this hash table is to maintain concurrent
  	 * readability (typically method get(), but also iterators and related
  	 * methods) while minimizing update contention. Secondary goals are to keep
  	 * space consumption about the same or better than java.util.HashMap, and to
  	 * support high initial insertion rates on an empty table by many threads.
  	 *
  	 * Each key-value mapping is held in a Node. Because Node key fields can
  	 * contain special values, they are defined using plain Object types (not
  	 * type "K"). This leads to a lot of explicit casting (and many explicit
  	 * warning suppressions to tell compilers not to complain about it). It also
  	 * allows some of the public methods to be factored into a smaller number of
  	 * internal methods (although sadly not so for the five variants of
  	 * put-related operations). The validation-based approach explained below
  	 * leads to a lot of code sprawl because retry-control precludes factoring
  	 * into smaller methods.
  	 *
  	 * The table is lazily initialized to a power-of-two size upon the first
  	 * insertion. Each bin in the table normally contains a list of Nodes (most
  	 * often, the list has only zero or one Node). Table accesses require
  	 * volatile/atomic reads, writes, and CASes. Because there is no other way
  	 * to arrange this without adding further indirections, we use intrinsics
  	 * (sun.misc.Unsafe) operations. The lists of nodes within bins are always
  	 * accurately traversable under volatile reads, so long as lookups check
  	 * hash code and non-nullness of value before checking key equality.
  	 *
  	 * We use the top (sign) bit of Node hash fields for control purposes -- it
  	 * is available anyway because of addressing constraints. Nodes with
  	 * negative hash fields are forwarding nodes to either TreeBins or resized
  	 * tables. The lower 31 bits of each normal Node's hash field contain a
  	 * transformation of the key's hash code.
  	 *
  	 * Insertion (via put or its variants) of the first node in an empty bin is
  	 * performed by just CASing it to the bin. This is by far the most common
  	 * case for put operations under most key/hash distributions. Other update
  	 * operations (insert, delete, and replace) require locks. We do not want to
  	 * waste the space required to associate a distinct lock object with each
  	 * bin, so instead use the first node of a bin list itself as a lock.
  	 * Locking support for these locks relies on builtin "synchronized"
  	 * monitors.
  	 *
  	 * Using the first node of a list as a lock does not by itself suffice
  	 * though: When a node is locked, any update must first validate that it is
  	 * still the first node after locking it, and retry if not. Because new
  	 * nodes are always appended to lists, once a node is first in a bin, it
  	 * remains first until deleted or the bin becomes invalidated (upon
  	 * resizing). However, operations that only conditionally update may inspect
  	 * nodes until the point of update. This is a converse of sorts to the lazy
  	 * locking technique described by Herlihy & Shavit.
  	 *
  	 * The main disadvantage of per-bin locks is that other update operations on
  	 * other nodes in a bin list protected by the same lock can stall, for
  	 * example when user equals() or mapping functions take a long time.
  	 * However, statistically, under random hash codes, this is not a common
  	 * problem. Ideally, the frequency of nodes in bins follows a Poisson
  	 * distribution (http://en.wikipedia.org/wiki/Poisson_distribution) with a
  	 * parameter of about 0.5 on average, given the resizing threshold of 0.75,
  	 * although with a large variance because of resizing granularity. Ignoring
  	 * variance, the expected occurrences of list size k are (exp(-0.5) *
  	 * pow(0.5, k) / factorial(k)). The first values are:
  	 *
  	 * 0: 0.60653066 1: 0.30326533 2: 0.07581633 3: 0.01263606 4: 0.00157952 5:
  	 * 0.00015795 6: 0.00001316 7: 0.00000094 8: 0.00000006 more: less than 1 in
  	 * ten million
  	 *
  	 * Lock contention probability for two threads accessing distinct elements
  	 * is roughly 1 / (8 * #elements) under random hashes.
  	 *
  	 * Actual hash code distributions encountered in practice sometimes deviate
  	 * significantly from uniform randomness. This includes the case when N >
  	 * (1<<30), so some keys MUST collide. Similarly for dumb or hostile usages
  	 * in which multiple keys are designed to have identical hash codes. Also,
  	 * although we guard against the worst effects of this (see method spread),
  	 * sets of hashes may differ only in bits that do not impact their bin index
  	 * for a given power-of-two mask. So we use a secondary strategy that
  	 * applies when the number of nodes in a bin exceeds a threshold, and at
  	 * least one of the keys implements Comparable. These TreeBins use a
  	 * balanced tree to hold nodes (a specialized form of red-black trees),
  	 * bounding search time to O(log N). Each search step in a TreeBin is around
  	 * twice as slow as in a regular list, but given that N cannot exceed
  	 * (1<<64) (before running out of addresses) this bounds search steps, lock
  	 * hold times, etc, to reasonable constants (roughly 100 nodes inspected per
  	 * operation worst case) so long as keys are Comparable (which is very
  	 * common -- String, Long, etc). TreeBin nodes (TreeNodes) also maintain the
  	 * same "next" traversal pointers as regular nodes, so can be traversed in
  	 * iterators in the same way.
  	 *
  	 * The table is resized when occupancy exceeds a percentage threshold
  	 * (nominally, 0.75, but see below). Any thread noticing an overfull bin may
  	 * assist in resizing after the initiating thread allocates and sets up the
  	 * replacement array. However, rather than stalling, these other threads may
  	 * proceed with insertions etc. The use of TreeBins shields us from the
  	 * worst case effects of overfilling while resizes are in progress. Resizing
  	 * proceeds by transferring bins, one by one, from the table to the next
  	 * table. To enable concurrency, the next table must be (incrementally)
  	 * prefilled with place-holders serving as reverse forwarders to the old
  	 * table. Because we are using power-of-two expansion, the elements from
  	 * each bin must either stay at same index, or move with a power of two
  	 * offset. We eliminate unnecessary node creation by catching cases where
  	 * old nodes can be reused because their next fields won't change. On
  	 * average, only about one-sixth of them need cloning when a table doubles.
  	 * The nodes they replace will be garbage collectable as soon as they are no
  	 * longer referenced by any reader thread that may be in the midst of
  	 * concurrently traversing table. Upon transfer, the old table bin contains
  	 * only a special forwarding node (with hash field "MOVED") that contains
  	 * the next table as its key. On encountering a forwarding node, access and
  	 * update operations restart, using the new table.
  	 *
  	 * Each bin transfer requires its bin lock, which can stall waiting for
  	 * locks while resizing. However, because other threads can join in and help
  	 * resize rather than contend for locks, average aggregate waits become
  	 * shorter as resizing progresses. The transfer operation must also ensure
  	 * that all accessible bins in both the old and new table are usable by any
  	 * traversal. This is arranged by proceeding from the last bin (table.length
  	 * - 1) up towards the first. Upon seeing a forwarding node, traversals (see
  	 * class Traverser) arrange to move to the new table without revisiting
  	 * nodes. However, to ensure that no intervening nodes are skipped, bin
  	 * splitting can only begin after the associated reverse-forwarders are in
  	 * place.
  	 *
  	 * The traversal scheme also applies to partial traversals of ranges of bins
  	 * (via an alternate Traverser constructor) to support partitioned aggregate
  	 * operations. Also, read-only operations give up if ever forwarded to a
  	 * null table, which provides support for shutdown-style clearing, which is
  	 * also not currently implemented.
  	 *
  	 * Lazy table initialization minimizes footprint until first use, and also
  	 * avoids resizings when the first operation is from a putAll, constructor
  	 * with map argument, or deserialization. These cases attempt to override
  	 * the initial capacity settings, but harmlessly fail to take effect in
  	 * cases of races.
  	 *
  	 * The element count is maintained using a specialization of LongAdder. We
  	 * need to incorporate a specialization rather than just use a LongAdder in
  	 * order to access implicit contention-sensing that leads to creation of
  	 * multiple CounterCells. The counter mechanics avoid contention on updates
  	 * but can encounter cache thrashing if read too frequently during
  	 * concurrent access. To avoid reading so often, resizing under contention
  	 * is attempted only upon adding to a bin already holding two or more nodes.
  	 * Under uniform hash distributions, the probability of this occurring at
  	 * threshold is around 13%, meaning that only about 1 in 8 puts check
  	 * threshold (and after resizing, many fewer do so). The bulk putAll
  	 * operation further reduces contention by only committing count updates
  	 * upon these size checks.
  	 *
  	 * Maintaining API and serialization compatibility with previous versions of
  	 * this class introduces several oddities. Mainly: We leave untouched but
  	 * unused constructor arguments refering to concurrencyLevel. We accept a
  	 * loadFactor constructor argument, but apply it only to initial table
  	 * capacity (which is the only time that we can guarantee to honor it.) We
  	 * also declare an unused "Segment" class that is instantiated in minimal
  	 * form only when serializing.
  	 */
  
  	/* ---------------- Constants -------------- */
  	/**
  	 * The largest possible table capacity. This value must be exactly 1<<30 to
  	 * stay within Java array allocation and indexing bounds for power of two
  	 * table sizes, and is further required because the top two bits of 32bit
  	 * hash fields are used for control purposes.
  	 */
  	private static final int MAXIMUM_CAPACITY = 1 << 30;
  	/**
  	 * The default initial table capacity. Must be a power of 2 (i.e., at least
  	 * 1) and at most MAXIMUM_CAPACITY.
  	 */
  	private static final int DEFAULT_CAPACITY = 16;
  	/**
  	 * The largest possible (non-power of two) array size. Needed by toArray and
  	 * related methods.
  	 */
  	static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
  	/**
  	 * The default concurrency level for this table. Unused but defined for
  	 * compatibility with previous versions of this class.
  	 */
  	private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
  	/**
  	 * The load factor for this table. Overrides of this value in constructors
  	 * affect only the initial table capacity. The actual floating point value
  	 * isn't normally used -- it is simpler to use expressions such as
  	 * {@code n - (n >>> 2)} for the associated resizing threshold.
  	 */
  	private static final float LOAD_FACTOR = 0.75f;
  	/**
  	 * The bin count threshold for using a tree rather than list for a bin. The
  	 * value reflects the approximate break-even point for using tree-based
  	 * operations.
  	 */
  	private static final int TREE_THRESHOLD = 8;
  	/**
  	 * Minimum number of rebinnings per transfer step. Ranges are subdivided to
  	 * allow multiple resizer threads. This value serves as a lower bound to
  	 * avoid resizers encountering excessive memory contention. The value should
  	 * be at least DEFAULT_CAPACITY.
  	 */
  	private static final int MIN_TRANSFER_STRIDE = 16;
  
  	/*
  	 * Encodings for Node hash fields. See above for explanation.
  	 */
  	static final int MOVED = 0x80000000; // hash field for forwarding nodes
  	static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
  	/**
  	 * Number of CPUS, to place bounds on some sizings
  	 */
  	static final int NCPU = Runtime.getRuntime().availableProcessors();
  
  	/* ---------------- Counters -------------- */
  	// Adapted from LongAdder and Striped64.
  	// See their internal docs for explanation.
  	// A padded cell for distributing counts
  	static final class CounterCell {
  
  		volatile long p0, p1, p2, p3, p4, p5, p6;
  		volatile long value;
  		volatile long q0, q1, q2, q3, q4, q5, q6;
  
  		CounterCell(long x) {
  			value = x;
  		}
  	}
  
  	/**
  	 * Holder for the thread-local hash code determining which CounterCell to
  	 * use. The code is initialized via the counterHashCodeGenerator, but may be
  	 * moved upon collisions.
  	 */
  	static final class CounterHashCode {
  
  		int code;
  	}
  
  	/**
  	 * Generates initial value for per-thread CounterHashCodes
  	 */
  	static final AtomicInteger counterHashCodeGenerator = new AtomicInteger();
  	/**
  	 * Increment for counterHashCodeGenerator. See class ThreadLocal for
  	 * explanation.
  	 */
  	static final int SEED_INCREMENT = 0x61c88647;
  	/**
  	 * Per-thread counter hash codes. Shared across all instances.
  	 */
  	static final ThreadLocal<CounterHashCode> threadCounterHashCode = new ThreadLocal<CounterHashCode>();
  
  	/* ---------------- Fields -------------- */
  	/**
  	 * The array of bins. Lazily initialized upon first insertion. Size is
  	 * always a power of two. Accessed directly by iterators.
  	 */
  	transient volatile Node<V>[] table;
  	/**
  	 * The next table to use; non-null only while resizing.
  	 */
  	private transient volatile Node<V>[] nextTable;
  	/**
  	 * Base counter value, used mainly when there is no contention, but also as
  	 * a fallback during table initialization races. Updated via CAS.
  	 */
  	private transient volatile long baseCount;
  	/**
  	 * Table initialization and resizing control. When negative, the table is
  	 * being initialized or resized: -1 for initialization, else -(1 + the
  	 * number of active resizing threads). Otherwise, when table is null, holds
  	 * the initial table size to use upon creation, or 0 for default. After
  	 * initialization, holds the next element count value upon which to resize
  	 * the table.
  	 */
  	private transient volatile int sizeCtl;
  	/**
  	 * The next table index (plus one) to split while resizing.
  	 */
  	private transient volatile int transferIndex;
  	/**
  	 * The least available table index to split while resizing.
  	 */
  	private transient volatile int transferOrigin;
  	/**
  	 * Spinlock (locked via CAS) used when resizing and/or creating Cells.
  	 */
  	private transient volatile int counterBusy;
  	/**
  	 * Table of counter cells. When non-null, size is a power of 2.
  	 */
  	private transient volatile CounterCell[] counterCells;
  	// views
  	private transient KeySetView<K, V> keySet;
  	private transient ValuesView<K, V> values;
  	private transient EntrySetView<K, V> entrySet;
  	/**
  	 * For serialization compatibility. Null unless serialized; see below
  	 */
  	private Segment<K, V>[] segments;
  
  	/* ---------------- Table element access -------------- */
  
  	/*
  	 * Volatile access methods are used for table elements as well as elements
  	 * of in-progress next table while resizing. Uses are null checked by
  	 * callers, and implicitly bounds-checked, relying on the invariants that
  	 * tab arrays have non-zero size, and all indices are masked with
  	 * (tab.length - 1) which is never negative and always less than length.
  	 * Note that, to be correct wrt arbitrary concurrency errors by users,
  	 * bounds checks must operate on local variables, which accounts for some
  	 * odd-looking inline assignments below.
  	 */
  	@SuppressWarnings("unchecked")
  	static final <V> Node<V> tabAt(Node<V>[] tab, int i) { // used by Traverser
  		return (Node<V>) U.getObjectVolatile(tab, ((long) i << ASHIFT) + ABASE);
  	}
  
  	private static final <V> boolean casTabAt(Node<V>[] tab, int i, Node<V> c, Node<V> v) {
  		return U.compareAndSwapObject(tab, ((long) i << ASHIFT) + ABASE, c, v);
  	}
  
  	private static final <V> void setTabAt(Node<V>[] tab, int i, Node<V> v) {
  		U.putObjectVolatile(tab, ((long) i << ASHIFT) + ABASE, v);
  	}
  
  	/* ---------------- Nodes -------------- */
  	/**
  	 * Key-value entry. Note that this is never exported out as a user-visible
  	 * Map.Entry (see MapEntry below). Nodes with a hash field of MOVED are
  	 * special, and do not contain user keys or values. Otherwise, keys are
  	 * never null, and null val fields indicate that a node is in the process of
  	 * being deleted or created. For purposes of read-only access, a key may be
  	 * read before a val, but can only be used after checking val to be
  	 * non-null.
  	 */
  	static class Node<V> {
  
  		final int hash;
  		final Object key;
  		volatile V val;
  		volatile Node<V> next;
  
  		Node(int hash, Object key, V val, Node<V> next) {
  			this.hash = hash;
  			this.key = key;
  			this.val = val;
  			this.next = next;
  		}
  	}
  
  	/* ---------------- TreeBins -------------- */
  	/**
  	 * Nodes for use in TreeBins
  	 */
  	static final class TreeNode<V> extends Node<V> {
  
  		TreeNode<V> parent; // red-black tree links
  		TreeNode<V> left;
  		TreeNode<V> right;
  		TreeNode<V> prev; // needed to unlink next upon deletion
  		boolean red;
  
  		TreeNode(int hash, Object key, V val, Node<V> next, TreeNode<V> parent) {
  			super(hash, key, val, next);
  			this.parent = parent;
  		}
  	}
  
  	/**
  	 * A specialized form of red-black tree for use in bins whose size exceeds a
  	 * threshold.
  	 *
  	 * TreeBins use a special form of comparison for search and related
  	 * operations (which is the main reason we cannot use existing collections
  	 * such as TreeMaps). TreeBins contain Comparable elements, but may contain
  	 * others, as well as elements that are Comparable but not necessarily
  	 * Comparable<T> for the same T, so we cannot invoke compareTo among them.
  	 * To handle this, the tree is ordered primarily by hash value, then by
  	 * getClass().getName() order, and then by Comparator order among elements
  	 * of the same class. On lookup at a node, if elements are not comparable or
  	 * compare as 0, both left and right children may need to be searched in the
  	 * case of tied hash values. (This corresponds to the full list search that
  	 * would be necessary if all elements were non-Comparable and had tied
  	 * hashes.) The red-black balancing code is updated from pre-jdk-collections
  	 * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java) based in
  	 * turn on Cormen, Leiserson, and Rivest "Introduction to Algorithms" (CLR).
  	 *
  	 * TreeBins also maintain a separate locking discipline than regular bins.
  	 * Because they are forwarded via special MOVED nodes at bin heads (which
  	 * can never change once established), we cannot use those nodes as locks.
  	 * Instead, TreeBin extends AbstractQueuedSynchronizer to support a simple
  	 * form of read-write lock. For update operations and table validation, the
  	 * exclusive form of lock behaves in the same way as bin-head locks.
  	 * However, lookups use shared read-lock mechanics to allow multiple readers
  	 * in the absence of writers. Additionally, these lookups do not ever block:
  	 * While the lock is not available, they proceed along the slow traversal
  	 * path (via next-pointers) until the lock becomes available or the list is
  	 * exhausted, whichever comes first. (These cases are not fast, but maximize
  	 * aggregate expected throughput.) The AQS mechanics for doing this are
  	 * straightforward. The lock state is held as AQS getState(). Read counts
  	 * are negative; the write count (1) is positive. There are no signalling
  	 * preferences among readers and writers. Since we don't need to export full
  	 * Lock API, we just override the minimal AQS methods and use them directly.
  	 */
  	static final class TreeBin<V> extends AbstractQueuedSynchronizer {
  
  		private static final long serialVersionUID = 2249069246763182397L;
  		transient TreeNode<V> root; // root of tree
  		transient TreeNode<V> first; // head of next-pointer list
  
  		/* AQS overrides */
  		@Override
  		public final boolean isHeldExclusively() {
  			return getState() > 0;
  		}
  
  		@Override
  		public final boolean tryAcquire(int ignore) {
  			if (compareAndSetState(0, 1)) {
  				setExclusiveOwnerThread(Thread.currentThread());
  				return true;
  			}
  			return false;
  		}
  
  		@Override
  		public final boolean tryRelease(int ignore) {
  			setExclusiveOwnerThread(null);
  			setState(0);
  			return true;
  		}
  
  		@Override
  		public final int tryAcquireShared(int ignore) {
  			for (int c;;) {
  				if ((c = getState()) > 0)
  					return -1;
  				if (compareAndSetState(c, c - 1))
  					return 1;
  			}
  		}
  
  		@Override
  		public final boolean tryReleaseShared(int ignore) {
  			int c;
  			do {
  			} while (!compareAndSetState(c = getState(), c + 1));
  			return c == -1;
  		}
  
  		/**
  		 * From CLR
  		 */
  		private void rotateLeft(TreeNode<V> p) {
  			if (p != null) {
  				TreeNode<V> r = p.right, pp, rl;
  				if ((rl = p.right = r.left) != null)
  					rl.parent = p;
  				if ((pp = r.parent = p.parent) == null)
  					root = r;
  				else if (pp.left == p)
  					pp.left = r;
  				else
  					pp.right = r;
  				r.left = p;
  				p.parent = r;
  			}
  		}
  
  		/**
  		 * From CLR
  		 */
  		private void rotateRight(TreeNode<V> p) {
  			if (p != null) {
  				TreeNode<V> l = p.left, pp, lr;
  				if ((lr = p.left = l.right) != null)
  					lr.parent = p;
  				if ((pp = l.parent = p.parent) == null)
  					root = l;
  				else if (pp.right == p)
  					pp.right = l;
  				else
  					pp.left = l;
  				l.right = p;
  				p.parent = l;
  			}
  		}
  
  		/**
  		 * Returns the TreeNode (or null if not found) for the given key
  		 * starting at given root.
  		 */
  		@SuppressWarnings("unchecked")
  		final TreeNode<V> getTreeNode(int h, Object k, TreeNode<V> p) {
  			Class<?> c = k.getClass();
  			while (p != null) {
  				int dir, ph;
  				Object pk;
  				Class<?> pc;
  				if ((ph = p.hash) == h) {
  					if ((pk = p.key) == k || k.equals(pk))
  						return p;
  					if (c != (pc = pk.getClass()) || !(k instanceof Comparable)
  							|| (dir = ((Comparable<Comparable<?>>) k).compareTo((Comparable<?>) pk)) == 0) {
  						if ((dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName())) == 0) {
  							TreeNode<V> r = null, pl, pr; // check both sides
  							if ((pr = p.right) != null && h >= pr.hash && (r = getTreeNode(h, k, pr)) != null)
  								return r;
  							else if ((pl = p.left) != null && h <= pl.hash)
  								dir = -1;
  							else // nothing there
  								return null;
  						}
  					}
  				} else
  					dir = (h < ph) ? -1 : 1;
  				p = (dir > 0) ? p.right : p.left;
  			}
  			return null;
  		}
  
  		/**
  		 * Wrapper for getTreeNode used by CHM.get. Tries to obtain read-lock to
  		 * call getTreeNode, but during failure to get lock, searches along next
  		 * links.
  		 */
  		final V getValue(int h, Object k) {
  			Node<V> r = null;
  			int c = getState(); // Must read lock state first
  			for (Node<V> e = first; e != null; e = e.next) {
  				if (c <= 0 && compareAndSetState(c, c - 1)) {
  					try {
  						r = getTreeNode(h, k, root);
  					} finally {
  						releaseShared(0);
  					}
  					break;
  				} else if (e.hash == h && k.equals(e.key)) {
  					r = e;
  					break;
  				} else
  					c = getState();
  			}
  			return r == null ? null : r.val;
  		}
  
