content: /*
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code 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
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  /*
   * This file is available under and governed by the GNU General Public
   * License version 2 only, as published by the Free Software Foundation.
   * However, the following notice accompanied the original version of this
   * file:
   *
   * 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 java.util.concurrent;
  
  import java.util.Deque;
  import java.util.Iterator;
  import java.util.NoSuchElementException;
  
  // BEGIN android-note
  // fixed framework docs link to "Collection#optional"
  // END android-note
  
  /**
   * A {@link Deque} that additionally supports blocking operations that wait
   * for the deque to become non-empty when retrieving an element, and wait for
   * space to become available in the deque when storing an element.
   *
   * <p>{@code BlockingDeque} methods come in four forms, with different ways
   * of handling operations that cannot be satisfied immediately, but may be
   * satisfied at some point in the future:
   * one throws an exception, the second returns a special value (either
   * {@code null} or {@code false}, depending on the operation), the third
   * blocks the current thread indefinitely until the operation can succeed,
   * and the fourth blocks for only a given maximum time limit before giving
   * up.  These methods are summarized in the following table:
   *
   * <table BORDER CELLPADDING=3 CELLSPACING=1>
   * <caption>Summary of BlockingDeque methods</caption>
   *  <tr>
   *    <td ALIGN=CENTER COLSPAN = 5> <b>First Element (Head)</b></td>
   *  </tr>
   *  <tr>
   *    <td></td>
   *    <td ALIGN=CENTER><em>Throws exception</em></td>
   *    <td ALIGN=CENTER><em>Special value</em></td>
   *    <td ALIGN=CENTER><em>Blocks</em></td>
   *    <td ALIGN=CENTER><em>Times out</em></td>
   *  </tr>
   *  <tr>
   *    <td><b>Insert</b></td>
   *    <td>{@link #addFirst addFirst(e)}</td>
   *    <td>{@link #offerFirst(Object) offerFirst(e)}</td>
   *    <td>{@link #putFirst putFirst(e)}</td>
   *    <td>{@link #offerFirst(Object, long, TimeUnit) offerFirst(e, time, unit)}</td>
   *  </tr>
   *  <tr>
   *    <td><b>Remove</b></td>
   *    <td>{@link #removeFirst removeFirst()}</td>
   *    <td>{@link #pollFirst pollFirst()}</td>
   *    <td>{@link #takeFirst takeFirst()}</td>
   *    <td>{@link #pollFirst(long, TimeUnit) pollFirst(time, unit)}</td>
   *  </tr>
   *  <tr>
   *    <td><b>Examine</b></td>
   *    <td>{@link #getFirst getFirst()}</td>
   *    <td>{@link #peekFirst peekFirst()}</td>
   *    <td><em>not applicable</em></td>
   *    <td><em>not applicable</em></td>
   *  </tr>
   *  <tr>
   *    <td ALIGN=CENTER COLSPAN = 5> <b>Last Element (Tail)</b></td>
   *  </tr>
   *  <tr>
   *    <td></td>
   *    <td ALIGN=CENTER><em>Throws exception</em></td>
   *    <td ALIGN=CENTER><em>Special value</em></td>
   *    <td ALIGN=CENTER><em>Blocks</em></td>
   *    <td ALIGN=CENTER><em>Times out</em></td>
   *  </tr>
   *  <tr>
   *    <td><b>Insert</b></td>
   *    <td>{@link #addLast addLast(e)}</td>
   *    <td>{@link #offerLast(Object) offerLast(e)}</td>
   *    <td>{@link #putLast putLast(e)}</td>
   *    <td>{@link #offerLast(Object, long, TimeUnit) offerLast(e, time, unit)}</td>
   *  </tr>
   *  <tr>
   *    <td><b>Remove</b></td>
   *    <td>{@link #removeLast() removeLast()}</td>
   *    <td>{@link #pollLast() pollLast()}</td>
   *    <td>{@link #takeLast takeLast()}</td>
   *    <td>{@link #pollLast(long, TimeUnit) pollLast(time, unit)}</td>
   *  </tr>
   *  <tr>
   *    <td><b>Examine</b></td>
   *    <td>{@link #getLast getLast()}</td>
   *    <td>{@link #peekLast peekLast()}</td>
   *    <td><em>not applicable</em></td>
   *    <td><em>not applicable</em></td>
   *  </tr>
   * </table>
   *
   * <p>Like any {@link BlockingQueue}, a {@code BlockingDeque} is thread safe,
   * does not permit null elements, and may (or may not) be
   * capacity-constrained.
   *
   * <p>A {@code BlockingDeque} implementation may be used directly as a FIFO
   * {@code BlockingQueue}. The methods inherited from the
   * {@code BlockingQueue} interface are precisely equivalent to
   * {@code BlockingDeque} methods as indicated in the following table:
   *
   * <table BORDER CELLPADDING=3 CELLSPACING=1>
   * <caption>Comparison of BlockingQueue and BlockingDeque methods</caption>
   *  <tr>
   *    <td ALIGN=CENTER> <b>{@code BlockingQueue} Method</b></td>
   *    <td ALIGN=CENTER> <b>Equivalent {@code BlockingDeque} Method</b></td>
   *  </tr>
   *  <tr>
   *    <td ALIGN=CENTER COLSPAN = 2> <b>Insert</b></td>
   *  </tr>
   *  <tr>
   *    <td>{@link #add(Object) add(e)}</td>
   *    <td>{@link #addLast(Object) addLast(e)}</td>
   *  </tr>
   *  <tr>
   *    <td>{@link #offer(Object) offer(e)}</td>
   *    <td>{@link #offerLast(Object) offerLast(e)}</td>
   *  </tr>
   *  <tr>
   *    <td>{@link #put(Object) put(e)}</td>
   *    <td>{@link #putLast(Object) putLast(e)}</td>
   *  </tr>
   *  <tr>
   *    <td>{@link #offer(Object, long, TimeUnit) offer(e, time, unit)}</td>
   *    <td>{@link #offerLast(Object, long, TimeUnit) offerLast(e, time, unit)}</td>
   *  </tr>
   *  <tr>
   *    <td ALIGN=CENTER COLSPAN = 2> <b>Remove</b></td>
   *  </tr>
   *  <tr>
   *    <td>{@link #remove() remove()}</td>
   *    <td>{@link #removeFirst() removeFirst()}</td>
   *  </tr>
   *  <tr>
   *    <td>{@link #poll() poll()}</td>
   *    <td>{@link #pollFirst() pollFirst()}</td>
   *  </tr>
   *  <tr>
   *    <td>{@link #take() take()}</td>
   *    <td>{@link #takeFirst() takeFirst()}</td>
   *  </tr>
   *  <tr>
   *    <td>{@link #poll(long, TimeUnit) poll(time, unit)}</