  		/**
  		 * Finds or adds a node.
  		 *
  		 * @return null if added
  		 */
  		@SuppressWarnings("unchecked")
  		final TreeNode<V> putTreeNode(int h, Object k, V v) {
  			Class<?> c = k.getClass();
  			TreeNode<V> pp = root, p = null;
  			int dir = 0;
  			while (pp != null) { // find existing node or leaf to insert at
  				int ph;
  				Object pk;
  				Class<?> pc;
  				p = pp;
  				if ((ph = p.hash) == h) {
  					if ((pk = p.key) == k || k.equals(pk))
  						return p;
  					if (c != (pc = pk.getClass()) || !(k instanceof Comparable)
  							|| (dir = ((Comparable<Comparable<?>>) k).compareTo((Comparable<?>) pk)) == 0) {
  						TreeNode<V> s = null, r = null, pr;
  						if ((dir = (c == pc) ? 0 : c.getName().compareTo(pc.getName())) == 0) {
  							if ((pr = p.right) != null && h >= pr.hash && (r = getTreeNode(h, k, pr)) != null)
  								return r;
  							else // continue left
  								dir = -1;
  						} else if ((pr = p.right) != null && h >= pr.hash)
  							s = pr;
  						if (s != null && (r = getTreeNode(h, k, s)) != null)
  							return r;
  					}
  				} else
  					dir = (h < ph) ? -1 : 1;
  				pp = (dir > 0) ? p.right : p.left;
  			}
  
  			TreeNode<V> f = first;
  			TreeNode<V> x = first = new TreeNode<V>(h, k, v, f, p);
  			if (p == null)
  				root = x;
  			else { // attach and rebalance; adapted from CLR
  				TreeNode<V> xp, xpp;
  				if (f != null)
  					f.prev = x;
  				if (dir <= 0)
  					p.left = x;
  				else
  					p.right = x;
  				x.red = true;
  				while ((xp = x.parent) != null && xp.red && (xpp = xp.parent) != null) {
  					TreeNode<V> xppl = xpp.left;
  					if (xp == xppl) {
  						TreeNode<V> y = xpp.right;
  						if (y != null && y.red) {
  							y.red = false;
  							xp.red = false;
  							xpp.red = true;
  							x = xpp;
  						} else {
  							if (x == xp.right) {
  								rotateLeft(x = xp);
  								xpp = (xp = x.parent) == null ? null : xp.parent;
  							}
  							if (xp != null) {
  								xp.red = false;
  								if (xpp != null) {
  									xpp.red = true;
  									rotateRight(xpp);
  								}
  							}
  						}
  					} else {
  						TreeNode<V> y = xppl;
  						if (y != null && y.red) {
  							y.red = false;
  							xp.red = false;
  							xpp.red = true;
  							x = xpp;
  						} else {
  							if (x == xp.left) {
  								rotateRight(x = xp);
  								xpp = (xp = x.parent) == null ? null : xp.parent;
  							}
  							if (xp != null) {
  								xp.red = false;
  								if (xpp != null) {
  									xpp.red = true;
  									rotateLeft(xpp);
  								}
  							}
  						}
  					}
  				}
  				TreeNode<V> r = root;
  				if (r != null && r.red)
  					r.red = false;
  			}
  			return null;
  		}
  
  		/**
  		 * Removes the given node, that must be present before this call. This
  		 * is messier than typical red-black deletion code because we cannot
  		 * swap the contents of an interior node with a leaf successor that is
  		 * pinned by "next" pointers that are accessible independently of lock.
  		 * So instead we swap the tree linkages.
  		 */
  		final void deleteTreeNode(TreeNode<V> p) {
  			TreeNode<V> next = (TreeNode<V>) p.next; // unlink traversal
  														// pointers
  			TreeNode<V> pred = p.prev;
  			if (pred == null)
  				first = next;
  			else
  				pred.next = next;
  			if (next != null)
  				next.prev = pred;
  			TreeNode<V> replacement;
  			TreeNode<V> pl = p.left;
  			TreeNode<V> pr = p.right;
  			if (pl != null && pr != null) {
  				TreeNode<V> s = pr, sl;
  				while ((sl = s.left) != null) // find successor
  					s = sl;
  				boolean c = s.red;
  				s.red = p.red;
  				p.red = c; // swap colors
  				TreeNode<V> sr = s.right;
  				TreeNode<V> pp = p.parent;
  				if (s == pr) { // p was s's direct parent
  					p.parent = s;
  					s.right = p;
  				} else {
  					TreeNode<V> sp = s.parent;
  					if ((p.parent = sp) != null) {
  						if (s == sp.left)
  							sp.left = p;
  						else
  							sp.right = p;
  					}
  					if ((s.right = pr) != null)
  						pr.parent = s;
  				}
  				p.left = null;
  				if ((p.right = sr) != null)
  					sr.parent = p;
  				if ((s.left = pl) != null)
  					pl.parent = s;
  				if ((s.parent = pp) == null)
  					root = s;
  				else if (p == pp.left)
  					pp.left = s;
  				else
  					pp.right = s;
  				replacement = sr;
  			} else
  				replacement = (pl != null) ? pl : pr;
  			TreeNode<V> pp = p.parent;
  			if (replacement == null) {
  				if (pp == null) {
  					root = null;
  					return;
  				}
  				replacement = p;
  			} else {
  				replacement.parent = pp;
  				if (pp == null)
  					root = replacement;
  				else if (p == pp.left)
  					pp.left = replacement;
  				else
  					pp.right = replacement;
  				p.left = p.right = p.parent = null;
  			}
  			if (!p.red) { // rebalance, from CLR
  				TreeNode<V> x = replacement;
  				while (x != null) {
  					TreeNode<V> xp, xpl;
  					if (x.red || (xp = x.parent) == null) {
  						x.red = false;
  						break;
  					}
  					if (x == (xpl = xp.left)) {
  						TreeNode<V> sib = xp.right;
  						if (sib != null && sib.red) {
  							sib.red = false;
  							xp.red = true;
  							rotateLeft(xp);
  							sib = (xp = x.parent) == null ? null : xp.right;
  						}
  						if (sib == null)
  							x = xp;
  						else {
  							TreeNode<V> sl = sib.left, sr = sib.right;
  							if ((sr == null || !sr.red) && (sl == null || !sl.red)) {
  								sib.red = true;
  								x = xp;
  							} else {
  								if (sr == null || !sr.red) {
  									if (sl != null)
  										sl.red = false;
  									sib.red = true;
  									rotateRight(sib);
  									sib = (xp = x.parent) == null ? null : xp.right;
  								}
  								if (sib != null) {
  									sib.red = (xp == null) ? false : xp.red;
  									if ((sr = sib.right) != null)
  										sr.red = false;
  								}
  								if (xp != null) {
  									xp.red = false;
  									rotateLeft(xp);
  								}
  								x = root;
  							}
  						}
  					} else { // symmetric
  						TreeNode<V> sib = xpl;
  						if (sib != null && sib.red) {
  							sib.red = false;
  							xp.red = true;
  							rotateRight(xp);
  							sib = (xp = x.parent) == null ? null : xp.left;
  						}
  						if (sib == null)
  							x = xp;
  						else {
  							TreeNode<V> sl = sib.left, sr = sib.right;
  							if ((sl == null || !sl.red) && (sr == null || !sr.red)) {
  								sib.red = true;
  								x = xp;
  							} else {
  								if (sl == null || !sl.red) {
  									if (sr != null)
  										sr.red = false;
  									sib.red = true;
  									rotateLeft(sib);
  									sib = (xp = x.parent) == null ? null : xp.left;
  								}
  								if (sib != null) {
  									sib.red = (xp == null) ? false : xp.red;
  									if ((sl = sib.left) != null)
  										sl.red = false;
  								}
  								if (xp != null) {
  									xp.red = false;
  									rotateRight(xp);
  								}
  								x = root;
  							}
  						}
  					}
  				}
  			}
  			if (p == replacement && (pp = p.parent) != null) {
  				if (p == pp.left) // detach pointers
  					pp.left = null;
  				else if (p == pp.right)
  					pp.right = null;
  				p.parent = null;
  			}
  		}
  	}
  
  	/* ---------------- Collision reduction methods -------------- */
  	/**
  	 * Spreads higher bits to lower, and also forces top bit to 0. Because the
  	 * table uses power-of-two masking, sets of hashes that vary only in bits
  	 * above the current mask will always collide. (Among known examples are
  	 * sets of Float keys holding consecutive whole numbers in small tables.) To
  	 * counter this, we apply a transform that spreads the impact of higher bits
  	 * downward. There is a tradeoff between speed, utility, and quality of
  	 * bit-spreading. Because many common sets of hashes are already reasonably
  	 * distributed across bits (so don't benefit from spreading), and because we
  	 * use trees to handle large sets of collisions in bins, we don't need
  	 * excessively high quality.
  	 */
  	private static final int spread(int h) {
  		h ^= (h >>> 18) ^ (h >>> 12);
  		return (h ^ (h >>> 10)) & HASH_BITS;
  	}
  
  	/**
  	 * Replaces a list bin with a tree bin if key is comparable. Call only when
  	 * locked.
  	 */
  	private final void replaceWithTreeBin(Node<V>[] tab, int index, Object key) {
  		if (key instanceof Comparable) {
  			TreeBin<V> t = new TreeBin<V>();
  			for (Node<V> e = tabAt(tab, index); e != null; e = e.next)
  				t.putTreeNode(e.hash, e.key, e.val);
  			setTabAt(tab, index, new Node<V>(MOVED, t, null, null));
  		}
  	}
  
  	/* ---------------- Internal access and update methods -------------- */
  	/**
  	 * Implementation for get and containsKey
  	 */
  	@SuppressWarnings("unchecked")
  	private final V internalGet(Object k) {
  		int h = spread(k.hashCode());
  		retry: for (Node<V>[] tab = table; tab != null;) {
  			Node<V> e;
  			Object ek;
  			V ev;
  			int eh; // locals to read fields once
  			for (e = tabAt(tab, (tab.length - 1) & h); e != null; e = e.next) {
  				if ((eh = e.hash) < 0) {
  					if ((ek = e.key) instanceof TreeBin) // search TreeBin
  						return ((TreeBin<V>) ek).getValue(h, k);
  					else { // restart with new table
  						tab = (Node<V>[]) ek;
  						continue retry;
  					}
  				} else if (eh == h && (ev = e.val) != null && ((ek = e.key) == k || k.equals(ek)))
  					return ev;
  			}
  			break;
  		}
  		return null;
  	}
  
  	/**
  	 * Implementation for the four public remove/replace methods: Replaces node
  	 * value with v, conditional upon match of cv if non-null. If resulting
  	 * value is null, delete.
  	 */
  	@SuppressWarnings("unchecked")
  	private final V internalReplace(Object k, V v, Object cv) {
  		int h = spread(k.hashCode());
  		V oldVal = null;
  		for (Node<V>[] tab = table;;) {
  			Node<V> f;
  			int i, fh;
  			Object fk;
  			if (tab == null || (f = tabAt(tab, i = (tab.length - 1) & h)) == null)
  				break;
  			else if ((fh = f.hash) < 0) {
  				if ((fk = f.key) instanceof TreeBin) {
  					TreeBin<V> t = (TreeBin<V>) fk;
  					boolean validated = false;
  					boolean deleted = false;
  					t.acquire(0);
  					try {
  						if (tabAt(tab, i) == f) {
  							validated = true;
  							TreeNode<V> p = t.getTreeNode(h, k, t.root);
  							if (p != null) {
  								V pv = p.val;
  								if (cv == null || cv == pv || cv.equals(pv)) {
  									oldVal = pv;
  									if ((p.val = v) == null) {
  										deleted = true;
  										t.deleteTreeNode(p);
  									}
  								}
  							}
  						}
  					} finally {
  						t.release(0);
  					}
  					if (validated) {
  						if (deleted)
  							addCount(-1L, -1);
  						break;
  					}
  				} else
  					tab = (Node<V>[]) fk;
  			} else if (fh != h && f.next == null) // precheck
  				break; // rules out possible existence
  			else {
  				boolean validated = false;
  				boolean deleted = false;
  				synchronized (f) {
  					if (tabAt(tab, i) == f) {
  						validated = true;
  						for (Node<V> e = f, pred = null;;) {
  							Object ek;
  							V ev;
  							if (e.hash == h && ((ev = e.val) != null) && ((ek = e.key) == k || k.equals(ek))) {
  								if (cv == null || cv == ev || cv.equals(ev)) {
  									oldVal = ev;
  									if ((e.val = v) == null) {
  										deleted = true;
  										Node<V> en = e.next;
  										if (pred != null)
  											pred.next = en;
  										else
  											setTabAt(tab, i, en);
  									}
  								}
  								break;
  							}
  							pred = e;
  							if ((e = e.next) == null)
  								break;
  						}
  					}
  				}
  				if (validated) {
  					if (deleted)
  						addCount(-1L, -1);
  					break;
  				}
  			}
  		}
  		return oldVal;
  	}
  
  	/*
  	 * Internal versions of insertion methods All have the same basic structure
  	 * as the first (internalPut): 1. If table uninitialized, create 2. If bin
  	 * empty, try to CAS new node 3. If bin stale, use new table 4. if bin
  	 * converted to TreeBin, validate and relay to TreeBin methods 5. Lock and
  	 * validate; if valid, scan and add or update
  	 *
  	 * The putAll method differs mainly in attempting to pre-allocate enough
  	 * table space, and also more lazily performs count updates and checks.
  	 *
  	 * Most of the function-accepting methods can't be factored nicely because
  	 * they require different functional forms, so instead sprawl out similar
  	 * mechanics.
  	 */
  	/**
  	 * Implementation for put and putIfAbsent
  	 */
  	@SuppressWarnings("unchecked")
  	private final V internalPut(K k, V v, boolean onlyIfAbsent) {
  		if (k == null || v == null)
  			throw new NullPointerException();
  		int h = spread(k.hashCode());
  		int len = 0;
  		for (Node<V>[] tab = table;;) {
  			int i, fh;
  			Node<V> f;
  			Object fk;
  			V fv;
  			if (tab == null)
  				tab = initTable();
  			else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
  				if (casTabAt(tab, i, null, new Node<V>(h, k, v, null)))
  					break; // no lock when adding to empty bin
  			} else if ((fh = f.hash) < 0) {
  				if ((fk = f.key) instanceof TreeBin) {
  					TreeBin<V> t = (TreeBin<V>) fk;
  					V oldVal = null;
  					t.acquire(0);
  					try {
  						if (tabAt(tab, i) == f) {
  							len = 2;
  							TreeNode<V> p = t.putTreeNode(h, k, v);
  							if (p != null) {
  								oldVal = p.val;
  								if (!onlyIfAbsent)
  									p.val = v;
  							}
  						}
  					} finally {
  						t.release(0);
  					}
  					if (len != 0) {
  						if (oldVal != null)
  							return oldVal;
  						break;
  					}
  				} else
  					tab = (Node<V>[]) fk;
  			} else if (onlyIfAbsent && fh == h && (fv = f.val) != null && ((fk = f.key) == k || k.equals(fk))) // peek
  																												// while
  																												// nearby
  				return fv;
  			else {
  				V oldVal = null;
  				synchronized (f) {
  					if (tabAt(tab, i) == f) {
  						len = 1;
  						for (Node<V> e = f;; ++len) {
  							Object ek;
  							V ev;
  							if (e.hash == h && (ev = e.val) != null && ((ek = e.key) == k || k.equals(ek))) {
  								oldVal = ev;
  								if (!onlyIfAbsent)
  									e.val = v;
  								break;
  							}
  							Node<V> last = e;
  							if ((e = e.next) == null) {
  								last.next = new Node<V>(h, k, v, null);
  								if (len >= TREE_THRESHOLD)
  									replaceWithTreeBin(tab, i, k);
  								break;
  							}
  						}
  					}
  				}
  				if (len != 0) {
  					if (oldVal != null)
  						return oldVal;
  					break;
  				}
  			}
  		}
  		addCount(1L, len);
  		return null;
  	}
  
  	/**
  	 * Implementation for computeIfAbsent
  	 */
  	@SuppressWarnings("unchecked")
  	private final V internalComputeIfAbsent(K k, Fun<? super K, ? extends V> mf) {
  		if (k == null || mf == null)
  			throw new NullPointerException();
  		int h = spread(k.hashCode());
  		V val = null;
  		int len = 0;
  		for (Node<V>[] tab = table;;) {
  			Node<V> f;
  			int i;
  			Object fk;
  			if (tab == null)
  				tab = initTable();
  			else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
  				Node<V> node = new Node<V>(h, k, null, null);
  				synchronized (node) {
  					if (casTabAt(tab, i, null, node)) {
  						len = 1;
  						try {
  							if ((val = mf.apply(k)) != null)
  								node.val = val;
  						} finally {
  							if (val == null)
  								setTabAt(tab, i, null);
  						}
  					}
  				}
  				if (len != 0)
  					break;
  			} else if (f.hash < 0) {
  				if ((fk = f.key) instanceof TreeBin) {
  					TreeBin<V> t = (TreeBin<V>) fk;
  					boolean added = false;
  					t.acquire(0);
  					try {
  						if (tabAt(tab, i) == f) {
  							len = 1;
  							TreeNode<V> p = t.getTreeNode(h, k, t.root);
  							if (p != null)
  								val = p.val;
  							else if ((val = mf.apply(k)) != null) {
  								added = true;
  								len = 2;
  								t.putTreeNode(h, k, val);
  							}
  						}
  					} finally {
  						t.release(0);
  					}
  					if (len != 0) {
  						if (!added)
  							return val;
  						break;
  					}
  				} else
  					tab = (Node<V>[]) fk;
  			} else {
  				for (Node<V> e = f; e != null; e = e.next) { // prescan
  					Object ek;
  					V ev;
  					if (e.hash == h && (ev = e.val) != null && ((ek = e.key) == k || k.equals(ek)))
  						return ev;
  				}
  				boolean added = false;
  				synchronized (f) {
  					if (tabAt(tab, i) == f) {
  						len = 1;
  						for (Node<V> e = f;; ++len) {
  							Object ek;
  							V ev;
  							if (e.hash == h && (ev = e.val) != null && ((ek = e.key) == k || k.equals(ek))) {
  								val = ev;
  								break;
  							}
  							Node<V> last = e;
  							if ((e = e.next) == null) {
  								if ((val = mf.apply(k)) != null) {
  									added = true;
  									last.next = new Node<V>(h, k, val, null);
  									if (len >= TREE_THRESHOLD)
  										replaceWithTreeBin(tab, i, k);
  								}
  								break;
  							}
  						}
  					}
  				}
  				if (len != 0) {
  					if (!added)
  						return val;
  					break;
  				}
  			}
  		}
  		if (val != null)
  			addCount(1L, len);
  		return val;
  	}
  
  	/**
  	 * Implementation for compute
  	 */
  	@SuppressWarnings("unchecked")
  	private final V internalCompute(K k, boolean onlyIfPresent, BiFun<? super K, ? super V, ? extends V> mf) {
  		if (k == null || mf == null)
  			throw new NullPointerException();
  		int h = spread(k.hashCode());
  		V val = null;
  		int delta = 0;
  		int len = 0;
  		for (Node<V>[] tab = table;;) {
  			Node<V> f;
  			int i;
  			Object fk;
  			if (tab == null)
  				tab = initTable();
  			else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
  				if (onlyIfPresent)
  					break;
  				Node<V> node = new Node<V>(h, k, null, null);
  				synchronized (node) {
  					if (casTabAt(tab, i, null, node)) {
  						try {
  							len = 1;
  							if ((val = mf.apply(k, null)) != null) {
  								node.val = val;
  								delta = 1;
  							}
  						} finally {
  							if (delta == 0)
  								setTabAt(tab, i, null);
  						}
  					}
  				}
  				if (len != 0)
  					break;
  			} else if ((f.hash) < 0) {
  				if ((fk = f.key) instanceof TreeBin) {
  					TreeBin<V> t = (TreeBin<V>) fk;
  					t.acquire(0);
  					try {
  						if (tabAt(tab, i) == f) {
  							len = 1;
  							TreeNode<V> p = t.getTreeNode(h, k, t.root);
  							if (p == null && onlyIfPresent)
  								break;
  							V pv = (p == null) ? null : p.val;
  							if ((val = mf.apply(k, pv)) != null) {
  								if (p != null)
  									p.val = val;
  								else {
  									len = 2;
  									delta = 1;
  									t.putTreeNode(h, k, val);
  								}
  							} else if (p != null) {
  								delta = -1;
  								t.deleteTreeNode(p);
  							}
  						}
  					} finally {
  						t.release(0);
  					}
  					if (len != 0)
  						break;
  				} else
  					tab = (Node<V>[]) fk;
  			} else {
  				synchronized (f) {
  					if (tabAt(tab, i) == f) {
  						len = 1;
  						for (Node<V> e = f, pred = null;; ++len) {
  							Object ek;
  							V ev;
  							if (e.hash == h && (ev = e.val) != null && ((ek = e.key) == k || k.equals(ek))) {
  								val = mf.apply(k, ev);
  								if (val != null)
  									e.val = val;
  								else {
  									delta = -1;
  									Node<V> en = e.next;
  									if (pred != null)
  										pred.next = en;
  									else
  										setTabAt(tab, i, en);
  								}
  								break;
  							}
  							pred = e;
  							if ((e = e.next) == null) {
  								if (!onlyIfPresent && (val = mf.apply(k, null)) != null) {
  									pred.next = new Node<V>(h, k, val, null);
  									delta = 1;
  									if (len >= TREE_THRESHOLD)
  										replaceWithTreeBin(tab, i, k);
  								}
  								break;
  							}
  						}
  					}
  				}
  				if (len != 0)
  					break;
  			}
  		}
  		if (delta != 0)
  			addCount(delta, len);
  		return val;
  	}
  
  	/**
  	 * Implementation for merge
  	 */
  	@SuppressWarnings("unchecked")
  	private final V internalMerge(K k, V v, BiFun<? super V, ? super V, ? extends V> mf) {
  		if (k == null || v == null || mf == null)
  			throw new NullPointerException();
  		int h = spread(k.hashCode());
  		V val = null;
  		int delta = 0;
  		int len = 0;
  		for (Node<V>[] tab = table;;) {
  			int i;
  			Node<V> f;
  			Object fk;
  			if (tab == null)
  				tab = initTable();
  			else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
  				if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
  					delta = 1;
  					val = v;
  					break;
  				}
  			} else if (f.hash < 0) {
  				if ((fk = f.key) instanceof TreeBin) {
  					TreeBin<V> t = (TreeBin<V>) fk;
  					t.acquire(0);
  					try {
  						if (tabAt(tab, i) == f) {
  							len = 1;
  							TreeNode<V> p = t.getTreeNode(h, k, t.root);
  							val = (p == null) ? v : mf.apply(p.val, v);
  							if (val != null) {
  								if (p != null)
  									p.val = val;
  								else {
  									len = 2;
  									delta = 1;
  									t.putTreeNode(h, k, val);
  								}
  							} else if (p != null) {
  								delta = -1;
  								t.deleteTreeNode(p);
  							}
  						}
  					} finally {
  						t.release(0);
  					}
  					if (len != 0)
  						break;
  				} else
  					tab = (Node<V>[]) fk;
  			} else {
  				synchronized (f) {
  					if (tabAt(tab, i) == f) {
  						len = 1;
  						for (Node<V> e = f, pred = null;; ++len) {
  							Object ek;
  							V ev;
  							if (e.hash == h && (ev = e.val) != null && ((ek = e.key) == k || k.equals(ek))) {
  								val = mf.apply(ev, v);
  								if (val != null)
  									e.val = val;
  								else {
  									delta = -1;
  									Node<V> en = e.next;
  									if (pred != null)
  										pred.next = en;
  									else
  										setTabAt(tab, i, en);
  								}
  								break;
  							}
  							pred = e;
  							if ((e = e.next) == null) {
  								val = v;
  								pred.next = new Node<V>(h, k, val, null);
  								delta = 1;
  								if (len >= TREE_THRESHOLD)
  									replaceWithTreeBin(tab, i, k);
  								break;
  							}
  						}
  					}
  				}
  				if (len != 0)
  					break;
  			}
  		}
  		if (delta != 0)
  			addCount(delta, len);
  		return val;
  	}
  
  	/**
  	 * Implementation for putAll
  	 */
  	@SuppressWarnings("unchecked")
  	private final void internalPutAll(Map<? extends K, ? extends V> m) {
  		tryPresize(m.size());
  		long delta = 0L; // number of uncommitted additions
  		boolean npe = false; // to throw exception on exit for nulls
  		try { // to clean up counts on other exceptions
  			for (Map.Entry<?, ? extends V> entry : m.entrySet()) {
  				Object k;
  				V v;
  				if (entry == null || (k = entry.getKey()) == null || (v = entry.getValue()) == null) {
  					npe = true;
  					break;
  				}
  				int h = spread(k.hashCode());
  				for (Node<V>[] tab = table;;) {
  					int i;
  					Node<V> f;
  					Object fk;
  					if (tab == null)
  						tab = initTable();
  					else if ((f = tabAt(tab, i = (tab.length - 1) & h)) == null) {
  						if (casTabAt(tab, i, null, new Node<V>(h, k, v, null))) {
  							++delta;
  							break;
  						}
  					} else if ((f.hash) < 0) {
  						if ((fk = f.key) instanceof TreeBin) {
  							TreeBin<V> t = (TreeBin<V>) fk;
  							boolean validated = false;
  							t.acquire(0);
  							try {
  								if (tabAt(tab, i) == f) {
  									validated = true;
  									TreeNode<V> p = t.getTreeNode(h, k, t.root);
  									if (p != null)
  										p.val = v;
  									else {
  										t.putTreeNode(h, k, v);
  										++delta;
  									}
  								}
  							} finally {
  								t.release(0);
  							}
  							if (validated)
  								break;
  						} else
  							tab = (Node<V>[]) fk;
  					} else {
  						int len = 0;
  						synchronized (f) {
  							if (tabAt(tab, i) == f) {
  								len = 1;
  								for (Node<V> e = f;; ++len) {
  									Object ek;
  									if (e.hash == h && (e.val) != null && ((ek = e.key) == k || k.equals(ek))) {
  										e.val = v;
  										break;
  									}
  									Node<V> last = e;
  									if ((e = e.next) == null) {
  										++delta;
  										last.next = new Node<V>(h, k, v, null);
  										if (len >= TREE_THRESHOLD)
  											replaceWithTreeBin(tab, i, k);
  										break;
  									}
  								}
  							}
  						}
  						if (len != 0) {
  							if (len > 1) {
  								addCount(delta, len);
  								delta = 0L;
  							}
  							break;
  						}
  					}
  				}
  			}
  		} finally {
  			if (delta != 0L)
  				addCount(delta, 2);
  		}
  		if (npe)
  			throw new NullPointerException();
  	}
  
  	/**
  	 * Implementation for clear. Steps through each bin, removing all nodes.
  	 */
  	@SuppressWarnings("unchecked")
  	private final void internalClear() {
  		long delta = 0L; // negative number of deletions
  		int i = 0;
  		Node<V>[] tab = table;
  		while (tab != null && i < tab.length) {
  			Node<V> f = tabAt(tab, i);
  			if (f == null)
  				++i;
  			else if (f.hash < 0) {
  				Object fk;
  				if ((fk = f.key) instanceof TreeBin) {
  					TreeBin<V> t = (TreeBin<V>) fk;
  					t.acquire(0);
  					try {
  						if (tabAt(tab, i) == f) {
  							for (Node<V> p = t.first; p != null; p = p.next) {
  								if (p.val != null) { // (currently always true)
  									p.val = null;
  									--delta;
  								}
  							}
  							t.first = null;
  							t.root = null;
  							++i;
  						}
  					} finally {
  						t.release(0);
  					}
  				} else
  					tab = (Node<V>[]) fk;
  			} else {
  				synchronized (f) {
  					if (tabAt(tab, i) == f) {
  						for (Node<V> e = f; e != null; e = e.next) {
  							if (e.val != null) { // (currently always true)
  								e.val = null;
  								--delta;
  							}
  						}
  						setTabAt(tab, i, null);
  						++i;
  					}
  				}
  			}
  		}
  		if (delta != 0L)
  			addCount(delta, -1);
  	}
  
  	/* ---------------- Table Initialization and Resizing -------------- */
  	/**
  	 * Returns a power of two table size for the given desired capacity. See
  	 * Hackers Delight, sec 3.2
  	 */
  	private static final int tableSizeFor(int c) {
  		int n = c - 1;
  		n |= n >>> 1;
  		n |= n >>> 2;
  		n |= n >>> 4;
  		n |= n >>> 8;
  		n |= n >>> 16;
  		return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1;
  	}
  
  	/**
  	 * Initializes table, using the size recorded in sizeCtl.
  	 */
  	@SuppressWarnings("unchecked")
  	private final Node<V>[] initTable() {
  		Node<V>[] tab;
  		int sc;
  		while ((tab = table) == null) {
  			if ((sc = sizeCtl) < 0)
  				Thread.yield(); // lost initialization race; just spin
  			else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
  				try {
  					if ((tab = table) == null) {
  						int n = (sc > 0) ? sc : DEFAULT_CAPACITY;
  						@SuppressWarnings("rawtypes")
  						Node[] tb = new Node[n];
  						table = tab = tb;
  						sc = n - (n >>> 2);
  					}
  				} finally {
  					sizeCtl = sc;
  				}
  				break;
  			}
  		}
  		return tab;
  	}
  
  	/**
  	 * Adds to count, and if table is too small and not already resizing,
  	 * initiates transfer. If already resizing, helps perform transfer if work
  	 * is available. Rechecks occupancy after a transfer to see if another
  	 * resize is already needed because resizings are lagging additions.
  	 *
  	 * @param x
  	 *            the count to add
  	 * @param check
  	 *            if <0, don't check resize, if <= 1 only check if uncontended
  	 */
  	private final void addCount(long x, int check) {
  		CounterCell[] as;
  		long b, s;
  		if ((as = counterCells) != null || !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) {
  			CounterHashCode hc;
  			CounterCell a;
  			long v;
  			int m;
  			boolean uncontended = true;
  			if ((hc = threadCounterHashCode.get()) == null || as == null || (m = as.length - 1) < 0
  					|| (a = as[m & hc.code]) == null
  					|| !(uncontended = U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) {
  				fullAddCount(x, hc, uncontended);
  				return;
  			}
  			if (check <= 1)
  				return;
  			s = sumCount();
  		}
  		if (check >= 0) {
  			Node<V>[] tab, nt;
  			int sc;
  			while (s >= (sc = sizeCtl) && (tab = table) != null && tab.length < MAXIMUM_CAPACITY) {
  				if (sc < 0) {
  					if (sc == -1 || transferIndex <= transferOrigin || (nt = nextTable) == null)
  						break;
  					if (U.compareAndSwapInt(this, SIZECTL, sc, sc - 1))
  						transfer(tab, nt);
  				} else if (U.compareAndSwapInt(this, SIZECTL, sc, -2))
  					transfer(tab, null);
  				s = sumCount();
  			}
  		}
  	}
  
  	/**
  	 * Tries to presize table to accommodate the given number of elements.
  	 *
  	 * @param size
  	 *            number of elements (doesn't need to be perfectly accurate)
  	 */
  	@SuppressWarnings("unchecked")
  	private final void tryPresize(int size) {
  		int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : tableSizeFor(size + (size >>> 1) + 1);
  		int sc;
  		while ((sc = sizeCtl) >= 0) {
  			Node<V>[] tab = table;
  			int n;
  			if (tab == null || (n = tab.length) == 0) {
  				n = (sc > c) ? sc : c;
  				if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
  					try {
  						if (table == tab) {
  							@SuppressWarnings("rawtypes")
  							Node[] tb = new Node[n];
  							table = tb;
  							sc = n - (n >>> 2);
  						}
  					} finally {
  						sizeCtl = sc;
  					}
  				}
  			} else if (c <= sc || n >= MAXIMUM_CAPACITY)
  				break;
  			else if (tab == table && U.compareAndSwapInt(this, SIZECTL, sc, -2))
  				transfer(tab, null);
  		}
  	}
  
  	/**
  	 * Moves and/or copies the nodes in each bin to new table. See above for
  	 * explanation.
  	 */
  	@SuppressWarnings("unchecked")
  	private final void transfer(Node<V>[] tab, Node<V>[] nextTab) {
  		int n = tab.length, stride;
  		if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE)
  			stride = MIN_TRANSFER_STRIDE; // subdivide range
  		if (nextTab == null) { // initiating
  			try {
  				@SuppressWarnings("rawtypes")
  				Node[] tb = new Node[n << 1];
  				nextTab = tb;
  			} catch (Throwable ex) { // try to cope with OOME
  				sizeCtl = Integer.MAX_VALUE;
  				return;
  			}
  			nextTable = nextTab;
  			transferOrigin = n;
  			transferIndex = n;
  			Node<V> rev = new Node<V>(MOVED, tab, null, null);
  			for (int k = n; k > 0;) { // progressively reveal ready slots
  				int nextk = (k > stride) ? k - stride : 0;
  				for (int m = nextk; m < k; ++m)
  					nextTab[m] = rev;
  				for (int m = n + nextk; m < n + k; ++m)
  					nextTab[m] = rev;
  				U.putOrderedInt(this, TRANSFERORIGIN, k = nextk);
  			}
  		}
  		int nextn = nextTab.length;
  		Node<V> fwd = new Node<V>(MOVED, nextTab, null, null);
  		boolean advance = true;
  		for (int i = 0, bound = 0;;) {
  			int nextIndex, nextBound;
  			Node<V> f;
  			Object fk;
  			while (advance) {
  				if (--i >= bound)
  					advance = false;
  				else if ((nextIndex = transferIndex) <= transferOrigin) {
  					i = -1;
  					advance = false;
  				} else if (U.compareAndSwapInt(this, TRANSFERINDEX, nextIndex,
  						nextBound = (nextIndex > stride ? nextIndex - stride : 0))) {
  					bound = nextBound;
  					i = nextIndex - 1;
  					advance = false;
  				}
  			}
  			if (i < 0 || i >= n || i + n >= nextn) {
  				for (int sc;;) {
  					if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, ++sc)) {
  						if (sc == -1) {
  							nextTable = null;
  							table = nextTab;
  							sizeCtl = (n << 1) - (n >>> 1);
  						}
  						return;
  					}
  				}
  			} else if ((f = tabAt(tab, i)) == null) {
  				if (casTabAt(tab, i, null, fwd)) {
  					setTabAt(nextTab, i, null);
  					setTabAt(nextTab, i + n, null);
  					advance = true;
  				}
  			} else if (f.hash >= 0) {
  				synchronized (f) {
  					if (tabAt(tab, i) == f) {
  						int runBit = f.hash & n;
  						Node<V> lastRun = f, lo = null, hi = null;
  						for (Node<V> p = f.next; p != null; p = p.next) {
  							int b = p.hash & n;
  							if (b != runBit) {
  								runBit = b;
  								lastRun = p;
  							}
  						}
  						if (runBit == 0)
  							lo = lastRun;
  						else
  							hi = lastRun;
  						for (Node<V> p = f; p != lastRun; p = p.next) {
  							int ph = p.hash;
  							Object pk = p.key;
  							V pv = p.val;
  							if ((ph & n) == 0)
  								lo = new Node<V>(ph, pk, pv, lo);
  							else
  								hi = new Node<V>(ph, pk, pv, hi);
  						}
  						setTabAt(nextTab, i, lo);
  						setTabAt(nextTab, i + n, hi);
  						setTabAt(tab, i, fwd);
  						advance = true;
  					}
  				}
  			} else if ((fk = f.key) instanceof TreeBin) {
  				TreeBin<V> t = (TreeBin<V>) fk;
  				t.acquire(0);
  				try {
  					if (tabAt(tab, i) == f) {
  						TreeBin<V> lt = new TreeBin<V>();
  						TreeBin<V> ht = new TreeBin<V>();
  						int lc = 0, hc = 0;
  						for (Node<V> e = t.first; e != null; e = e.next) {
  							int h = e.hash;
  							Object k = e.key;
  							V v = e.val;
  							if ((h & n) == 0) {
  								++lc;
  								lt.putTreeNode(h, k, v);
  							} else {
  								++hc;
  								ht.putTreeNode(h, k, v);
  							}
  						}
  						Node<V> ln, hn; // throw away trees if too small
  						if (lc < TREE_THRESHOLD) {
  							ln = null;
  							for (Node<V> p = lt.first; p != null; p = p.next)
  								ln = new Node<V>(p.hash, p.key, p.val, ln);
  						} else
  							ln = new Node<V>(MOVED, lt, null, null);
  						setTabAt(nextTab, i, ln);
  						if (hc < TREE_THRESHOLD) {
  							hn = null;
  							for (Node<V> p = ht.first; p != null; p = p.next)
  								hn = new Node<V>(p.hash, p.key, p.val, hn);
  						} else
  							hn = new Node<V>(MOVED, ht, null, null);
  						setTabAt(nextTab, i + n, hn);
  						setTabAt(tab, i, fwd);
  						advance = true;
  					}
  				} finally {
  					t.release(0);
  				}
  			} else
  				advance = true; // already processed
  		}
  	}
  
  	/* ---------------- Counter support -------------- */
  	final long sumCount() {
  		CounterCell[] as = counterCells;
  		CounterCell a;
  		long sum = baseCount;
  		if (as != null) {
  			for (int i = 0; i < as.length; ++i) {
  				if ((a = as[i]) != null)
  					sum += a.value;
  			}
  		}
  		return sum;
  	}
  
  	// See LongAdder version for explanation
  	private final void fullAddCount(long x, CounterHashCode hc, boolean wasUncontended) {
  		int h;
  		if (hc == null) {
  			hc = new CounterHashCode();
  			int s = counterHashCodeGenerator.addAndGet(SEED_INCREMENT);
  			h = hc.code = (s == 0) ? 1 : s; // Avoid zero
  			threadCounterHashCode.set(hc);
  		} else
  			h = hc.code;
  		boolean collide = false; // True if last slot nonempty
  		for (;;) {
  			CounterCell[] as;
  			CounterCell a;
  			int n;
  			long v;
  			if ((as = counterCells) != null && (n = as.length) > 0) {
  				if ((a = as[(n - 1) & h]) == null) {
  					if (counterBusy == 0) { // Try to attach new Cell
  						CounterCell r = new CounterCell(x); // Optimistic create
  						if (counterBusy == 0 && U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
  							boolean created = false;
  							try { // Recheck under lock
  								CounterCell[] rs;
  								int m, j;
  								if ((rs = counterCells) != null && (m = rs.length) > 0 && rs[j = (m - 1) & h] == null) {
  									rs[j] = r;
  									created = true;
  								}
  							} finally {
  								counterBusy = 0;
  							}
  							if (created)
  								break;
  							continue; // Slot is now non-empty
  						}
  					}
  					collide = false;
  				} else if (!wasUncontended) // CAS already known to fail
  					wasUncontended = true; // Continue after rehash
  				else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))
  					break;
  				else if (counterCells != as || n >= NCPU)
  					collide = false; // At max size or stale
  				else if (!collide)
  					collide = true;
  				else if (counterBusy == 0 && U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
  					try {
  						if (counterCells == as) {// Expand table unless stale
  							CounterCell[] rs = new CounterCell[n << 1];
  							for (int i = 0; i < n; ++i)
  								rs[i] = as[i];
  							counterCells = rs;
  						}
  					} finally {
  						counterBusy = 0;
  					}
  					collide = false;
  					continue; // Retry with expanded table
  				}
  				h ^= h << 13; // Rehash
  				h ^= h >>> 17;
  				h ^= h << 5;
  			} else if (counterBusy == 0 && counterCells == as && U.compareAndSwapInt(this, COUNTERBUSY, 0, 1)) {
  				boolean init = false;
  				try { // Initialize table
  					if (counterCells == as) {
  						CounterCell[] rs = new CounterCell[2];
  						rs[h & 1] = new CounterCell(x);
  						counterCells = rs;
  						init = true;
  					}
  				} finally {
  					counterBusy = 0;
  				}
  				if (init)
  					break;
  			} else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x))
  				break; // Fall back on using base
  		}
  		hc.code = h; // Record index for next time
  	}
  
  	/* ----------------Table Traversal -------------- */
  	/**
  	 * Encapsulates traversal for methods such as containsValue; also serves as
  	 * a base class for other iterators and bulk tasks.
  	 *
  	 * At each step, the iterator snapshots the key ("nextKey") and value
  	 * ("nextVal") of a valid node (i.e., one that, at point of snapshot, has a
  	 * non-null user value). Because val fields can change (including to null,
  	 * indicating deletion), field nextVal might not be accurate at point of
  	 * use, but still maintains the weak consistency property of holding a value
  	 * that was once valid. To support iterator.remove, the nextKey field is not
  	 * updated (nulled out) when the iterator cannot advance.
  	 *
  	 * Internal traversals directly access these fields, as in: {@code while
  	 * (it.advance() != null) { process(it.nextKey); }}
  	 *
  	 * Exported iterators must track whether the iterator has advanced (in
  	 * hasNext vs next) (by setting/checking/nulling field nextVal), and then
  	 * extract key, value, or key-value pairs as return values of next().
  	 *
  	 * The iterator visits once each still-valid node that was reachable upon
  	 * iterator construction. It might miss some that were added to a bin after
  	 * the bin was visited, which is OK wrt consistency guarantees. Maintaining
  	 * this property in the face of possible ongoing resizes requires a fair
  	 * amount of bookkeeping state that is difficult to optimize away amidst
  	 * volatile accesses. Even so, traversal maintains reasonable throughput.
  	 *
  	 * Normally, iteration proceeds bin-by-bin traversing lists. However, if the
  	 * table has been resized, then all future steps must traverse both the bin
  	 * at the current index as well as at (index + baseSize); and so on for
  	 * further resizings. To paranoically cope with potential sharing by users
  	 * of iterators across threads, iteration terminates if a bounds checks
  	 * fails for a table read.
  	 *
  	 * This class extends CountedCompleter to streamline parallel iteration in
  	 * bulk operations. This adds only a few fields of space overhead, which is
  	 * small enough in cases where it is not needed to not worry about it.
  	 * Because CountedCompleter is Serializable, but iterators need not be, we
  	 * need to add warning suppressions.
  	 */
  	@SuppressWarnings("serial")
  	static class Traverser<K, V, R> extends CountedCompleter<R> {
  
  		final ConcurrentHashMapV8<K, V> map;
  		Node<V> next; // the next entry to use
  		Object nextKey; // cached key field of next
  		V nextVal; // cached val field of next
  		Node<V>[] tab; // current table; updated if resized
  		int index; // index of bin to use next
  		int baseIndex; // current index of initial table
  		int baseLimit; // index bound for initial table
  		int baseSize; // initial table size
  		int batch; // split control
  
  		/**
  		 * Creates iterator for all entries in the table.
  		 */
  		Traverser(ConcurrentHashMapV8<K, V> map) {
  			this.map = map;
  		}
  
  		/**
  		 * Creates iterator for split() methods and task constructors
  		 */
  		Traverser(ConcurrentHashMapV8<K, V> map, Traverser<K, V, ?> it, int batch) {
  			super(it);
  			this.batch = batch;
  			if ((this.map = map) != null && it != null) { // split parent
  				Node<V>[] t;
  				if ((t = it.tab) == null && (t = it.tab = map.table) != null)
  					it.baseLimit = it.baseSize = t.length;
  				this.tab = t;
  				this.baseSize = it.baseSize;
  				int hi = this.baseLimit = it.baseLimit;
  				it.baseLimit = this.index = this.baseIndex = (hi + it.baseIndex + 1) >>> 1;
  			}
  		}
  
  		/**
  		 * Advances next; returns nextVal or null if terminated. See above for
  		 * explanation.
  		 */
  		@SuppressWarnings("unchecked")
  		final V advance() {
  			Node<V> e = next;
  			V ev = null;
  			outer: do {
  				if (e != null) // advance past used/skipped node
  					e = e.next;
  				while (e == null) { // get to next non-null bin
  					ConcurrentHashMapV8<K, V> m;
  					Node<V>[] t;
  					int b, i, n;
  					Object ek; // must use locals
  					if ((t = tab) != null)
  						n = t.length;
  					else if ((m = map) != null && (t = tab = m.table) != null)
  						n = baseLimit = baseSize = t.length;
  					else
  						break outer;
  					if ((b = baseIndex) >= baseLimit || (i = index) < 0 || i >= n)
  						break outer;
  					if ((e = tabAt(t, i)) != null && e.hash < 0) {
  						if ((ek = e.key) instanceof TreeBin)
  							e = ((TreeBin<V>) ek).first;
  						else {
  							tab = (Node<V>[]) ek;
  							continue; // restarts due to null val
  						}
  					} // visit upper slots if present
  					index = (i += baseSize) < n ? i : (baseIndex = b + 1);
  				}
  				nextKey = e.key;
  			} while ((ev = e.val) == null); // skip deleted or special nodes
  			next = e;
  			return nextVal = ev;
  		}
  
  		public final void remove() {
  			Object k = nextKey;
  			if (k == null && (advance() == null || (k = nextKey) == null))
  				throw new IllegalStateException();
  			map.internalReplace(k, null, null);
  		}
  
  		public final boolean hasNext() {
  			return nextVal != null || advance() != null;
  		}
  
  		public final boolean hasMoreElements() {
  			return hasNext();
  		}
  
  		@Override
  		public void compute() {
  		} // default no-op CountedCompleter body
  
  		/**
  		 * Returns a batch value > 0 if this task should (and must) be split, if
  		 * so, adding to pending count, and in any case updating batch value.
  		 * The initial batch value is approx exp2 of the number of times (minus
  		 * one) to split task by two before executing leaf action. This value is
  		 * faster to compute and more convenient to use as a guide to splitting
  		 * than is the depth, since it is used while dividing by two anyway.
  		 */
  		final int preSplit() {
  			ConcurrentHashMapV8<K, V> m;
  			int b;
  			Node<V>[] t;
  			ForkJoinPool pool;
  			if ((b = batch) < 0 && (m = map) != null) { // force initialization
  				if ((t = tab) == null && (t = tab = m.table) != null)
  					baseLimit = baseSize = t.length;
  				if (t != null) {
  					long n = m.sumCount();
  					int par = ((pool = getPool()) == null) ? ForkJoinPool.getCommonPoolParallelism()
  							: pool.getParallelism();
  					int sp = par << 3; // slack of 8
  					b = (n <= 0L) ? 0 : (n < sp) ? (int) n : sp;
  				}
  			}
  			b = (b <= 1 || baseIndex == baseLimit) ? 0 : (b >>> 1);
  			if ((batch = b) > 0)
  				addToPendingCount(1);
  			return b;
  		}
  	}
  
  	/* ---------------- Public operations -------------- */
  	/**
  	 * Creates a new, empty map with the default initial table size (16).
  	 */
  	public ConcurrentHashMapV8() {
  	}
  
  	/**
  	 * Creates a new, empty map with an initial table size accommodating the
  	 * specified number of elements without the need to dynamically resize.
  	 *
  	 * @param initialCapacity
  	 *            The implementation performs internal sizing to accommodate
  	 *            this many elements.
  	 * @throws IllegalArgumentException
  	 *             if the initial capacity of elements is negative
  	 */
  	public ConcurrentHashMapV8(int initialCapacity) {
  		if (initialCapacity < 0)
  			throw new IllegalArgumentException();
  		int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY
  				: tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1));
  		this.sizeCtl = cap;
  	}
  
  	/**
  	 * Creates a new map with the same mappings as the given map.
  	 *
  	 * @param m
  	 *            the map
  	 */
  	public ConcurrentHashMapV8(Map<? extends K, ? extends V> m) {
  		this.sizeCtl = DEFAULT_CAPACITY;
  		internalPutAll(m);
  	}
  
  	/**
  	 * Creates a new, empty map with an initial table size based on the given
  	 * number of elements ({@code initialCapacity}) and initial table density
  	 * ({@code loadFactor}).
  	 *
  	 * @param initialCapacity
  	 *            the initial capacity. The implementation performs internal
  	 *            sizing to accommodate this many elements, given the specified
  	 *            load factor.
  	 * @param loadFactor
  	 *            the load factor (table density) for establishing the initial
  	 *            table size
  	 * @throws IllegalArgumentException
  	 *             if the initial capacity of elements is negative or the load
  	 *             factor is nonpositive
  	 *
  	 * @since 1.6
  	 */
  	public ConcurrentHashMapV8(int initialCapacity, float loadFactor) {
  		this(initialCapacity, loadFactor, 1);
  	}
  
  	/**
  	 * Creates a new, empty map with an initial table size based on the given
  	 * number of elements ({@code initialCapacity}), table density
  	 * ({@code loadFactor}), and number of concurrently updating threads
  	 * ({@code concurrencyLevel}).
  	 *
  	 * @param initialCapacity
  	 *            the initial capacity. The implementation performs internal
  	 *            sizing to accommodate this many elements, given the specified
  	 *            load factor.
  	 * @param loadFactor
  	 *            the load factor (table density) for establishing the initial
  	 *            table size
  	 * @param concurrencyLevel
  	 *            the estimated number of concurrently updating threads. The
  	 *            implementation may use this value as a sizing hint.
  	 * @throws IllegalArgumentException
  	 *             if the initial capacity is negative or the load factor or
  	 *             concurrencyLevel are nonpositive
  	 */
  	public ConcurrentHashMapV8(int initialCapacity, float loadFactor, int concurrencyLevel) {
  		if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0)
  			throw new IllegalArgumentException();
  		if (initialCapacity < concurrencyLevel) // Use at least as many bins
  			initialCapacity = concurrencyLevel; // as estimated threads
  		long size = (long) (1.0 + initialCapacity / loadFactor);
  		int cap = (size >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : tableSizeFor((int) size);
  		this.sizeCtl = cap;
  	}
  
  	/**
  	 * Creates a new {@link Set} backed by a ConcurrentHashMapV8 from the given
  	 * type to {@code Boolean.TRUE}.
  	 *
  	 * @return the new set
  	 */
  	public static <K> KeySetView<K, Boolean> newKeySet() {
  		return new KeySetView<K, Boolean>(new ConcurrentHashMapV8<K, Boolean>(), Boolean.TRUE);
  	}
  
  	/**
  	 * Creates a new {@link Set} backed by a ConcurrentHashMapV8 from the given
  	 * type to {@code Boolean.TRUE}.
  	 *
  	 * @param initialCapacity
  	 *            The implementation performs internal sizing to accommodate
  	 *            this many elements.
  	 * @throws IllegalArgumentException
  	 *             if the initial capacity of elements is negative
  	 * @return the new set
  	 */
  	public static <K> KeySetView<K, Boolean> newKeySet(int initialCapacity) {
  		return new KeySetView<K, Boolean>(new ConcurrentHashMapV8<K, Boolean>(initialCapacity), Boolean.TRUE);
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public boolean isEmpty() {
  		return sumCount() <= 0L; // ignore transient negative values
  	}
  
  	/**
  	 * {@inheritDoc}
  	 */
  	@Override
  	public int size() {
  		long n = sumCount();
  		return ((n < 0L) ? 0 : (n > Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int) n);
  	}
  
  	/**
  	 * Returns the number of mappings. This method should be used instead of
  	 * {@link #size} because a ConcurrentHashMapV8 may contain more mappings
  	 * than can be represented as an int. The value returned is an estimate; the
  	 * actual count may differ if there are concurrent insertions or removals.
  	 *
  	 * @return the number of mappings
  	 */
  	public long mappingCount() {
  		long n = sumCount();
  		return (n < 0L) ? 0L : n; // ignore transient negative values
  	}
  
  	/**
  	 * Returns the value to which the specified key is mapped, or {@code null}
  	 * if this map contains no mapping for the key.
  	 *
  	 * <p>
  	 * More formally, if this map contains a mapping from a key {@code k} to a
  	 * value {@code v} such that {@code key.equals(k)}, then this method returns
  	 * {@code v}; otherwise it returns {@code null}. (There can be at most one
  	 * such mapping.)
  	 *
  	 * @throws NullPointerException
  	 *             if the specified key is null
  	 */
  	@Override
  	public V get(Object key) {
  		return internalGet(key);
  	}
  
  	/**
  	 * Returns the value to which the specified key is mapped, or the given
  	 * defaultValue if this map contains no mapping for the key.
  	 *
  	 * @param key
  	 *            the key
  	 * @param defaultValue
  	 *            the value to return if this map contains no mapping for the
  	 *            given key
  	 * @return the mapping for the key, if present; else the defaultValue
  	 * @throws NullPointerException
  	 *             if the specified key is null
  	 */
  	public V getValueOrDefault(Object key, V defaultValue) {
  		V v;
  		return (v = internalGet(key)) == null ? defaultValue : v;
  	}
  
  	/**
  	 * Tests if the specified object is a key in this table.
  	 *
  	 * @param key
  	 *            possible key
  	 * @return {@code true} if and only if the specified object is a key in this
  	 *         table, as determined by the {@code equals} method; {@code false}
  	 *         otherwise
  	 * @throws NullPointerException
  	 *             if the specified key is null
  	 */
  	@Override
  	public boolean containsKey(Object key) {
  		return internalGet(key) != null;
  	}
  
  	/**
  	 * Returns {@code true} if this map maps one or more keys to the specified
  	 * value. Note: This method may require a full traversal of the map, and is
  	 * much slower than method {@code containsKey}.
  	 *
  	 * @param value
  	 *            value whose presence in this map is to be tested
  	 * @return {@code true} if this map maps one or more keys to the specified
  	 *         value
  	 * @throws NullPointerException
  	 *             if the specified value is null
  	 */
  	@Override
  	public boolean containsValue(Object value) {
  		if (value == null)
  			throw new NullPointerException();
  		V v;
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		while ((v = it.advance()) != null) {
  			if (v == value || value.equals(v))
  				return true;
  		}
  		return false;
  	}
  
  	/**
  	 * Legacy method testing if some key maps into the specified value in this
  	 * table. This method is identical in functionality to
  	 * {@link #containsValue}, and exists solely to ensure full compatibility
  	 * with class {@link java.util.Hashtable}, which supported this method prior
  	 * to introduction of the Java Collections framework.
  	 *
  	 * @param value
  	 *            a value to search for
  	 * @return {@code true} if and only if some key maps to the {@code value}
  	 *         argument in this table as determined by the {@code equals}
  	 *         method; {@code false} otherwise
  	 * @throws NullPointerException
  	 *             if the specified value is null
  	 */
  	@Deprecated
  	public boolean contains(Object value) {
  		return containsValue(value);
  	}
  
  	/**
  	 * Maps the specified key to the specified value in this table. Neither the
  	 * key nor the value can be null.
  	 *
  	 * <p>
  	 * The value can be retrieved by calling the {@code get} method with a key
  	 * that is equal to the original key.
  	 *
  	 * @param key
  	 *            key with which the specified value is to be associated
  	 * @param value
  	 *            value to be associated with the specified key
  	 * @return the previous value associated with {@code key}, or {@code null}
  	 *         if there was no mapping for {@code key}
  	 * @throws NullPointerException
  	 *             if the specified key or value is null
  	 */
  	@Override
  	public V put(K key, V value) {
  		return internalPut(key, value, false);
  	}
  
  	/**
  	 * {@inheritDoc}
  	 *
  	 * @return the previous value associated with the specified key, or
  	 *         {@code null} if there was no mapping for the key
  	 * @throws NullPointerException
  	 *             if the specified key or value is null
  	 */
  	@Override
  	public V putIfAbsent(K key, V value) {
  		return internalPut(key, value, true);
  	}
  
  	/**
  	 * Copies all of the mappings from the specified map to this one. These
  	 * mappings replace any mappings that this map had for any of the keys
  	 * currently in the specified map.
  	 *
  	 * @param m
  	 *            mappings to be stored in this map
  	 */
  	@Override
  	public void putAll(Map<? extends K, ? extends V> m) {
  		internalPutAll(m);
  	}
  
  	/**
  	 * If the specified key is not already associated with a value, computes its
  	 * value using the given mappingFunction and enters it into the map unless
  	 * null. This is equivalent to
  	 * 
  	 * <pre>
  	 *  {@code
  	 * if (map.containsKey(key))
  	 *   return map.get(key);
  	 * value = mappingFunction.apply(key);
  	 * if (value != null)
  	 *   map.put(key, value);
  	 * return value;}
  	 * </pre>
  	 *
  	 * except that the action is performed atomically. If the function returns
  	 * {@code null} no mapping is recorded. If the function itself throws an
  	 * (unchecked) exception, the exception is rethrown to its caller, and no
  	 * mapping is recorded. Some attempted update operations on this map by
  	 * other threads may be blocked while computation is in progress, so the
  	 * computation should be short and simple, and must not attempt to update
  	 * any other mappings of this Map. The most appropriate usage is to
  	 * construct a new object serving as an initial mapped value, or memoized
  	 * result, as in:
  	 *
  	 * <pre>
  	 *  {@code
  	 * map.computeIfAbsent(key, new Fun<K,V>() {
  	 *   public V map(K k) { return new Value(f(k)); }});}
  	 * </pre>
  	 *
  	 * @param key
  	 *            key with which the specified value is to be associated
  	 * @param mappingFunction
  	 *            the function to compute a value
  	 * @return the current (existing or computed) value associated with the
  	 *         specified key, or null if the computed value is null
  	 * @throws NullPointerException
  	 *             if the specified key or mappingFunction is null
  	 * @throws IllegalStateException
  	 *             if the computation detectably attempts a recursive update to
  	 *             this map that would otherwise never complete
  	 * @throws RuntimeException
  	 *             or Error if the mappingFunction does so, in which case the
  	 *             mapping is left unestablished
  	 */
  	public V computeIfAbsent(K key, Fun<? super K, ? extends V> mappingFunction) {
  		return internalComputeIfAbsent(key, mappingFunction);
  	}
  
  	/**
  	 * If the given key is present, computes a new mapping value given a key and
  	 * its current mapped value. This is equivalent to
  	 * 
  	 * <pre>
  	 *  {@code
  	 *   if (map.containsKey(key)) {
  	 *     value = remappingFunction.apply(key, map.get(key));
  	 *     if (value != null)
  	 *       map.put(key, value);
  	 *     else
  	 *       map.remove(key);
  	 *   }
  	 * }
  	 * </pre>
  	 *
  	 * except that the action is performed atomically. If the function returns
  	 * {@code null}, the mapping is removed. If the function itself throws an
  	 * (unchecked) exception, the exception is rethrown to its caller, and the
  	 * current mapping is left unchanged. Some attempted update operations on
  	 * this map by other threads may be blocked while computation is in
  	 * progress, so the computation should be short and simple, and must not
  	 * attempt to update any other mappings of this Map. For example, to either
  	 * create or append new messages to a value mapping:
  	 *
  	 * @param key
  	 *            key with which the specified value is to be associated
  	 * @param remappingFunction
  	 *            the function to compute a value
  	 * @return the new value associated with the specified key, or null if none
  	 * @throws NullPointerException
  	 *             if the specified key or remappingFunction is null
  	 * @throws IllegalStateException
  	 *             if the computation detectably attempts a recursive update to
  	 *             this map that would otherwise never complete
  	 * @throws RuntimeException
  	 *             or Error if the remappingFunction does so, in which case the
  	 *             mapping is unchanged
  	 */
  	public V computeIfPresent(K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
  		return internalCompute(key, true, remappingFunction);
  	}
  
  	/**
  	 * Computes a new mapping value given a key and its current mapped value (or
  	 * {@code null} if there is no current mapping). This is equivalent to
  	 * 
  	 * <pre>
  	 *  {@code
  	 *   value = remappingFunction.apply(key, map.get(key));
  	 *   if (value != null)
  	 *     map.put(key, value);
  	 *   else
  	 *     map.remove(key);
  	 * }
  	 * </pre>
  	 *
  	 * except that the action is performed atomically. If the function returns
  	 * {@code null}, the mapping is removed. If the function itself throws an
  	 * (unchecked) exception, the exception is rethrown to its caller, and the
  	 * current mapping is left unchanged. Some attempted update operations on
  	 * this map by other threads may be blocked while computation is in
  	 * progress, so the computation should be short and simple, and must not
  	 * attempt to update any other mappings of this Map. For example, to either
  	 * create or append new messages to a value mapping:
  	 *
  	 * <pre>
  	 *  {@code
  	 * Map<Key, String> map = ...;
  	 * final String msg = ...;
  	 * map.compute(key, new BiFun<Key, String, String>() {
  	 *   public String apply(Key k, String v) {
  	 *    return (v == null) ? msg : v + msg;});}}
  	 * </pre>
  	 *
  	 * @param key
  	 *            key with which the specified value is to be associated
  	 * @param remappingFunction
  	 *            the function to compute a value
  	 * @return the new value associated with the specified key, or null if none
  	 * @throws NullPointerException
  	 *             if the specified key or remappingFunction is null
  	 * @throws IllegalStateException
  	 *             if the computation detectably attempts a recursive update to
  	 *             this map that would otherwise never complete
  	 * @throws RuntimeException
  	 *             or Error if the remappingFunction does so, in which case the
  	 *             mapping is unchanged
  	 */
  	public V compute(K key, BiFun<? super K, ? super V, ? extends V> remappingFunction) {
  		return internalCompute(key, false, remappingFunction);
  	}
  
  	/**
  	 * If the specified key is not already associated with a value, associate it
  	 * with the given value. Otherwise, replace the value with the results of
  	 * the given remapping function. This is equivalent to:
  	 * 
  	 * <pre>
  	 *  {@code
  	 *   if (!map.containsKey(key))
  	 *     map.put(value);
  	 *   else {
  	 *     newValue = remappingFunction.apply(map.get(key), value);
  	 *     if (value != null)
  	 *       map.put(key, value);
  	 *     else
  	 *       map.remove(key);
  	 *   }
  	 * }
  	 * </pre>
  	 * 
  	 * except that the action is performed atomically. If the function returns
  	 * {@code null}, the mapping is removed. If the function itself throws an
  	 * (unchecked) exception, the exception is rethrown to its caller, and the
  	 * current mapping is left unchanged. Some attempted update operations on
  	 * this map by other threads may be blocked while computation is in
  	 * progress, so the computation should be short and simple, and must not
  	 * attempt to update any other mappings of this Map.
  	 */
  	public V merge(K key, V value, BiFun<? super V, ? super V, ? extends V> remappingFunction) {
  		return internalMerge(key, value, remappingFunction);
  	}
  
  	/**
  	 * Removes the key (and its corresponding value) from this map. This method
  	 * does nothing if the key is not in the map.
  	 *
  	 * @param key
  	 *            the key that needs to be removed
  	 * @return the previous value associated with {@code key}, or {@code null}
  	 *         if there was no mapping for {@code key}
  	 * @throws NullPointerException
  	 *             if the specified key is null
  	 */
  	@Override
  	public V remove(Object key) {
  		return internalReplace(key, null, null);
  	}
  
  	/**
  	 * {@inheritDoc}
  	 *
  	 * @throws NullPointerException
  	 *             if the specified key is null
  	 */
  	@Override
  	public boolean remove(Object key, Object value) {
  		return value != null && internalReplace(key, null, value) != null;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 *
  	 * @throws NullPointerException
  	 *             if any of the arguments are null
  	 */
  	@Override
  	public boolean replace(K key, V oldValue, V newValue) {
  		if (key == null || oldValue == null || newValue == null)
  			throw new NullPointerException();
  		return internalReplace(key, newValue, oldValue) != null;
  	}
  
  	/**
  	 * {@inheritDoc}
  	 *
  	 * @return the previous value associated with the specified key, or
  	 *         {@code null} if there was no mapping for the key
  	 * @throws NullPointerException
  	 *             if the specified key or value is null
  	 */
  	@Override
  	public V replace(K key, V value) {
  		if (key == null || value == null)
  			throw new NullPointerException();
  		return internalReplace(key, value, null);
  	}
  
  	/**
  	 * Removes all of the mappings from this map.
  	 */
  	@Override
  	public void clear() {
  		internalClear();
  	}
  
  	/**
  	 * Returns a {@link Set} view of the keys contained in this map. The set is
  	 * backed by the map, so changes to the map are reflected in the set, and
  	 * vice-versa.
  	 *
  	 * @return the set view
  	 */
  	@Override
  	public KeySetView<K, V> keySet() {
  		KeySetView<K, V> ks = keySet;
  		return (ks != null) ? ks : (keySet = new KeySetView<K, V>(this, null));
  	}
  
  	/**
  	 * Returns a {@link Set} view of the keys in this map, using the given
  	 * common mapped value for any additions (i.e., {@link Collection#add} and
  	 * {@link Collection#addAll}). This is of course only appropriate if it is
  	 * acceptable to use the same value for all additions from this view.
  	 *
  	 * @param mappedValue
  	 *            the mapped value to use for any additions
  	 * @return the set view
  	 * @throws NullPointerException
  	 *             if the mappedValue is null
  	 */
  	public KeySetView<K, V> keySet(V mappedValue) {
  		if (mappedValue == null)
  			throw new NullPointerException();
  		return new KeySetView<K, V>(this, mappedValue);
  	}
  
  	/**
  	 * Returns a {@link Collection} view of the values contained in this map.
  	 * The collection is backed by the map, so changes to the map are reflected
  	 * in the collection, and vice-versa.
  	 */
  	@Override
  	public ValuesView<K, V> values() {
  		ValuesView<K, V> vs = values;
  		return (vs != null) ? vs : (values = new ValuesView<K, V>(this));
  	}
  
  	/**
  	 * Returns a {@link Set} view of the mappings contained in this map. The set
  	 * is backed by the map, so changes to the map are reflected in the set, and
  	 * vice-versa. The set supports element removal, which removes the
  	 * corresponding mapping from the map, via the {@code Iterator.remove},
  	 * {@code Set.remove}, {@code removeAll}, {@code retainAll}, and
  	 * {@code clear} operations. It does not support the {@code add} or
  	 * {@code addAll} operations.
  	 *
  	 * <p>
  	 * The view's {@code iterator} is a "weakly consistent" iterator that will
  	 * never throw {@link ConcurrentModificationException}, and guarantees to
  	 * traverse elements as they existed upon construction of the iterator, and
  	 * may (but is not guaranteed to) reflect any modifications subsequent to
  	 * construction.
  	 */
  	@Override
  	public Set<Map.Entry<K, V>> entrySet() {
  		EntrySetView<K, V> es = entrySet;
  		return (es != null) ? es : (entrySet = new EntrySetView<K, V>(this));
  	}
  
  	/**
  	 * Returns an enumeration of the keys in this table.
  	 *
  	 * @return an enumeration of the keys in this table
  	 * @see #keySet()
  	 */
  	public Enumeration<K> keys() {
  		return new KeyIterator<K, V>(this);
  	}
  
  	/**
  	 * Returns an enumeration of the values in this table.
  	 *
  	 * @return an enumeration of the values in this table
  	 * @see #values()
  	 */
  	public Enumeration<V> elements() {
  		return new ValueIterator<K, V>(this);
  	}
  
  	/**
  	 * Returns a partitionable iterator of the keys in this map.
  	 *
  	 * @return a partitionable iterator of the keys in this map
  	 */
  	public Spliterator<K> keySpliterator() {
  		return new KeyIterator<K, V>(this);
  	}
  
  	/**
  	 * Returns a partitionable iterator of the values in this map.
  	 *
  	 * @return a partitionable iterator of the values in this map
  	 */
  	public Spliterator<V> valueSpliterator() {
  		return new ValueIterator<K, V>(this);
  	}
  
  	/**
  	 * Returns a partitionable iterator of the entries in this map.
  	 *
  	 * @return a partitionable iterator of the entries in this map
  	 */
  	public Spliterator<Map.Entry<K, V>> entrySpliterator() {
  		return new EntryIterator<K, V>(this);
  	}
  
  	/**
  	 * Returns the hash code value for this {@link Map}, i.e., the sum of, for
  	 * each key-value pair in the map,
  	 * {@code key.hashCode() ^ value.hashCode()}.
  	 *
  	 * @return the hash code value for this map
  	 */
  	@Override
  	public int hashCode() {
  		int h = 0;
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		while ((v = it.advance()) != null) {
  			h += it.nextKey.hashCode() ^ v.hashCode();
  		}
  		return h;
  	}
  
  	/**
  	 * Returns a string representation of this map. The string representation
  	 * consists of a list of key-value mappings (in no particular order)
  	 * enclosed in braces ("{@code {}}"). Adjacent mappings are separated by the
  	 * characters {@code ", "} (comma and space). Each key-value mapping is
  	 * rendered as the key followed by an equals sign ("{@code =}") followed by
  	 * the associated value.
  	 *
  	 * @return a string representation of this map
  	 */
  	@Override
  	public String toString() {
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		StringBuilder sb = new StringBuilder();
  		sb.append('{');
  		V v;
  		if ((v = it.advance()) != null) {
  			for (;;) {
  				Object k = it.nextKey;
  				sb.append(k == this ? "(this Map)" : k);
  				sb.append('=');
  				sb.append(v == this ? "(this Map)" : v);
  				if ((v = it.advance()) == null)
  					break;
  				sb.append(',').append(' ');
  			}
  		}
  		return sb.append('}').toString();
  	}
  
  	/**
  	 * Compares the specified object with this map for equality. Returns
  	 * {@code true} if the given object is a map with the same mappings as this
  	 * map. This operation may return misleading results if either map is
  	 * concurrently modified during execution of this method.
  	 *
  	 * @param o
  	 *            object to be compared for equality with this map
  	 * @return {@code true} if the specified object is equal to this map
  	 */
  	@Override
  	public boolean equals(Object o) {
  		if (o != this) {
  			if (!(o instanceof Map))
  				return false;
  			Map<?, ?> m = (Map<?, ?>) o;
  			Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  			V val;
  			while ((val = it.advance()) != null) {
  				Object v = m.get(it.nextKey);
  				if (v == null || (v != val && !v.equals(val)))
  					return false;
  			}
  			for (Map.Entry<?, ?> e : m.entrySet()) {
  				Object mk, mv, v;
  				if ((mk = e.getKey()) == null || (mv = e.getValue()) == null || (v = internalGet(mk)) == null
  						|| (mv != v && !mv.equals(v)))
  					return false;
  			}
  		}
  		return true;
  	}
  
  	/* ----------------Iterators -------------- */
  	@SuppressWarnings("serial")
  	static final class KeyIterator<K, V> extends Traverser<K, V, Object> implements Spliterator<K>, Enumeration<K> {
  
  		KeyIterator(ConcurrentHashMapV8<K, V> map) {
  			super(map);
  		}
  
  		KeyIterator(ConcurrentHashMapV8<K, V> map, Traverser<K, V, Object> it) {
  			super(map, it, -1);
  		}
  
  		@Override
  		public KeyIterator<K, V> split() {
  			if (nextKey != null)
  				throw new IllegalStateException();
  			return new KeyIterator<K, V>(map, this);
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final K next() {
  			if (nextVal == null && advance() == null)
  				throw new NoSuchElementException();
  			Object k = nextKey;
  			nextVal = null;
  			return (K) k;
  		}
  
  		@Override
  		public final K nextElement() {
  			return next();
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ValueIterator<K, V> extends Traverser<K, V, Object> implements Spliterator<V>, Enumeration<V> {
  
  		ValueIterator(ConcurrentHashMapV8<K, V> map) {
  			super(map);
  		}
  
  		ValueIterator(ConcurrentHashMapV8<K, V> map, Traverser<K, V, Object> it) {
  			super(map, it, -1);
  		}
  
  		@Override
  		public ValueIterator<K, V> split() {
  			if (nextKey != null)
  				throw new IllegalStateException();
  			return new ValueIterator<K, V>(map, this);
  		}
  
  		@Override
  		public final V next() {
  			V v;
  			if ((v = nextVal) == null && (v = advance()) == null)
  				throw new NoSuchElementException();
  			nextVal = null;
  			return v;
  		}
  
  		@Override
  		public final V nextElement() {
  			return next();
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class EntryIterator<K, V> extends Traverser<K, V, Object> implements Spliterator<Map.Entry<K, V>> {
  
  		EntryIterator(ConcurrentHashMapV8<K, V> map) {
  			super(map);
  		}
  
  		EntryIterator(ConcurrentHashMapV8<K, V> map, Traverser<K, V, Object> it) {
  			super(map, it, -1);
  		}
  
  		@Override
  		public EntryIterator<K, V> split() {
  			if (nextKey != null)
  				throw new IllegalStateException();
  			return new EntryIterator<K, V>(map, this);
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final Map.Entry<K, V> next() {
  			V v;
  			if ((v = nextVal) == null && (v = advance()) == null)
  				throw new NoSuchElementException();
  			Object k = nextKey;
  			nextVal = null;
  			return new MapEntry<K, V>((K) k, v, map);
  		}
  	}
  
  	/**
  	 * Exported Entry for iterators
  	 */
  	static final class MapEntry<K, V> implements Map.Entry<K, V> {
  
  		final K key; // non-null
  		V val; // non-null
  		final ConcurrentHashMapV8<K, V> map;
  
  		MapEntry(K key, V val, ConcurrentHashMapV8<K, V> map) {
  			this.key = key;
  			this.val = val;
  			this.map = map;
  		}
  
  		@Override
  		public final K getKey() {
  			return key;
  		}
  
  		@Override
  		public final V getValue() {
  			return val;
  		}
  
  		@Override
  		public final int hashCode() {
  			return key.hashCode() ^ val.hashCode();
  		}
  
  		@Override
  		public final String toString() {
  			return key + "=" + val;
  		}
  
  		@Override
  		public final boolean equals(Object o) {
  			Object k, v;
  			Map.Entry<?, ?> e;
  			return ((o instanceof Map.Entry) && (k = (e = (Map.Entry<?, ?>) o).getKey()) != null
  					&& (v = e.getValue()) != null && (k == key || k.equals(key)) && (v == val || v.equals(val)));
  		}
  
  		/**
  		 * Sets our entry's value and writes through to the map. The value to
  		 * return is somewhat arbitrary here. Since we do not necessarily track
  		 * asynchronous changes, the most recent "previous" value could be
  		 * different from what we return (or could even have been removed in
  		 * which case the put will re-establish). We do not and cannot guarantee
  		 * more.
  		 */
  		@Override
  		public final V setValue(V value) {
  			if (value == null)
  				throw new NullPointerException();
  			V v = val;
  			val = value;
  			map.put(key, value);
  			return v;
  		}
  	}
  
  	/**
  	 * Returns exportable snapshot entry for the given key and value when
  	 * write-through can't or shouldn't be used.
  	 */
  	static <K, V> AbstractMap.SimpleEntry<K, V> entryFor(K k, V v) {
  		return new AbstractMap.SimpleEntry<K, V>(k, v);
  	}
  
  	/* ---------------- Serialization Support -------------- */
  	/**
  	 * Stripped-down version of helper class used in previous version, declared
  	 * for the sake of serialization compatibility
  	 */
  	static class Segment<K, V> implements Serializable {
  
  		private static final long serialVersionUID = 2249069246763182397L;
  		final float loadFactor;
  
  		Segment(float lf) {
  			this.loadFactor = lf;
  		}
  	}
  
  	/**
  	 * Saves the state of the {@code ConcurrentHashMapV8} instance to a stream
  	 * (i.e., serializes it).
  	 *
  	 * @param s
  	 *            the stream
  	 * @serialData the key (Object) and value (Object) for each key-value
  	 *             mapping, followed by a null pair. The key-value mappings are
  	 *             emitted in no particular order.
  	 */
  	@SuppressWarnings("unchecked")
  	private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
  		if (segments == null) { // for serialization compatibility
  			segments = (Segment<K, V>[]) new Segment<?, ?>[DEFAULT_CONCURRENCY_LEVEL];
  			for (int i = 0; i < segments.length; ++i)
  				segments[i] = new Segment<K, V>(LOAD_FACTOR);
  		}
  		s.defaultWriteObject();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		while ((v = it.advance()) != null) {
  			s.writeObject(it.nextKey);
  			s.writeObject(v);
  		}
  		s.writeObject(null);
  		s.writeObject(null);
  		segments = null; // throw away
  	}
  
  	/**
  	 * Reconstitutes the instance from a stream (that is, deserializes it).
  	 *
  	 * @param s
  	 *            the stream
  	 */
  	@SuppressWarnings("unchecked")
  	private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException {
  		s.defaultReadObject();
  		this.segments = null; // unneeded
  
  		// Create all nodes, then place in table once size is known
  		long size = 0L;
  		Node<V> p = null;
  		for (;;) {
  			K k = (K) s.readObject();
  			V v = (V) s.readObject();
  			if (k != null && v != null) {
  				int h = spread(k.hashCode());
  				p = new Node<V>(h, k, v, p);
  				++size;
  			} else
  				break;
  		}
  		if (p != null) {
  			boolean init = false;
  			int n;
  			if (size >= MAXIMUM_CAPACITY >>> 1)
  				n = MAXIMUM_CAPACITY;
  			else {
  				int sz = (int) size;
  				n = tableSizeFor(sz + (sz >>> 1) + 1);
  			}
  			int sc = sizeCtl;
  			boolean collide = false;
  			if (n > sc && U.compareAndSwapInt(this, SIZECTL, sc, -1)) {
  				try {
  					if (table == null) {
  						init = true;
  						@SuppressWarnings("rawtypes")
  						Node[] rt = new Node[n];
  						Node<V>[] tab = rt;
  						int mask = n - 1;
  						while (p != null) {
  							int j = p.hash & mask;
  							Node<V> next = p.next;
  							Node<V> q = p.next = tabAt(tab, j);
  							setTabAt(tab, j, p);
  							if (!collide && q != null && q.hash == p.hash)
  								collide = true;
  							p = next;
  						}
  						table = tab;
  						addCount(size, -1);
  						sc = n - (n >>> 2);
  					}
  				} finally {
  					sizeCtl = sc;
  				}
  				if (collide) { // rescan and convert to TreeBins
  					Node<V>[] tab = table;
  					for (int i = 0; i < tab.length; ++i) {
  						int c = 0;
  						for (Node<V> e = tabAt(tab, i); e != null; e = e.next) {
  							if (++c > TREE_THRESHOLD && (e.key instanceof Comparable)) {
  								replaceWithTreeBin(tab, i, e.key);
  								break;
  							}
  						}
  					}
  				}
  			}
  			if (!init) { // Can only happen if unsafely published.
  				while (p != null) {
  					internalPut((K) p.key, p.val, false);
  					p = p.next;
  				}
  			}
  		}
  	}
  
  	// -------------------------------------------------------
  	// Sams
  	/**
  	 * Interface describing a void action of one argument
  	 */
  	public interface Action<A> {
  
  		void apply(A a);
  	}
  
  	/**
  	 * Interface describing a void action of two arguments
  	 */
  	public interface BiAction<A, B> {
  
  		void apply(A a, B b);
  	}
  
  	/**
  	 * Interface describing a function of one argument
  	 */
  	public interface Fun<A, T> {
  
  		T apply(A a);
  	}
  
  	/**
  	 * Interface describing a function of two arguments
  	 */
  	public interface BiFun<A, B, T> {
  
  		T apply(A a, B b);
  	}
  
  	/**
  	 * Interface describing a function of no arguments
  	 */
  	public interface Generator<T> {
  
  		T apply();
  	}
  
  	/**
  	 * Interface describing a function mapping its argument to a double
  	 */
  	public interface ObjectToDouble<A> {
  
  		double apply(A a);
  	}
  
  	/**
  	 * Interface describing a function mapping its argument to a long
  	 */
  	public interface ObjectToLong<A> {
  
  		long apply(A a);
  	}
  
  	/**
  	 * Interface describing a function mapping its argument to an int
  	 */
  	public interface ObjectToInt<A> {
  
  		int apply(A a);
  	}
  
  	/**
  	 * Interface describing a function mapping two arguments to a double
  	 */
  	public interface ObjectByObjectToDouble<A, B> {
  
  		double apply(A a, B b);
  	}
  
  	/**
  	 * Interface describing a function mapping two arguments to a long
  	 */
  	public interface ObjectByObjectToLong<A, B> {
  
  		long apply(A a, B b);
  	}
  
  	/**
  	 * Interface describing a function mapping two arguments to an int
  	 */
  	public interface ObjectByObjectToInt<A, B> {
  
  		int apply(A a, B b);
  	}
  
  	/**
  	 * Interface describing a function mapping a double to a double
  	 */
  	public interface DoubleToDouble {
  
  		double apply(double a);
  	}
  
  	/**
  	 * Interface describing a function mapping a long to a long
  	 */
  	public interface LongToLong {
  
  		long apply(long a);
  	}
  
  	/**
  	 * Interface describing a function mapping an int to an int
  	 */
  	public interface IntToInt {
  
  		int apply(int a);
  	}
  
  	/**
  	 * Interface describing a function mapping two doubles to a double
  	 */
  	public interface DoubleByDoubleToDouble {
  
  		double apply(double a, double b);
  	}
  
  	/**
  	 * Interface describing a function mapping two longs to a long
  	 */
  	public interface LongByLongToLong {
  
  		long apply(long a, long b);
  	}
  
  	/**
  	 * Interface describing a function mapping two ints to an int
  	 */
  	public interface IntByIntToInt {
  
  		int apply(int a, int b);
  	}
  
  	// -------------------------------------------------------
  	// Sequential bulk operations
  	/**
  	 * Performs the given action for each (key, value).
  	 *
  	 * @param action
  	 *            the action
  	 */
  	@SuppressWarnings("unchecked")
  	public void forEachSequentially(BiAction<K, V> action) {
  		if (action == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		while ((v = it.advance()) != null)
  			action.apply((K) it.nextKey, v);
  	}
  
  	/**
  	 * Performs the given action for each non-null transformation of each (key,
  	 * value).
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case the action
  	 *            is not applied)
  	 * @param action
  	 *            the action
  	 */
  	@SuppressWarnings("unchecked")
  	public <U> void forEachSequentially(BiFun<? super K, ? super V, ? extends U> transformer, Action<U> action) {
  		if (transformer == null || action == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		U u;
  		while ((v = it.advance()) != null) {
  			if ((u = transformer.apply((K) it.nextKey, v)) != null)
  				action.apply(u);
  		}
  	}
  
  	/**
  	 * Returns a non-null result from applying the given search function on each
  	 * (key, value), or null if none.
  	 *
  	 * @param searchFunction
  	 *            a function returning a non-null result on success, else null
  	 * @return a non-null result from applying the given search function on each
  	 *         (key, value), or null if none
  	 */
  	@SuppressWarnings("unchecked")
  	public <U> U searchSequentially(BiFun<? super K, ? super V, ? extends U> searchFunction) {
  		if (searchFunction == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		U u;
  		while ((v = it.advance()) != null) {
  			if ((u = searchFunction.apply((K) it.nextKey, v)) != null)
  				return u;
  		}
  		return null;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all (key,
  	 * value) pairs using the given reducer to combine values, or null if none.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case it is not
  	 *            combined)
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all (key,
  	 *         value) pairs
  	 */
  	@SuppressWarnings("unchecked")
  	public <U> U reduceSequentially(BiFun<? super K, ? super V, ? extends U> transformer,
  			BiFun<? super U, ? super U, ? extends U> reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		U r = null, u;
  		V v;
  		while ((v = it.advance()) != null) {
  			if ((u = transformer.apply((K) it.nextKey, v)) != null)
  				r = (r == null) ? u : reducer.apply(r, u);
  		}
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all (key,
  	 * value) pairs using the given reducer to combine values, and the given
  	 * basis as an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all (key,
  	 *         value) pairs
  	 */
  	@SuppressWarnings("unchecked")
  	public double reduceToDoubleSequentially(ObjectByObjectToDouble<? super K, ? super V> transformer, double basis,
  			DoubleByDoubleToDouble reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		double r = basis;
  		V v;
  		while ((v = it.advance()) != null)
  			r = reducer.apply(r, transformer.apply((K) it.nextKey, v));
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all (key,
  	 * value) pairs using the given reducer to combine values, and the given
  	 * basis as an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all (key,
  	 *         value) pairs
  	 */
  	@SuppressWarnings("unchecked")
  	public long reduceToLongSequentially(ObjectByObjectToLong<? super K, ? super V> transformer, long basis,
  			LongByLongToLong reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		long r = basis;
  		V v;
  		while ((v = it.advance()) != null)
  			r = reducer.apply(r, transformer.apply((K) it.nextKey, v));
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all (key,
  	 * value) pairs using the given reducer to combine values, and the given
  	 * basis as an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all (key,
  	 *         value) pairs
  	 */
  	@SuppressWarnings("unchecked")
  	public int reduceToIntSequentially(ObjectByObjectToInt<? super K, ? super V> transformer, int basis,
  			IntByIntToInt reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		int r = basis;
  		V v;
  		while ((v = it.advance()) != null)
  			r = reducer.apply(r, transformer.apply((K) it.nextKey, v));
  		return r;
  	}
  
  	/**
  	 * Performs the given action for each key.
  	 *
  	 * @param action
  	 *            the action
  	 */
  	@SuppressWarnings("unchecked")
  	public void forEachKeySequentially(Action<K> action) {
  		if (action == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		while (it.advance() != null)
  			action.apply((K) it.nextKey);
  	}
  
  	/**
  	 * Performs the given action for each non-null transformation of each key.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case the action
  	 *            is not applied)
  	 * @param action
  	 *            the action
  	 */
  	@SuppressWarnings("unchecked")
  	public <U> void forEachKeySequentially(Fun<? super K, ? extends U> transformer, Action<U> action) {
  		if (transformer == null || action == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		U u;
  		while (it.advance() != null) {
  			if ((u = transformer.apply((K) it.nextKey)) != null)
  				action.apply(u);
  		}
  		ForkJoinTasks.forEachKey(this, transformer, action).invoke();
  	}
  
  	/**
  	 * Returns a non-null result from applying the given search function on each
  	 * key, or null if none.
  	 *
  	 * @param searchFunction
  	 *            a function returning a non-null result on success, else null
  	 * @return a non-null result from applying the given search function on each
  	 *         key, or null if none
  	 */
  	@SuppressWarnings("unchecked")
  	public <U> U searchKeysSequentially(Fun<? super K, ? extends U> searchFunction) {
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		U u;
  		while (it.advance() != null) {
  			if ((u = searchFunction.apply((K) it.nextKey)) != null)
  				return u;
  		}
  		return null;
  	}
  
  	/**
  	 * Returns the result of accumulating all keys using the given reducer to
  	 * combine values, or null if none.
  	 *
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating all keys using the given reducer to
  	 *         combine values, or null if none
  	 */
  	@SuppressWarnings("unchecked")
  	public K reduceKeysSequentially(BiFun<? super K, ? super K, ? extends K> reducer) {
  		if (reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		K r = null;
  		while (it.advance() != null) {
  			K u = (K) it.nextKey;
  			r = (r == null) ? u : reducer.apply(r, u);
  		}
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all keys
  	 * using the given reducer to combine values, or null if none.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case it is not
  	 *            combined)
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all keys
  	 */
  	@SuppressWarnings("unchecked")
  	public <U> U reduceKeysSequentially(Fun<? super K, ? extends U> transformer,
  			BiFun<? super U, ? super U, ? extends U> reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		U r = null, u;
  		while (it.advance() != null) {
  			if ((u = transformer.apply((K) it.nextKey)) != null)
  				r = (r == null) ? u : reducer.apply(r, u);
  		}
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all keys
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all keys
  	 */
  	@SuppressWarnings("unchecked")
  	public double reduceKeysToDoubleSequentially(ObjectToDouble<? super K> transformer, double basis,
  			DoubleByDoubleToDouble reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		double r = basis;
  		while (it.advance() != null)
  			r = reducer.apply(r, transformer.apply((K) it.nextKey));
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all keys
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all keys
  	 */
  	@SuppressWarnings("unchecked")
  	public long reduceKeysToLongSequentially(ObjectToLong<? super K> transformer, long basis,
  			LongByLongToLong reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		long r = basis;
  		while (it.advance() != null)
  			r = reducer.apply(r, transformer.apply((K) it.nextKey));
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all keys
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all keys
  	 */
  	@SuppressWarnings("unchecked")
  	public int reduceKeysToIntSequentially(ObjectToInt<? super K> transformer, int basis, IntByIntToInt reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		int r = basis;
  		while (it.advance() != null)
  			r = reducer.apply(r, transformer.apply((K) it.nextKey));
  		return r;
  	}
  
  	/**
  	 * Performs the given action for each value.
  	 *
  	 * @param action
  	 *            the action
  	 */
  	public void forEachValueSequentially(Action<V> action) {
  		if (action == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		while ((v = it.advance()) != null)
  			action.apply(v);
  	}
  
  	/**
  	 * Performs the given action for each non-null transformation of each value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case the action
  	 *            is not applied)
  	 */
  	public <U> void forEachValueSequentially(Fun<? super V, ? extends U> transformer, Action<U> action) {
  		if (transformer == null || action == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		U u;
  		while ((v = it.advance()) != null) {
  			if ((u = transformer.apply(v)) != null)
  				action.apply(u);
  		}
  	}
  
  	/**
  	 * Returns a non-null result from applying the given search function on each
  	 * value, or null if none.
  	 *
  	 * @param searchFunction
  	 *            a function returning a non-null result on success, else null
  	 * @return a non-null result from applying the given search function on each
  	 *         value, or null if none
  	 */
  	public <U> U searchValuesSequentially(Fun<? super V, ? extends U> searchFunction) {
  		if (searchFunction == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		U u;
  		while ((v = it.advance()) != null) {
  			if ((u = searchFunction.apply(v)) != null)
  				return u;
  		}
  		return null;
  	}
  
  	/**
  	 * Returns the result of accumulating all values using the given reducer to
  	 * combine values, or null if none.
  	 *
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating all values
  	 */
  	public V reduceValuesSequentially(BiFun<? super V, ? super V, ? extends V> reducer) {
  		if (reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V r = null;
  		V v;
  		while ((v = it.advance()) != null)
  			r = (r == null) ? v : reducer.apply(r, v);
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all values
  	 * using the given reducer to combine values, or null if none.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case it is not
  	 *            combined)
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all values
  	 */
  	public <U> U reduceValuesSequentially(Fun<? super V, ? extends U> transformer,
  			BiFun<? super U, ? super U, ? extends U> reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		U r = null, u;
  		V v;
  		while ((v = it.advance()) != null) {
  			if ((u = transformer.apply(v)) != null)
  				r = (r == null) ? u : reducer.apply(r, u);
  		}
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all values
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all values
  	 */
  	public double reduceValuesToDoubleSequentially(ObjectToDouble<? super V> transformer, double basis,
  			DoubleByDoubleToDouble reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		double r = basis;
  		V v;
  		while ((v = it.advance()) != null)
  			r = reducer.apply(r, transformer.apply(v));
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all values
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all values
  	 */
  	public long reduceValuesToLongSequentially(ObjectToLong<? super V> transformer, long basis,
  			LongByLongToLong reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		long r = basis;
  		V v;
  		while ((v = it.advance()) != null)
  			r = reducer.apply(r, transformer.apply(v));
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all values
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all values
  	 */
  	public int reduceValuesToIntSequentially(ObjectToInt<? super V> transformer, int basis, IntByIntToInt reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		int r = basis;
  		V v;
  		while ((v = it.advance()) != null)
  			r = reducer.apply(r, transformer.apply(v));
  		return r;
  	}
  
  	/**
  	 * Performs the given action for each entry.
  	 *
  	 * @param action
  	 *            the action
  	 */
  	@SuppressWarnings("unchecked")
  	public void forEachEntrySequentially(Action<Map.Entry<K, V>> action) {
  		if (action == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		while ((v = it.advance()) != null)
  			action.apply(entryFor((K) it.nextKey, v));
  	}
  
  	/**
  	 * Performs the given action for each non-null transformation of each entry.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case the action
  	 *            is not applied)
  	 * @param action
  	 *            the action
  	 */
  	@SuppressWarnings("unchecked")
  	public <U> void forEachEntrySequentially(Fun<Map.Entry<K, V>, ? extends U> transformer, Action<U> action) {
  		if (transformer == null || action == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		U u;
  		while ((v = it.advance()) != null) {
  			if ((u = transformer.apply(entryFor((K) it.nextKey, v))) != null)
  				action.apply(u);
  		}
  	}
  
  	/**
  	 * Returns a non-null result from applying the given search function on each
  	 * entry, or null if none.
  	 *
  	 * @param searchFunction
  	 *            a function returning a non-null result on success, else null
  	 * @return a non-null result from applying the given search function on each
  	 *         entry, or null if none
  	 */
  	@SuppressWarnings("unchecked")
  	public <U> U searchEntriesSequentially(Fun<Map.Entry<K, V>, ? extends U> searchFunction) {
  		if (searchFunction == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		V v;
  		U u;
  		while ((v = it.advance()) != null) {
  			if ((u = searchFunction.apply(entryFor((K) it.nextKey, v))) != null)
  				return u;
  		}
  		return null;
  	}
  
  	/**
  	 * Returns the result of accumulating all entries using the given reducer to
  	 * combine values, or null if none.
  	 *
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating all entries
  	 */
  	@SuppressWarnings("unchecked")
  	public Map.Entry<K, V> reduceEntriesSequentially(
  			BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer) {
  		if (reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		Map.Entry<K, V> r = null;
  		V v;
  		while ((v = it.advance()) != null) {
  			Map.Entry<K, V> u = entryFor((K) it.nextKey, v);
  			r = (r == null) ? u : reducer.apply(r, u);
  		}
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all
  	 * entries using the given reducer to combine values, or null if none.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case it is not
  	 *            combined)
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all
  	 *         entries
  	 */
  	@SuppressWarnings("unchecked")
  	public <U> U reduceEntriesSequentially(Fun<Map.Entry<K, V>, ? extends U> transformer,
  			BiFun<? super U, ? super U, ? extends U> reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		U r = null, u;
  		V v;
  		while ((v = it.advance()) != null) {
  			if ((u = transformer.apply(entryFor((K) it.nextKey, v))) != null)
  				r = (r == null) ? u : reducer.apply(r, u);
  		}
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all
  	 * entries using the given reducer to combine values, and the given basis as
  	 * an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all
  	 *         entries
  	 */
  	@SuppressWarnings("unchecked")
  	public double reduceEntriesToDoubleSequentially(ObjectToDouble<Map.Entry<K, V>> transformer, double basis,
  			DoubleByDoubleToDouble reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		double r = basis;
  		V v;
  		while ((v = it.advance()) != null)
  			r = reducer.apply(r, transformer.apply(entryFor((K) it.nextKey, v)));
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all
  	 * entries using the given reducer to combine values, and the given basis as
  	 * an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all
  	 *         entries
  	 */
  	@SuppressWarnings("unchecked")
  	public long reduceEntriesToLongSequentially(ObjectToLong<Map.Entry<K, V>> transformer, long basis,
  			LongByLongToLong reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		long r = basis;
  		V v;
  		while ((v = it.advance()) != null)
  			r = reducer.apply(r, transformer.apply(entryFor((K) it.nextKey, v)));
  		return r;
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all
  	 * entries using the given reducer to combine values, and the given basis as
  	 * an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all
  	 *         entries
  	 */
  	@SuppressWarnings("unchecked")
  	public int reduceEntriesToIntSequentially(ObjectToInt<Map.Entry<K, V>> transformer, int basis,
  			IntByIntToInt reducer) {
  		if (transformer == null || reducer == null)
  			throw new NullPointerException();
  		Traverser<K, V, Object> it = new Traverser<K, V, Object>(this);
  		int r = basis;
  		V v;
  		while ((v = it.advance()) != null)
  			r = reducer.apply(r, transformer.apply(entryFor((K) it.nextKey, v)));
  		return r;
  	}
  
  	// Parallel bulk operations
  	/**
  	 * Performs the given action for each (key, value).
  	 *
  	 * @param action
  	 *            the action
  	 */
  	public void forEachInParallel(BiAction<K, V> action) {
  		ForkJoinTasks.forEach(this, action).invoke();
  	}
  
  	/**
  	 * Performs the given action for each non-null transformation of each (key,
  	 * value).
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case the action
  	 *            is not applied)
  	 * @param action
  	 *            the action
  	 */
  	public <U> void forEachInParallel(BiFun<? super K, ? super V, ? extends U> transformer, Action<U> action) {
  		ForkJoinTasks.forEach(this, transformer, action).invoke();
  	}
  
  	/**
  	 * Returns a non-null result from applying the given search function on each
  	 * (key, value), or null if none. Upon success, further element processing
  	 * is suppressed and the results of any other parallel invocations of the
  	 * search function are ignored.
  	 *
  	 * @param searchFunction
  	 *            a function returning a non-null result on success, else null
  	 * @return a non-null result from applying the given search function on each
  	 *         (key, value), or null if none
  	 */
  	public <U> U searchInParallel(BiFun<? super K, ? super V, ? extends U> searchFunction) {
  		return ForkJoinTasks.search(this, searchFunction).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all (key,
  	 * value) pairs using the given reducer to combine values, or null if none.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case it is not
  	 *            combined)
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all (key,
  	 *         value) pairs
  	 */
  	public <U> U reduceInParallel(BiFun<? super K, ? super V, ? extends U> transformer,
  			BiFun<? super U, ? super U, ? extends U> reducer) {
  		return ForkJoinTasks.reduce(this, transformer, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all (key,
  	 * value) pairs using the given reducer to combine values, and the given
  	 * basis as an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all (key,
  	 *         value) pairs
  	 */
  	public double reduceToDoubleInParallel(ObjectByObjectToDouble<? super K, ? super V> transformer, double basis,
  			DoubleByDoubleToDouble reducer) {
  		return ForkJoinTasks.reduceToDouble(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all (key,
  	 * value) pairs using the given reducer to combine values, and the given
  	 * basis as an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all (key,
  	 *         value) pairs
  	 */
  	public long reduceToLongInParallel(ObjectByObjectToLong<? super K, ? super V> transformer, long basis,
  			LongByLongToLong reducer) {
  		return ForkJoinTasks.reduceToLong(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all (key,
  	 * value) pairs using the given reducer to combine values, and the given
  	 * basis as an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all (key,
  	 *         value) pairs
  	 */
  	public int reduceToIntInParallel(ObjectByObjectToInt<? super K, ? super V> transformer, int basis,
  			IntByIntToInt reducer) {
  		return ForkJoinTasks.reduceToInt(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Performs the given action for each key.
  	 *
  	 * @param action
  	 *            the action
  	 */
  	public void forEachKeyInParallel(Action<K> action) {
  		ForkJoinTasks.forEachKey(this, action).invoke();
  	}
  
  	/**
  	 * Performs the given action for each non-null transformation of each key.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case the action
  	 *            is not applied)
  	 * @param action
  	 *            the action
  	 */
  	public <U> void forEachKeyInParallel(Fun<? super K, ? extends U> transformer, Action<U> action) {
  		ForkJoinTasks.forEachKey(this, transformer, action).invoke();
  	}
  
  	/**
  	 * Returns a non-null result from applying the given search function on each
  	 * key, or null if none. Upon success, further element processing is
  	 * suppressed and the results of any other parallel invocations of the
  	 * search function are ignored.
  	 *
  	 * @param searchFunction
  	 *            a function returning a non-null result on success, else null
  	 * @return a non-null result from applying the given search function on each
  	 *         key, or null if none
  	 */
  	public <U> U searchKeysInParallel(Fun<? super K, ? extends U> searchFunction) {
  		return ForkJoinTasks.searchKeys(this, searchFunction).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating all keys using the given reducer to
  	 * combine values, or null if none.
  	 *
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating all keys using the given reducer to
  	 *         combine values, or null if none
  	 */
  	public K reduceKeysInParallel(BiFun<? super K, ? super K, ? extends K> reducer) {
  		return ForkJoinTasks.reduceKeys(this, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all keys
  	 * using the given reducer to combine values, or null if none.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case it is not
  	 *            combined)
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all keys
  	 */
  	public <U> U reduceKeysInParallel(Fun<? super K, ? extends U> transformer,
  			BiFun<? super U, ? super U, ? extends U> reducer) {
  		return ForkJoinTasks.reduceKeys(this, transformer, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all keys
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all keys
  	 */
  	public double reduceKeysToDoubleInParallel(ObjectToDouble<? super K> transformer, double basis,
  			DoubleByDoubleToDouble reducer) {
  		return ForkJoinTasks.reduceKeysToDouble(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all keys
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all keys
  	 */
  	public long reduceKeysToLongInParallel(ObjectToLong<? super K> transformer, long basis, LongByLongToLong reducer) {
  		return ForkJoinTasks.reduceKeysToLong(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all keys
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all keys
  	 */
  	public int reduceKeysToIntInParallel(ObjectToInt<? super K> transformer, int basis, IntByIntToInt reducer) {
  		return ForkJoinTasks.reduceKeysToInt(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Performs the given action for each value.
  	 *
  	 * @param action
  	 *            the action
  	 */
  	public void forEachValueInParallel(Action<V> action) {
  		ForkJoinTasks.forEachValue(this, action).invoke();
  	}
  
  	/**
  	 * Performs the given action for each non-null transformation of each value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case the action
  	 *            is not applied)
  	 */
  	public <U> void forEachValueInParallel(Fun<? super V, ? extends U> transformer, Action<U> action) {
  		ForkJoinTasks.forEachValue(this, transformer, action).invoke();
  	}
  
  	/**
  	 * Returns a non-null result from applying the given search function on each
  	 * value, or null if none. Upon success, further element processing is
  	 * suppressed and the results of any other parallel invocations of the
  	 * search function are ignored.
  	 *
  	 * @param searchFunction
  	 *            a function returning a non-null result on success, else null
  	 * @return a non-null result from applying the given search function on each
  	 *         value, or null if none
  	 */
  	public <U> U searchValuesInParallel(Fun<? super V, ? extends U> searchFunction) {
  		return ForkJoinTasks.searchValues(this, searchFunction).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating all values using the given reducer to
  	 * combine values, or null if none.
  	 *
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating all values
  	 */
  	public V reduceValuesInParallel(BiFun<? super V, ? super V, ? extends V> reducer) {
  		return ForkJoinTasks.reduceValues(this, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all values
  	 * using the given reducer to combine values, or null if none.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case it is not
  	 *            combined)
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all values
  	 */
  	public <U> U reduceValuesInParallel(Fun<? super V, ? extends U> transformer,
  			BiFun<? super U, ? super U, ? extends U> reducer) {
  		return ForkJoinTasks.reduceValues(this, transformer, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all values
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all values
  	 */
  	public double reduceValuesToDoubleInParallel(ObjectToDouble<? super V> transformer, double basis,
  			DoubleByDoubleToDouble reducer) {
  		return ForkJoinTasks.reduceValuesToDouble(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all values
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all values
  	 */
  	public long reduceValuesToLongInParallel(ObjectToLong<? super V> transformer, long basis,
  			LongByLongToLong reducer) {
  		return ForkJoinTasks.reduceValuesToLong(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all values
  	 * using the given reducer to combine values, and the given basis as an
  	 * identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all values
  	 */
  	public int reduceValuesToIntInParallel(ObjectToInt<? super V> transformer, int basis, IntByIntToInt reducer) {
  		return ForkJoinTasks.reduceValuesToInt(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Performs the given action for each entry.
  	 *
  	 * @param action
  	 *            the action
  	 */
  	public void forEachEntryInParallel(Action<Map.Entry<K, V>> action) {
  		ForkJoinTasks.forEachEntry(this, action).invoke();
  	}
  
  	/**
  	 * Performs the given action for each non-null transformation of each entry.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case the action
  	 *            is not applied)
  	 * @param action
  	 *            the action
  	 */
  	public <U> void forEachEntryInParallel(Fun<Map.Entry<K, V>, ? extends U> transformer, Action<U> action) {
  		ForkJoinTasks.forEachEntry(this, transformer, action).invoke();
  	}
  
  	/**
  	 * Returns a non-null result from applying the given search function on each
  	 * entry, or null if none. Upon success, further element processing is
  	 * suppressed and the results of any other parallel invocations of the
  	 * search function are ignored.
  	 *
  	 * @param searchFunction
  	 *            a function returning a non-null result on success, else null
  	 * @return a non-null result from applying the given search function on each
  	 *         entry, or null if none
  	 */
  	public <U> U searchEntriesInParallel(Fun<Map.Entry<K, V>, ? extends U> searchFunction) {
  		return ForkJoinTasks.searchEntries(this, searchFunction).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating all entries using the given reducer to
  	 * combine values, or null if none.
  	 *
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating all entries
  	 */
  	public Map.Entry<K, V> reduceEntriesInParallel(
  			BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer) {
  		return ForkJoinTasks.reduceEntries(this, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all
  	 * entries using the given reducer to combine values, or null if none.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element, or
  	 *            null if there is no transformation (in which case it is not
  	 *            combined)
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all
  	 *         entries
  	 */
  	public <U> U reduceEntriesInParallel(Fun<Map.Entry<K, V>, ? extends U> transformer,
  			BiFun<? super U, ? super U, ? extends U> reducer) {
  		return ForkJoinTasks.reduceEntries(this, transformer, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all
  	 * entries using the given reducer to combine values, and the given basis as
  	 * an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all
  	 *         entries
  	 */
  	public double reduceEntriesToDoubleInParallel(ObjectToDouble<Map.Entry<K, V>> transformer, double basis,
  			DoubleByDoubleToDouble reducer) {
  		return ForkJoinTasks.reduceEntriesToDouble(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all
  	 * entries using the given reducer to combine values, and the given basis as
  	 * an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all
  	 *         entries
  	 */
  	public long reduceEntriesToLongInParallel(ObjectToLong<Map.Entry<K, V>> transformer, long basis,
  			LongByLongToLong reducer) {
  		return ForkJoinTasks.reduceEntriesToLong(this, transformer, basis, reducer).invoke();
  	}
  
  	/**
  	 * Returns the result of accumulating the given transformation of all
  	 * entries using the given reducer to combine values, and the given basis as
  	 * an identity value.
  	 *
  	 * @param transformer
  	 *            a function returning the transformation for an element
  	 * @param basis
  	 *            the identity (initial default value) for the reduction
  	 * @param reducer
  	 *            a commutative associative combining function
  	 * @return the result of accumulating the given transformation of all
  	 *         entries
  	 */
  	public int reduceEntriesToIntInParallel(ObjectToInt<Map.Entry<K, V>> transformer, int basis,
  			IntByIntToInt reducer) {
  		return ForkJoinTasks.reduceEntriesToInt(this, transformer, basis, reducer).invoke();
  	}
  
  	/* ----------------Views -------------- */
  	/**
  	 * Base class for views.
  	 */
  	abstract static class CHMView<K, V> {
  
  		final ConcurrentHashMapV8<K, V> map;
  
  		CHMView(ConcurrentHashMapV8<K, V> map) {
  			this.map = map;
  		}
  
  		/**
  		 * Returns the map backing this view.
  		 *
  		 * @return the map backing this view
  		 */
  		public ConcurrentHashMapV8<K, V> getMap() {
  			return map;
  		}
  
  		public final int size() {
  			return map.size();
  		}
  
  		public final boolean isEmpty() {
  			return map.isEmpty();
  		}
  
  		public final void clear() {
  			map.clear();
  		}
  
  		// implementations below rely on concrete classes supplying these
  		public abstract Iterator<?> iterator();
  
  		public abstract boolean contains(Object o);
  
  		public abstract boolean remove(Object o);
  
  		private static final String oomeMsg = "Required array size too large";
  
  		public final Object[] toArray() {
  			long sz = map.mappingCount();
  			if (sz > (MAX_ARRAY_SIZE))
  				throw new OutOfMemoryError(oomeMsg);
  			int n = (int) sz;
  			Object[] r = new Object[n];
  			int i = 0;
  			Iterator<?> it = iterator();
  			while (it.hasNext()) {
  				if (i == n) {
  					if (n >= MAX_ARRAY_SIZE)
  						throw new OutOfMemoryError(oomeMsg);
  					if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
  						n = MAX_ARRAY_SIZE;
  					else
  						n += (n >>> 1) + 1;
  					r = Arrays.copyOf(r, n);
  				}
  				r[i++] = it.next();
  			}
  			return (i == n) ? r : Arrays.copyOf(r, i);
  		}
  
  		@SuppressWarnings("unchecked")
  		public final <T> T[] toArray(T[] a) {
  			long sz = map.mappingCount();
  			if (sz > (MAX_ARRAY_SIZE))
  				throw new OutOfMemoryError(oomeMsg);
  			int m = (int) sz;
  			T[] r = (a.length >= m) ? a : (T[]) java.lang.reflect.Array.newInstance(a.getClass().getComponentType(), m);
  			int n = r.length;
  			int i = 0;
  			Iterator<?> it = iterator();
  			while (it.hasNext()) {
  				if (i == n) {
  					if (n >= MAX_ARRAY_SIZE)
  						throw new OutOfMemoryError(oomeMsg);
  					if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1)
  						n = MAX_ARRAY_SIZE;
  					else
  						n += (n >>> 1) + 1;
  					r = Arrays.copyOf(r, n);
  				}
  				r[i++] = (T) it.next();
  			}
  			if (a == r && i < n) {
  				r[i] = null; // null-terminate
  				return r;
  			}
  			return (i == n) ? r : Arrays.copyOf(r, i);
  		}
  
  		@Override
  		public final int hashCode() {
  			int h = 0;
  			for (Iterator<?> it = iterator(); it.hasNext();)
  				h += it.next().hashCode();
  			return h;
  		}
  
  		@Override
  		public final String toString() {
  			StringBuilder sb = new StringBuilder();
  			sb.append('[');
  			Iterator<?> it = iterator();
  			if (it.hasNext()) {
  				for (;;) {
  					Object e = it.next();
  					sb.append(e == this ? "(this Collection)" : e);
  					if (!it.hasNext())
  						break;
  					sb.append(',').append(' ');
  				}
  			}
  			return sb.append(']').toString();
  		}
  
  		public final boolean containsAll(Collection<?> c) {
  			if (c != this) {
  				for (Iterator<?> it = c.iterator(); it.hasNext();) {
  					Object e = it.next();
  					if (e == null || !contains(e))
  						return false;
  				}
  			}
  			return true;
  		}
  
  		public final boolean removeAll(Collection<?> c) {
  			boolean modified = false;
  			for (Iterator<?> it = iterator(); it.hasNext();) {
  				if (c.contains(it.next())) {
  					it.remove();
  					modified = true;
  				}
  			}
  			return modified;
  		}
  
  		public final boolean retainAll(Collection<?> c) {
  			boolean modified = false;
  			for (Iterator<?> it = iterator(); it.hasNext();) {
  				if (!c.contains(it.next())) {
  					it.remove();
  					modified = true;
  				}
  			}
  			return modified;
  		}
  	}
  
  	/**
  	 * A view of a ConcurrentHashMapV8 as a {@link Set} of keys, in which
  	 * additions may optionally be enabled by mapping to a common value. This
  	 * class cannot be directly instantiated. See {@link #keySet()},
  	 * {@link #keySet(Object)}, {@link #newKeySet()}, {@link #newKeySet(int)}.
  	 */
  	public static class KeySetView<K, V> extends CHMView<K, V> implements Set<K>, java.io.Serializable {
  
  		private static final long serialVersionUID = 7249069246763182397L;
  		private final V value;
  
  		KeySetView(ConcurrentHashMapV8<K, V> map, V value) { // non-public
  			super(map);
  			this.value = value;
  		}
  
  		/**
  		 * Returns the default mapped value for additions, or {@code null} if
  		 * additions are not supported.
  		 *
  		 * @return the default mapped value for additions, or {@code null} if
  		 *         not supported
  		 */
  		public V getMappedValue() {
  			return value;
  		}
  
  		// implement Set API
  		@Override
  		public boolean contains(Object o) {
  			return map.containsKey(o);
  		}
  
  		@Override
  		public boolean remove(Object o) {
  			return map.remove(o) != null;
  		}
  
  		/**
  		 * Returns a "weakly consistent" iterator that will never throw
  		 * {@link ConcurrentModificationException}, and guarantees to traverse
  		 * elements as they existed upon construction of the iterator, and may
  		 * (but is not guaranteed to) reflect any modifications subsequent to
  		 * construction.
  		 *
  		 * @return an iterator over the keys of this map
  		 */
  		@Override
  		public Iterator<K> iterator() {
  			return new KeyIterator<K, V>(map);
  		}
  
  		@Override
  		public boolean add(K e) {
  			V v;
  			if ((v = value) == null)
  				throw new UnsupportedOperationException();
  			return map.internalPut(e, v, true) == null;
  		}
  
  		@Override
  		public boolean addAll(Collection<? extends K> c) {
  			boolean added = false;
  			V v;
  			if ((v = value) == null)
  				throw new UnsupportedOperationException();
  			for (K e : c) {
  				if (map.internalPut(e, v, true) == null)
  					added = true;
  			}
  			return added;
  		}
  
  		@Override
  		public boolean equals(Object o) {
  			Set<?> c;
  			return ((o instanceof Set) && ((c = (Set<?>) o) == this || (containsAll(c) && c.containsAll(this))));
  		}
  	}
  
  	/**
  	 * A view of a ConcurrentHashMapV8 as a {@link Collection} of values, in
  	 * which additions are disabled. This class cannot be directly instantiated.
  	 * See {@link #values()}.
  	 *
  	 * <p>
  	 * The view's {@code iterator} is a "weakly consistent" iterator that will
  	 * never throw {@link ConcurrentModificationException}, and guarantees to
  	 * traverse elements as they existed upon construction of the iterator, and
  	 * may (but is not guaranteed to) reflect any modifications subsequent to
  	 * construction.
  	 */
  	public static final class ValuesView<K, V> extends CHMView<K, V> implements Collection<V> {
  
  		ValuesView(ConcurrentHashMapV8<K, V> map) {
  			super(map);
  		}
  
  		@Override
  		public final boolean contains(Object o) {
  			return map.containsValue(o);
  		}
  
  		@Override
  		public final boolean remove(Object o) {
  			if (o != null) {
  				Iterator<V> it = new ValueIterator<K, V>(map);
  				while (it.hasNext()) {
  					if (o.equals(it.next())) {
  						it.remove();
  						return true;
  					}
  				}
  			}
  			return false;
  		}
  
  		/**
  		 * Returns a "weakly consistent" iterator that will never throw
  		 * {@link ConcurrentModificationException}, and guarantees to traverse
  		 * elements as they existed upon construction of the iterator, and may
  		 * (but is not guaranteed to) reflect any modifications subsequent to
  		 * construction.
  		 *
  		 * @return an iterator over the values of this map
  		 */
  		@Override
  		public final Iterator<V> iterator() {
  			return new ValueIterator<K, V>(map);
  		}
  
  		@Override
  		public final boolean add(V e) {
  			throw new UnsupportedOperationException();
  		}
  
  		@Override
  		public final boolean addAll(Collection<? extends V> c) {
  			throw new UnsupportedOperationException();
  		}
  	}
  
  	/**
  	 * A view of a ConcurrentHashMapV8 as a {@link Set} of (key, value) entries.
  	 * This class cannot be directly instantiated. See {@link #entrySet()}.
  	 */
  	public static final class EntrySetView<K, V> extends CHMView<K, V> implements Set<Map.Entry<K, V>> {
  
  		EntrySetView(ConcurrentHashMapV8<K, V> map) {
  			super(map);
  		}
  
  		@Override
  		public final boolean contains(Object o) {
  			Object k, v, r;
  			Map.Entry<?, ?> e;
  			return ((o instanceof Map.Entry) && (k = (e = (Map.Entry<?, ?>) o).getKey()) != null
  					&& (r = map.get(k)) != null && (v = e.getValue()) != null && (v == r || v.equals(r)));
  		}
  
  		@Override
  		public final boolean remove(Object o) {
  			Object k, v;
  			Map.Entry<?, ?> e;
  			return ((o instanceof Map.Entry) && (k = (e = (Map.Entry<?, ?>) o).getKey()) != null
  					&& (v = e.getValue()) != null && map.remove(k, v));
  		}
  
  		/**
  		 * Returns a "weakly consistent" iterator that will never throw
  		 * {@link ConcurrentModificationException}, and guarantees to traverse
  		 * elements as they existed upon construction of the iterator, and may
  		 * (but is not guaranteed to) reflect any modifications subsequent to
  		 * construction.
  		 *
  		 * @return an iterator over the entries of this map
  		 */
  		@Override
  		public final Iterator<Map.Entry<K, V>> iterator() {
  			return new EntryIterator<K, V>(map);
  		}
  
  		@Override
  		public final boolean add(Entry<K, V> e) {
  			return map.internalPut(e.getKey(), e.getValue(), false) == null;
  		}
  
  		@Override
  		public final boolean addAll(Collection<? extends Entry<K, V>> c) {
  			boolean added = false;
  			for (Entry<K, V> e : c) {
  				if (add(e))
  					added = true;
  			}
  			return added;
  		}
  
  		@Override
  		public boolean equals(Object o) {
  			Set<?> c;
  			return ((o instanceof Set) && ((c = (Set<?>) o) == this || (containsAll(c) && c.containsAll(this))));
  		}
  	}
  
  	// ---------------------------------------------------------------------
  	/**
  	 * Predefined tasks for performing bulk parallel operations on
  	 * ConcurrentHashMapV8s. These tasks follow the forms and rules used for
  	 * bulk operations. Each method has the same name, but returns a task rather
  	 * than invoking it. These methods may be useful in custom applications such
  	 * as submitting a task without waiting for completion, using a custom pool,
  	 * or combining with other tasks.
  	 */
  	public static class ForkJoinTasks {
  
  		private ForkJoinTasks() {
  		}
  
  		/**
  		 * Returns a task that when invoked, performs the given action for each
  		 * (key, value)
  		 *
  		 * @param map
  		 *            the map
  		 * @param action
  		 *            the action
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Void> forEach(ConcurrentHashMapV8<K, V> map, BiAction<K, V> action) {
  			if (action == null)
  				throw new NullPointerException();
  			return new ForEachMappingTask<K, V>(map, null, -1, action);
  		}
  
  		/**
  		 * Returns a task that when invoked, performs the given action for each
  		 * non-null transformation of each (key, value)
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element, or
  		 *            null if there is no transformation (in which case the
  		 *            action is not applied)
  		 * @param action
  		 *            the action
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<Void> forEach(ConcurrentHashMapV8<K, V> map,
  				BiFun<? super K, ? super V, ? extends U> transformer, Action<U> action) {
  			if (transformer == null || action == null)
  				throw new NullPointerException();
  			return new ForEachTransformedMappingTask<K, V, U>(map, null, -1, transformer, action);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns a non-null result from
  		 * applying the given search function on each (key, value), or null if
  		 * none. Upon success, further element processing is suppressed and the
  		 * results of any other parallel invocations of the search function are
  		 * ignored.
  		 *
  		 * @param map
  		 *            the map
  		 * @param searchFunction
  		 *            a function returning a non-null result on success, else
  		 *            null
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<U> search(ConcurrentHashMapV8<K, V> map,
  				BiFun<? super K, ? super V, ? extends U> searchFunction) {
  			if (searchFunction == null)
  				throw new NullPointerException();
  			return new SearchMappingsTask<K, V, U>(map, null, -1, searchFunction, new AtomicReference<U>());
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all (key, value) pairs using the given
  		 * reducer to combine values, or null if none.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element, or
  		 *            null if there is no transformation (in which case it is
  		 *            not combined)
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<U> reduce(ConcurrentHashMapV8<K, V> map,
  				BiFun<? super K, ? super V, ? extends U> transformer,
  				BiFun<? super U, ? super U, ? extends U> reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceMappingsTask<K, V, U>(map, null, -1, null, transformer, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all (key, value) pairs using the given
  		 * reducer to combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Double> reduceToDouble(ConcurrentHashMapV8<K, V> map,
  				ObjectByObjectToDouble<? super K, ? super V> transformer, double basis,
  				DoubleByDoubleToDouble reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceMappingsToDoubleTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all (key, value) pairs using the given
  		 * reducer to combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Long> reduceToLong(ConcurrentHashMapV8<K, V> map,
  				ObjectByObjectToLong<? super K, ? super V> transformer, long basis, LongByLongToLong reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceMappingsToLongTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all (key, value) pairs using the given
  		 * reducer to combine values, and the given basis as an identity value.
  		 *
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Integer> reduceToInt(ConcurrentHashMapV8<K, V> map,
  				ObjectByObjectToInt<? super K, ? super V> transformer, int basis, IntByIntToInt reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceMappingsToIntTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, performs the given action for each
  		 * key.
  		 *
  		 * @param map
  		 *            the map
  		 * @param action
  		 *            the action
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Void> forEachKey(ConcurrentHashMapV8<K, V> map, Action<K> action) {
  			if (action == null)
  				throw new NullPointerException();
  			return new ForEachKeyTask<K, V>(map, null, -1, action);
  		}
  
  		/**
  		 * Returns a task that when invoked, performs the given action for each
  		 * non-null transformation of each key.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element, or
  		 *            null if there is no transformation (in which case the
  		 *            action is not applied)
  		 * @param action
  		 *            the action
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<Void> forEachKey(ConcurrentHashMapV8<K, V> map,
  				Fun<? super K, ? extends U> transformer, Action<U> action) {
  			if (transformer == null || action == null)
  				throw new NullPointerException();
  			return new ForEachTransformedKeyTask<K, V, U>(map, null, -1, transformer, action);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns a non-null result from
  		 * applying the given search function on each key, or null if none. Upon
  		 * success, further element processing is suppressed and the results of
  		 * any other parallel invocations of the search function are ignored.
  		 *
  		 * @param map
  		 *            the map
  		 * @param searchFunction
  		 *            a function returning a non-null result on success, else
  		 *            null
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<U> searchKeys(ConcurrentHashMapV8<K, V> map,
  				Fun<? super K, ? extends U> searchFunction) {
  			if (searchFunction == null)
  				throw new NullPointerException();
  			return new SearchKeysTask<K, V, U>(map, null, -1, searchFunction, new AtomicReference<U>());
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * all keys using the given reducer to combine values, or null if none.
  		 *
  		 * @param map
  		 *            the map
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<K> reduceKeys(ConcurrentHashMapV8<K, V> map,
  				BiFun<? super K, ? super K, ? extends K> reducer) {
  			if (reducer == null)
  				throw new NullPointerException();
  			return new ReduceKeysTask<K, V>(map, null, -1, null, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all keys using the given reducer to
  		 * combine values, or null if none.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element, or
  		 *            null if there is no transformation (in which case it is
  		 *            not combined)
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<U> reduceKeys(ConcurrentHashMapV8<K, V> map,
  				Fun<? super K, ? extends U> transformer, BiFun<? super U, ? super U, ? extends U> reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceKeysTask<K, V, U>(map, null, -1, null, transformer, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all keys using the given reducer to
  		 * combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Double> reduceKeysToDouble(ConcurrentHashMapV8<K, V> map,
  				ObjectToDouble<? super K> transformer, double basis, DoubleByDoubleToDouble reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceKeysToDoubleTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all keys using the given reducer to
  		 * combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Long> reduceKeysToLong(ConcurrentHashMapV8<K, V> map,
  				ObjectToLong<? super K> transformer, long basis, LongByLongToLong reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceKeysToLongTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all keys using the given reducer to
  		 * combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Integer> reduceKeysToInt(ConcurrentHashMapV8<K, V> map,
  				ObjectToInt<? super K> transformer, int basis, IntByIntToInt reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceKeysToIntTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, performs the given action for each
  		 * value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param action
  		 *            the action
  		 */
  		public static <K, V> ForkJoinTask<Void> forEachValue(ConcurrentHashMapV8<K, V> map, Action<V> action) {
  			if (action == null)
  				throw new NullPointerException();
  			return new ForEachValueTask<K, V>(map, null, -1, action);
  		}
  
  		/**
  		 * Returns a task that when invoked, performs the given action for each
  		 * non-null transformation of each value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element, or
  		 *            null if there is no transformation (in which case the
  		 *            action is not applied)
  		 * @param action
  		 *            the action
  		 */
  		public static <K, V, U> ForkJoinTask<Void> forEachValue(ConcurrentHashMapV8<K, V> map,
  				Fun<? super V, ? extends U> transformer, Action<U> action) {
  			if (transformer == null || action == null)
  				throw new NullPointerException();
  			return new ForEachTransformedValueTask<K, V, U>(map, null, -1, transformer, action);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns a non-null result from
  		 * applying the given search function on each value, or null if none.
  		 * Upon success, further element processing is suppressed and the
  		 * results of any other parallel invocations of the search function are
  		 * ignored.
  		 *
  		 * @param map
  		 *            the map
  		 * @param searchFunction
  		 *            a function returning a non-null result on success, else
  		 *            null
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<U> searchValues(ConcurrentHashMapV8<K, V> map,
  				Fun<? super V, ? extends U> searchFunction) {
  			if (searchFunction == null)
  				throw new NullPointerException();
  			return new SearchValuesTask<K, V, U>(map, null, -1, searchFunction, new AtomicReference<U>());
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * all values using the given reducer to combine values, or null if
  		 * none.
  		 *
  		 * @param map
  		 *            the map
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<V> reduceValues(ConcurrentHashMapV8<K, V> map,
  				BiFun<? super V, ? super V, ? extends V> reducer) {
  			if (reducer == null)
  				throw new NullPointerException();
  			return new ReduceValuesTask<K, V>(map, null, -1, null, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all values using the given reducer to
  		 * combine values, or null if none.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element, or
  		 *            null if there is no transformation (in which case it is
  		 *            not combined)
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<U> reduceValues(ConcurrentHashMapV8<K, V> map,
  				Fun<? super V, ? extends U> transformer, BiFun<? super U, ? super U, ? extends U> reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceValuesTask<K, V, U>(map, null, -1, null, transformer, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all values using the given reducer to
  		 * combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Double> reduceValuesToDouble(ConcurrentHashMapV8<K, V> map,
  				ObjectToDouble<? super V> transformer, double basis, DoubleByDoubleToDouble reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceValuesToDoubleTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all values using the given reducer to
  		 * combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Long> reduceValuesToLong(ConcurrentHashMapV8<K, V> map,
  				ObjectToLong<? super V> transformer, long basis, LongByLongToLong reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceValuesToLongTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all values using the given reducer to
  		 * combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Integer> reduceValuesToInt(ConcurrentHashMapV8<K, V> map,
  				ObjectToInt<? super V> transformer, int basis, IntByIntToInt reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceValuesToIntTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, perform the given action for each
  		 * entry.
  		 *
  		 * @param map
  		 *            the map
  		 * @param action
  		 *            the action
  		 */
  		public static <K, V> ForkJoinTask<Void> forEachEntry(ConcurrentHashMapV8<K, V> map,
  				Action<Map.Entry<K, V>> action) {
  			if (action == null)
  				throw new NullPointerException();
  			return new ForEachEntryTask<K, V>(map, null, -1, action);
  		}
  
  		/**
  		 * Returns a task that when invoked, perform the given action for each
  		 * non-null transformation of each entry.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element, or
  		 *            null if there is no transformation (in which case the
  		 *            action is not applied)
  		 * @param action
  		 *            the action
  		 */
  		public static <K, V, U> ForkJoinTask<Void> forEachEntry(ConcurrentHashMapV8<K, V> map,
  				Fun<Map.Entry<K, V>, ? extends U> transformer, Action<U> action) {
  			if (transformer == null || action == null)
  				throw new NullPointerException();
  			return new ForEachTransformedEntryTask<K, V, U>(map, null, -1, transformer, action);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns a non-null result from
  		 * applying the given search function on each entry, or null if none.
  		 * Upon success, further element processing is suppressed and the
  		 * results of any other parallel invocations of the search function are
  		 * ignored.
  		 *
  		 * @param map
  		 *            the map
  		 * @param searchFunction
  		 *            a function returning a non-null result on success, else
  		 *            null
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<U> searchEntries(ConcurrentHashMapV8<K, V> map,
  				Fun<Map.Entry<K, V>, ? extends U> searchFunction) {
  			if (searchFunction == null)
  				throw new NullPointerException();
  			return new SearchEntriesTask<K, V, U>(map, null, -1, searchFunction, new AtomicReference<U>());
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * all entries using the given reducer to combine values, or null if
  		 * none.
  		 *
  		 * @param map
  		 *            the map
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Map.Entry<K, V>> reduceEntries(ConcurrentHashMapV8<K, V> map,
  				BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer) {
  			if (reducer == null)
  				throw new NullPointerException();
  			return new ReduceEntriesTask<K, V>(map, null, -1, null, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all entries using the given reducer to
  		 * combine values, or null if none.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element, or
  		 *            null if there is no transformation (in which case it is
  		 *            not combined)
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V, U> ForkJoinTask<U> reduceEntries(ConcurrentHashMapV8<K, V> map,
  				Fun<Map.Entry<K, V>, ? extends U> transformer, BiFun<? super U, ? super U, ? extends U> reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceEntriesTask<K, V, U>(map, null, -1, null, transformer, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all entries using the given reducer to
  		 * combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Double> reduceEntriesToDouble(ConcurrentHashMapV8<K, V> map,
  				ObjectToDouble<Map.Entry<K, V>> transformer, double basis, DoubleByDoubleToDouble reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceEntriesToDoubleTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all entries using the given reducer to
  		 * combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Long> reduceEntriesToLong(ConcurrentHashMapV8<K, V> map,
  				ObjectToLong<Map.Entry<K, V>> transformer, long basis, LongByLongToLong reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceEntriesToLongTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  
  		/**
  		 * Returns a task that when invoked, returns the result of accumulating
  		 * the given transformation of all entries using the given reducer to
  		 * combine values, and the given basis as an identity value.
  		 *
  		 * @param map
  		 *            the map
  		 * @param transformer
  		 *            a function returning the transformation for an element
  		 * @param basis
  		 *            the identity (initial default value) for the reduction
  		 * @param reducer
  		 *            a commutative associative combining function
  		 * @return the task
  		 */
  		public static <K, V> ForkJoinTask<Integer> reduceEntriesToInt(ConcurrentHashMapV8<K, V> map,
  				ObjectToInt<Map.Entry<K, V>> transformer, int basis, IntByIntToInt reducer) {
  			if (transformer == null || reducer == null)
  				throw new NullPointerException();
  			return new MapReduceEntriesToIntTask<K, V>(map, null, -1, null, transformer, basis, reducer);
  		}
  	}
  
  	// -------------------------------------------------------
  
  	/*
  	 * Task classes. Coded in a regular but ugly format/style to simplify checks
  	 * that each variant differs in the right way from others. The null
  	 * screenings exist because compilers cannot tell that we've already
  	 * null-checked task arguments, so we force simplest hoisted bypass to help
  	 * avoid convoluted traps.
  	 */
  	@SuppressWarnings("serial")
  	static final class ForEachKeyTask<K, V> extends Traverser<K, V, Void> {
  
  		final Action<K> action;
  
  		ForEachKeyTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b, Action<K> action) {
  			super(m, p, b);
  			this.action = action;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final Action<K> action;
  			if ((action = this.action) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					new ForEachKeyTask<K, V>(map, this, b, action).fork();
  				while (advance() != null)
  					action.apply((K) nextKey);
  				propagateCompletion();
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ForEachValueTask<K, V> extends Traverser<K, V, Void> {
  
  		final Action<V> action;
  
  		ForEachValueTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b, Action<V> action) {
  			super(m, p, b);
  			this.action = action;
  		}
  
  		@Override
  		public final void compute() {
  			final Action<V> action;
  			if ((action = this.action) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					new ForEachValueTask<K, V>(map, this, b, action).fork();
  				V v;
  				while ((v = advance()) != null)
  					action.apply(v);
  				propagateCompletion();
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ForEachEntryTask<K, V> extends Traverser<K, V, Void> {
  
  		final Action<Entry<K, V>> action;
  
  		ForEachEntryTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b, Action<Entry<K, V>> action) {
  			super(m, p, b);
  			this.action = action;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final Action<Entry<K, V>> action;
  			if ((action = this.action) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					new ForEachEntryTask<K, V>(map, this, b, action).fork();
  				V v;
  				while ((v = advance()) != null)
  					action.apply(entryFor((K) nextKey, v));
  				propagateCompletion();
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ForEachMappingTask<K, V> extends Traverser<K, V, Void> {
  
  		final BiAction<K, V> action;
  
  		ForEachMappingTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b, BiAction<K, V> action) {
  			super(m, p, b);
  			this.action = action;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final BiAction<K, V> action;
  			if ((action = this.action) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					new ForEachMappingTask<K, V>(map, this, b, action).fork();
  				V v;
  				while ((v = advance()) != null)
  					action.apply((K) nextKey, v);
  				propagateCompletion();
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ForEachTransformedKeyTask<K, V, U> extends Traverser<K, V, Void> {
  
  		final Fun<? super K, ? extends U> transformer;
  		final Action<U> action;
  
  		ForEachTransformedKeyTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				Fun<? super K, ? extends U> transformer, Action<U> action) {
  			super(m, p, b);
  			this.transformer = transformer;
  			this.action = action;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final Fun<? super K, ? extends U> transformer;
  			final Action<U> action;
  			if ((transformer = this.transformer) != null && (action = this.action) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					new ForEachTransformedKeyTask<K, V, U>(map, this, b, transformer, action).fork();
  				U u;
  				while (advance() != null) {
  					if ((u = transformer.apply((K) nextKey)) != null)
  						action.apply(u);
  				}
  				propagateCompletion();
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ForEachTransformedValueTask<K, V, U> extends Traverser<K, V, Void> {
  
  		final Fun<? super V, ? extends U> transformer;
  		final Action<U> action;
  
  		ForEachTransformedValueTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				Fun<? super V, ? extends U> transformer, Action<U> action) {
  			super(m, p, b);
  			this.transformer = transformer;
  			this.action = action;
  		}
  
  		@Override
  		public final void compute() {
  			final Fun<? super V, ? extends U> transformer;
  			final Action<U> action;
  			if ((transformer = this.transformer) != null && (action = this.action) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					new ForEachTransformedValueTask<K, V, U>(map, this, b, transformer, action).fork();
  				V v;
  				U u;
  				while ((v = advance()) != null) {
  					if ((u = transformer.apply(v)) != null)
  						action.apply(u);
  				}
  				propagateCompletion();
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ForEachTransformedEntryTask<K, V, U> extends Traverser<K, V, Void> {
  
  		final Fun<Map.Entry<K, V>, ? extends U> transformer;
  		final Action<U> action;
  
  		ForEachTransformedEntryTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				Fun<Map.Entry<K, V>, ? extends U> transformer, Action<U> action) {
  			super(m, p, b);
  			this.transformer = transformer;
  			this.action = action;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final Fun<Map.Entry<K, V>, ? extends U> transformer;
  			final Action<U> action;
  			if ((transformer = this.transformer) != null && (action = this.action) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					new ForEachTransformedEntryTask<K, V, U>(map, this, b, transformer, action).fork();
  				V v;
  				U u;
  				while ((v = advance()) != null) {
  					if ((u = transformer.apply(entryFor((K) nextKey, v))) != null)
  						action.apply(u);
  				}
  				propagateCompletion();
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ForEachTransformedMappingTask<K, V, U> extends Traverser<K, V, Void> {
  
  		final BiFun<? super K, ? super V, ? extends U> transformer;
  		final Action<U> action;
  
  		ForEachTransformedMappingTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				BiFun<? super K, ? super V, ? extends U> transformer, Action<U> action) {
  			super(m, p, b);
  			this.transformer = transformer;
  			this.action = action;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final BiFun<? super K, ? super V, ? extends U> transformer;
  			final Action<U> action;
  			if ((transformer = this.transformer) != null && (action = this.action) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					new ForEachTransformedMappingTask<K, V, U>(map, this, b, transformer, action).fork();
  				V v;
  				U u;
  				while ((v = advance()) != null) {
  					if ((u = transformer.apply((K) nextKey, v)) != null)
  						action.apply(u);
  				}
  				propagateCompletion();
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class SearchKeysTask<K, V, U> extends Traverser<K, V, U> {
  
  		final Fun<? super K, ? extends U> searchFunction;
  		final AtomicReference<U> result;
  
  		SearchKeysTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				Fun<? super K, ? extends U> searchFunction, AtomicReference<U> result) {
  			super(m, p, b);
  			this.searchFunction = searchFunction;
  			this.result = result;
  		}
  
  		@Override
  		public final U getRawResult() {
  			return result.get();
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final Fun<? super K, ? extends U> searchFunction;
  			final AtomicReference<U> result;
  			if ((searchFunction = this.searchFunction) != null && (result = this.result) != null) {
  				for (int b;;) {
  					if (result.get() != null)
  						return;
  					if ((b = preSplit()) <= 0)
  						break;
  					new SearchKeysTask<K, V, U>(map, this, b, searchFunction, result).fork();
  				}
  				while (result.get() == null) {
  					U u;
  					if (advance() == null) {
  						propagateCompletion();
  						break;
  					}
  					if ((u = searchFunction.apply((K) nextKey)) != null) {
  						if (result.compareAndSet(null, u))
  							quietlyCompleteRoot();
  						break;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class SearchValuesTask<K, V, U> extends Traverser<K, V, U> {
  
  		final Fun<? super V, ? extends U> searchFunction;
  		final AtomicReference<U> result;
  
  		SearchValuesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				Fun<? super V, ? extends U> searchFunction, AtomicReference<U> result) {
  			super(m, p, b);
  			this.searchFunction = searchFunction;
  			this.result = result;
  		}
  
  		@Override
  		public final U getRawResult() {
  			return result.get();
  		}
  
  		@Override
  		public final void compute() {
  			final Fun<? super V, ? extends U> searchFunction;
  			final AtomicReference<U> result;
  			if ((searchFunction = this.searchFunction) != null && (result = this.result) != null) {
  				for (int b;;) {
  					if (result.get() != null)
  						return;
  					if ((b = preSplit()) <= 0)
  						break;
  					new SearchValuesTask<K, V, U>(map, this, b, searchFunction, result).fork();
  				}
  				while (result.get() == null) {
  					V v;
  					U u;
  					if ((v = advance()) == null) {
  						propagateCompletion();
  						break;
  					}
  					if ((u = searchFunction.apply(v)) != null) {
  						if (result.compareAndSet(null, u))
  							quietlyCompleteRoot();
  						break;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class SearchEntriesTask<K, V, U> extends Traverser<K, V, U> {
  
  		final Fun<Entry<K, V>, ? extends U> searchFunction;
  		final AtomicReference<U> result;
  
  		SearchEntriesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				Fun<Entry<K, V>, ? extends U> searchFunction, AtomicReference<U> result) {
  			super(m, p, b);
  			this.searchFunction = searchFunction;
  			this.result = result;
  		}
  
  		@Override
  		public final U getRawResult() {
  			return result.get();
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final Fun<Entry<K, V>, ? extends U> searchFunction;
  			final AtomicReference<U> result;
  			if ((searchFunction = this.searchFunction) != null && (result = this.result) != null) {
  				for (int b;;) {
  					if (result.get() != null)
  						return;
  					if ((b = preSplit()) <= 0)
  						break;
  					new SearchEntriesTask<K, V, U>(map, this, b, searchFunction, result).fork();
  				}
  				while (result.get() == null) {
  					V v;
  					U u;
  					if ((v = advance()) == null) {
  						propagateCompletion();
  						break;
  					}
  					if ((u = searchFunction.apply(entryFor((K) nextKey, v))) != null) {
  						if (result.compareAndSet(null, u))
  							quietlyCompleteRoot();
  						return;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class SearchMappingsTask<K, V, U> extends Traverser<K, V, U> {
  
  		final BiFun<? super K, ? super V, ? extends U> searchFunction;
  		final AtomicReference<U> result;
  
  		SearchMappingsTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				BiFun<? super K, ? super V, ? extends U> searchFunction, AtomicReference<U> result) {
  			super(m, p, b);
  			this.searchFunction = searchFunction;
  			this.result = result;
  		}
  
  		@Override
  		public final U getRawResult() {
  			return result.get();
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final BiFun<? super K, ? super V, ? extends U> searchFunction;
  			final AtomicReference<U> result;
  			if ((searchFunction = this.searchFunction) != null && (result = this.result) != null) {
  				for (int b;;) {
  					if (result.get() != null)
  						return;
  					if ((b = preSplit()) <= 0)
  						break;
  					new SearchMappingsTask<K, V, U>(map, this, b, searchFunction, result).fork();
  				}
  				while (result.get() == null) {
  					V v;
  					U u;
  					if ((v = advance()) == null) {
  						propagateCompletion();
  						break;
  					}
  					if ((u = searchFunction.apply((K) nextKey, v)) != null) {
  						if (result.compareAndSet(null, u))
  							quietlyCompleteRoot();
  						break;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ReduceKeysTask<K, V> extends Traverser<K, V, K> {
  
  		final BiFun<? super K, ? super K, ? extends K> reducer;
  		K result;
  		ReduceKeysTask<K, V> rights, nextRight;
  
  		ReduceKeysTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b, ReduceKeysTask<K, V> nextRight,
  				BiFun<? super K, ? super K, ? extends K> reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final K getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final BiFun<? super K, ? super K, ? extends K> reducer;
  			if ((reducer = this.reducer) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new ReduceKeysTask<K, V>(map, this, b, rights, reducer)).fork();
  				K r = null;
  				while (advance() != null) {
  					K u = (K) nextKey;
  					r = (r == null) ? u : reducer.apply(r, u);
  				}
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					ReduceKeysTask<K, V> t = (ReduceKeysTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						K tr, sr;
  						if ((sr = s.result) != null)
  							t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr));
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ReduceValuesTask<K, V> extends Traverser<K, V, V> {
  
  		final BiFun<? super V, ? super V, ? extends V> reducer;
  		V result;
  		ReduceValuesTask<K, V> rights, nextRight;
  
  		ReduceValuesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b, ReduceValuesTask<K, V> nextRight,
  				BiFun<? super V, ? super V, ? extends V> reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final V getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final BiFun<? super V, ? super V, ? extends V> reducer;
  			if ((reducer = this.reducer) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new ReduceValuesTask<K, V>(map, this, b, rights, reducer)).fork();
  				V r = null;
  				V v;
  				while ((v = advance()) != null) {
  					V u = v;
  					r = (r == null) ? u : reducer.apply(r, u);
  				}
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					ReduceValuesTask<K, V> t = (ReduceValuesTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						V tr, sr;
  						if ((sr = s.result) != null)
  							t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr));
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class ReduceEntriesTask<K, V> extends Traverser<K, V, Map.Entry<K, V>> {
  
  		final BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer;
  		Map.Entry<K, V> result;
  		ReduceEntriesTask<K, V> rights, nextRight;
  
  		ReduceEntriesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b, ReduceEntriesTask<K, V> nextRight,
  				BiFun<Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Map.Entry<K, V> getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final BiFun<Map.Entry<K, V>, Map.Entry<K, V>, ? extends Map.Entry<K, V>> reducer;
  			if ((reducer = this.reducer) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new ReduceEntriesTask<K, V>(map, this, b, rights, reducer)).fork();
  				Map.Entry<K, V> r = null;
  				V v;
  				while ((v = advance()) != null) {
  					Map.Entry<K, V> u = entryFor((K) nextKey, v);
  					r = (r == null) ? u : reducer.apply(r, u);
  				}
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					ReduceEntriesTask<K, V> t = (ReduceEntriesTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						Map.Entry<K, V> tr, sr;
  						if ((sr = s.result) != null)
  							t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr));
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceKeysTask<K, V, U> extends Traverser<K, V, U> {
  
  		final Fun<? super K, ? extends U> transformer;
  		final BiFun<? super U, ? super U, ? extends U> reducer;
  		U result;
  		MapReduceKeysTask<K, V, U> rights, nextRight;
  
  		MapReduceKeysTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceKeysTask<K, V, U> nextRight, Fun<? super K, ? extends U> transformer,
  				BiFun<? super U, ? super U, ? extends U> reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final U getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final Fun<? super K, ? extends U> transformer;
  			final BiFun<? super U, ? super U, ? extends U> reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceKeysTask<K, V, U>(map, this, b, rights, transformer, reducer)).fork();
  				U r = null, u;
  				while (advance() != null) {
  					if ((u = transformer.apply((K) nextKey)) != null)
  						r = (r == null) ? u : reducer.apply(r, u);
  				}
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceKeysTask<K, V, U> t = (MapReduceKeysTask<K, V, U>) c, s = t.rights;
  					while (s != null) {
  						U tr, sr;
  						if ((sr = s.result) != null)
  							t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr));
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceValuesTask<K, V, U> extends Traverser<K, V, U> {
  
  		final Fun<? super V, ? extends U> transformer;
  		final BiFun<? super U, ? super U, ? extends U> reducer;
  		U result;
  		MapReduceValuesTask<K, V, U> rights, nextRight;
  
  		MapReduceValuesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceValuesTask<K, V, U> nextRight, Fun<? super V, ? extends U> transformer,
  				BiFun<? super U, ? super U, ? extends U> reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final U getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final Fun<? super V, ? extends U> transformer;
  			final BiFun<? super U, ? super U, ? extends U> reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceValuesTask<K, V, U>(map, this, b, rights, transformer, reducer)).fork();
  				U r = null, u;
  				V v;
  				while ((v = advance()) != null) {
  					if ((u = transformer.apply(v)) != null)
  						r = (r == null) ? u : reducer.apply(r, u);
  				}
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceValuesTask<K, V, U> t = (MapReduceValuesTask<K, V, U>) c, s = t.rights;
  					while (s != null) {
  						U tr, sr;
  						if ((sr = s.result) != null)
  							t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr));
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceEntriesTask<K, V, U> extends Traverser<K, V, U> {
  
  		final Fun<Map.Entry<K, V>, ? extends U> transformer;
  		final BiFun<? super U, ? super U, ? extends U> reducer;
  		U result;
  		MapReduceEntriesTask<K, V, U> rights, nextRight;
  
  		MapReduceEntriesTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceEntriesTask<K, V, U> nextRight, Fun<Map.Entry<K, V>, ? extends U> transformer,
  				BiFun<? super U, ? super U, ? extends U> reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final U getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final Fun<Map.Entry<K, V>, ? extends U> transformer;
  			final BiFun<? super U, ? super U, ? extends U> reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceEntriesTask<K, V, U>(map, this, b, rights, transformer, reducer)).fork();
  				U r = null, u;
  				V v;
  				while ((v = advance()) != null) {
  					if ((u = transformer.apply(entryFor((K) nextKey, v))) != null)
  						r = (r == null) ? u : reducer.apply(r, u);
  				}
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceEntriesTask<K, V, U> t = (MapReduceEntriesTask<K, V, U>) c, s = t.rights;
  					while (s != null) {
  						U tr, sr;
  						if ((sr = s.result) != null)
  							t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr));
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceMappingsTask<K, V, U> extends Traverser<K, V, U> {
  
  		final BiFun<? super K, ? super V, ? extends U> transformer;
  		final BiFun<? super U, ? super U, ? extends U> reducer;
  		U result;
  		MapReduceMappingsTask<K, V, U> rights, nextRight;
  
  		MapReduceMappingsTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceMappingsTask<K, V, U> nextRight, BiFun<? super K, ? super V, ? extends U> transformer,
  				BiFun<? super U, ? super U, ? extends U> reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final U getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final BiFun<? super K, ? super V, ? extends U> transformer;
  			final BiFun<? super U, ? super U, ? extends U> reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceMappingsTask<K, V, U>(map, this, b, rights, transformer, reducer)).fork();
  				U r = null, u;
  				V v;
  				while ((v = advance()) != null) {
  					if ((u = transformer.apply((K) nextKey, v)) != null)
  						r = (r == null) ? u : reducer.apply(r, u);
  				}
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceMappingsTask<K, V, U> t = (MapReduceMappingsTask<K, V, U>) c, s = t.rights;
  					while (s != null) {
  						U tr, sr;
  						if ((sr = s.result) != null)
  							t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr));
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceKeysToDoubleTask<K, V> extends Traverser<K, V, Double> {
  
  		final ObjectToDouble<? super K> transformer;
  		final DoubleByDoubleToDouble reducer;
  		final double basis;
  		double result;
  		MapReduceKeysToDoubleTask<K, V> rights, nextRight;
  
  		MapReduceKeysToDoubleTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceKeysToDoubleTask<K, V> nextRight, ObjectToDouble<? super K> transformer, double basis,
  				DoubleByDoubleToDouble reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Double getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectToDouble<? super K> transformer;
  			final DoubleByDoubleToDouble reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				double r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceKeysToDoubleTask<K, V>(map, this, b, rights, transformer, r, reducer))
  							.fork();
  				while (advance() != null)
  					r = reducer.apply(r, transformer.apply((K) nextKey));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceKeysToDoubleTask<K, V> t = (MapReduceKeysToDoubleTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceValuesToDoubleTask<K, V> extends Traverser<K, V, Double> {
  
  		final ObjectToDouble<? super V> transformer;
  		final DoubleByDoubleToDouble reducer;
  		final double basis;
  		double result;
  		MapReduceValuesToDoubleTask<K, V> rights, nextRight;
  
  		MapReduceValuesToDoubleTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceValuesToDoubleTask<K, V> nextRight, ObjectToDouble<? super V> transformer, double basis,
  				DoubleByDoubleToDouble reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Double getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectToDouble<? super V> transformer;
  			final DoubleByDoubleToDouble reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				double r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceValuesToDoubleTask<K, V>(map, this, b, rights, transformer, r, reducer))
  							.fork();
  				V v;
  				while ((v = advance()) != null)
  					r = reducer.apply(r, transformer.apply(v));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceValuesToDoubleTask<K, V> t = (MapReduceValuesToDoubleTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceEntriesToDoubleTask<K, V> extends Traverser<K, V, Double> {
  
  		final ObjectToDouble<Map.Entry<K, V>> transformer;
  		final DoubleByDoubleToDouble reducer;
  		final double basis;
  		double result;
  		MapReduceEntriesToDoubleTask<K, V> rights, nextRight;
  
  		MapReduceEntriesToDoubleTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceEntriesToDoubleTask<K, V> nextRight, ObjectToDouble<Map.Entry<K, V>> transformer, double basis,
  				DoubleByDoubleToDouble reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Double getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectToDouble<Map.Entry<K, V>> transformer;
  			final DoubleByDoubleToDouble reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				double r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceEntriesToDoubleTask<K, V>(map, this, b, rights, transformer, r, reducer))
  							.fork();
  				V v;
  				while ((v = advance()) != null)
  					r = reducer.apply(r, transformer.apply(entryFor((K) nextKey, v)));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceEntriesToDoubleTask<K, V> t = (MapReduceEntriesToDoubleTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceMappingsToDoubleTask<K, V> extends Traverser<K, V, Double> {
  
  		final ObjectByObjectToDouble<? super K, ? super V> transformer;
  		final DoubleByDoubleToDouble reducer;
  		final double basis;
  		double result;
  		MapReduceMappingsToDoubleTask<K, V> rights, nextRight;
  
  		MapReduceMappingsToDoubleTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceMappingsToDoubleTask<K, V> nextRight, ObjectByObjectToDouble<? super K, ? super V> transformer,
  				double basis, DoubleByDoubleToDouble reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Double getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectByObjectToDouble<? super K, ? super V> transformer;
  			final DoubleByDoubleToDouble reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				double r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceMappingsToDoubleTask<K, V>(map, this, b, rights, transformer, r, reducer))
  							.fork();
  				V v;
  				while ((v = advance()) != null)
  					r = reducer.apply(r, transformer.apply((K) nextKey, v));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceMappingsToDoubleTask<K, V> t = (MapReduceMappingsToDoubleTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceKeysToLongTask<K, V> extends Traverser<K, V, Long> {
  
  		final ObjectToLong<? super K> transformer;
  		final LongByLongToLong reducer;
  		final long basis;
  		long result;
  		MapReduceKeysToLongTask<K, V> rights, nextRight;
  
  		MapReduceKeysToLongTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceKeysToLongTask<K, V> nextRight, ObjectToLong<? super K> transformer, long basis,
  				LongByLongToLong reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Long getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectToLong<? super K> transformer;
  			final LongByLongToLong reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				long r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceKeysToLongTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
  				while (advance() != null)
  					r = reducer.apply(r, transformer.apply((K) nextKey));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceKeysToLongTask<K, V> t = (MapReduceKeysToLongTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceValuesToLongTask<K, V> extends Traverser<K, V, Long> {
  
  		final ObjectToLong<? super V> transformer;
  		final LongByLongToLong reducer;
  		final long basis;
  		long result;
  		MapReduceValuesToLongTask<K, V> rights, nextRight;
  
  		MapReduceValuesToLongTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceValuesToLongTask<K, V> nextRight, ObjectToLong<? super V> transformer, long basis,
  				LongByLongToLong reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Long getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectToLong<? super V> transformer;
  			final LongByLongToLong reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				long r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceValuesToLongTask<K, V>(map, this, b, rights, transformer, r, reducer))
  							.fork();
  				V v;
  				while ((v = advance()) != null)
  					r = reducer.apply(r, transformer.apply(v));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceValuesToLongTask<K, V> t = (MapReduceValuesToLongTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceEntriesToLongTask<K, V> extends Traverser<K, V, Long> {
  
  		final ObjectToLong<Map.Entry<K, V>> transformer;
  		final LongByLongToLong reducer;
  		final long basis;
  		long result;
  		MapReduceEntriesToLongTask<K, V> rights, nextRight;
  
  		MapReduceEntriesToLongTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceEntriesToLongTask<K, V> nextRight, ObjectToLong<Map.Entry<K, V>> transformer, long basis,
  				LongByLongToLong reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Long getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectToLong<Map.Entry<K, V>> transformer;
  			final LongByLongToLong reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				long r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceEntriesToLongTask<K, V>(map, this, b, rights, transformer, r, reducer))
  							.fork();
  				V v;
  				while ((v = advance()) != null)
  					r = reducer.apply(r, transformer.apply(entryFor((K) nextKey, v)));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceEntriesToLongTask<K, V> t = (MapReduceEntriesToLongTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceMappingsToLongTask<K, V> extends Traverser<K, V, Long> {
  
  		final ObjectByObjectToLong<? super K, ? super V> transformer;
  		final LongByLongToLong reducer;
  		final long basis;
  		long result;
  		MapReduceMappingsToLongTask<K, V> rights, nextRight;
  
  		MapReduceMappingsToLongTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceMappingsToLongTask<K, V> nextRight, ObjectByObjectToLong<? super K, ? super V> transformer,
  				long basis, LongByLongToLong reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Long getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectByObjectToLong<? super K, ? super V> transformer;
  			final LongByLongToLong reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				long r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceMappingsToLongTask<K, V>(map, this, b, rights, transformer, r, reducer))
  							.fork();
  				V v;
  				while ((v = advance()) != null)
  					r = reducer.apply(r, transformer.apply((K) nextKey, v));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceMappingsToLongTask<K, V> t = (MapReduceMappingsToLongTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceKeysToIntTask<K, V> extends Traverser<K, V, Integer> {
  
  		final ObjectToInt<? super K> transformer;
  		final IntByIntToInt reducer;
  		final int basis;
  		int result;
  		MapReduceKeysToIntTask<K, V> rights, nextRight;
  
  		MapReduceKeysToIntTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceKeysToIntTask<K, V> nextRight, ObjectToInt<? super K> transformer, int basis,
  				IntByIntToInt reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Integer getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectToInt<? super K> transformer;
  			final IntByIntToInt reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				int r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceKeysToIntTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
  				while (advance() != null)
  					r = reducer.apply(r, transformer.apply((K) nextKey));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceKeysToIntTask<K, V> t = (MapReduceKeysToIntTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceValuesToIntTask<K, V> extends Traverser<K, V, Integer> {
  
  		final ObjectToInt<? super V> transformer;
  		final IntByIntToInt reducer;
  		final int basis;
  		int result;
  		MapReduceValuesToIntTask<K, V> rights, nextRight;
  
  		MapReduceValuesToIntTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceValuesToIntTask<K, V> nextRight, ObjectToInt<? super V> transformer, int basis,
  				IntByIntToInt reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Integer getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectToInt<? super V> transformer;
  			final IntByIntToInt reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				int r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceValuesToIntTask<K, V>(map, this, b, rights, transformer, r, reducer)).fork();
  				V v;
  				while ((v = advance()) != null)
  					r = reducer.apply(r, transformer.apply(v));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceValuesToIntTask<K, V> t = (MapReduceValuesToIntTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceEntriesToIntTask<K, V> extends Traverser<K, V, Integer> {
  
  		final ObjectToInt<Map.Entry<K, V>> transformer;
  		final IntByIntToInt reducer;
  		final int basis;
  		int result;
  		MapReduceEntriesToIntTask<K, V> rights, nextRight;
  
  		MapReduceEntriesToIntTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceEntriesToIntTask<K, V> nextRight, ObjectToInt<Map.Entry<K, V>> transformer, int basis,
  				IntByIntToInt reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Integer getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectToInt<Map.Entry<K, V>> transformer;
  			final IntByIntToInt reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				int r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceEntriesToIntTask<K, V>(map, this, b, rights, transformer, r, reducer))
  							.fork();
  				V v;
  				while ((v = advance()) != null)
  					r = reducer.apply(r, transformer.apply(entryFor((K) nextKey, v)));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceEntriesToIntTask<K, V> t = (MapReduceEntriesToIntTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	@SuppressWarnings("serial")
  	static final class MapReduceMappingsToIntTask<K, V> extends Traverser<K, V, Integer> {
  
  		final ObjectByObjectToInt<? super K, ? super V> transformer;
  		final IntByIntToInt reducer;
  		final int basis;
  		int result;
  		MapReduceMappingsToIntTask<K, V> rights, nextRight;
  
  		MapReduceMappingsToIntTask(ConcurrentHashMapV8<K, V> m, Traverser<K, V, ?> p, int b,
  				MapReduceMappingsToIntTask<K, V> nextRight, ObjectByObjectToInt<? super K, ? super V> transformer,
  				int basis, IntByIntToInt reducer) {
  			super(m, p, b);
  			this.nextRight = nextRight;
  			this.transformer = transformer;
  			this.basis = basis;
  			this.reducer = reducer;
  		}
  
  		@Override
  		public final Integer getRawResult() {
  			return result;
  		}
  
  		@Override
  		@SuppressWarnings("unchecked")
  		public final void compute() {
  			final ObjectByObjectToInt<? super K, ? super V> transformer;
  			final IntByIntToInt reducer;
  			if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) {
  				int r = this.basis;
  				for (int b; (b = preSplit()) > 0;)
  					(rights = new MapReduceMappingsToIntTask<K, V>(map, this, b, rights, transformer, r, reducer))
  							.fork();
  				V v;
  				while ((v = advance()) != null)
  					r = reducer.apply(r, transformer.apply((K) nextKey, v));
  				result = r;
  				CountedCompleter<?> c;
  				for (c = firstComplete(); c != null; c = c.nextComplete()) {
  					MapReduceMappingsToIntTask<K, V> t = (MapReduceMappingsToIntTask<K, V>) c, s = t.rights;
  					while (s != null) {
  						t.result = reducer.apply(t.result, s.result);
  						s = t.rights = s.nextRight;
  					}
  				}
  			}
  		}
  	}
  
  	// Unsafe mechanics
  	private static final sun.misc.Unsafe U;
  	private static final long SIZECTL;
  	private static final long TRANSFERINDEX;
  	private static final long TRANSFERORIGIN;
  	private static final long BASECOUNT;
  	private static final long COUNTERBUSY;
  	private static final long CELLVALUE;
  	private static final long ABASE;
  	private static final int ASHIFT;
  
  	static {
  		try {
  			U = getUnsafe();
  			Class<?> k = ConcurrentHashMapV8.class;
  			SIZECTL = U.objectFieldOffset(k.getDeclaredField("sizeCtl"));
  			TRANSFERINDEX = U.objectFieldOffset(k.getDeclaredField("transferIndex"));
  			TRANSFERORIGIN = U.objectFieldOffset(k.getDeclaredField("transferOrigin"));
  			BASECOUNT = U.objectFieldOffset(k.getDeclaredField("baseCount"));
  			COUNTERBUSY = U.objectFieldOffset(k.getDeclaredField("counterBusy"));
  			Class<?> ck = CounterCell.class;
  			CELLVALUE = U.objectFieldOffset(ck.getDeclaredField("value"));
  			Class<?> sc = Node[].class;
  			ABASE = U.arrayBaseOffset(sc);
  			int scale = U.arrayIndexScale(sc);
  			if ((scale & (scale - 1)) != 0)
  				throw new Error("data type scale not a power of two");
  			ASHIFT = 31 - Integer.numberOfLeadingZeros(scale);
  		} catch (Exception e) {
  			throw new Error(e);
  		}
  	}
  
  	/**
  	 * Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package.
  	 * Replace with a simple call to Unsafe.getUnsafe when integrating into a
  	 * jdk.
  	 *
  	 * @return a sun.misc.Unsafe
  	 */
  	private static sun.misc.Unsafe getUnsafe() {
  		try {
  			return sun.misc.Unsafe.getUnsafe();
  		} catch (SecurityException tryReflectionInstead) {
  		}
  		try {
  			return java.security.AccessController
  					.doPrivileged(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
  						@Override
  						public sun.misc.Unsafe run() throws Exception {
  							Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
  							for (java.lang.reflect.Field f : k.getDeclaredFields()) {
  								f.setAccessible(true);
  								Object x = f.get(null);
  								if (k.isInstance(x))
  									return k.cast(x);
  							}
  							throw new NoSuchFieldError("the Unsafe");
  						}
  					});
  		} catch (java.security.PrivilegedActionException e) {
  			throw new RuntimeException("Could not initialize intrinsics", e.getCause());
  		}
  	}
  }
  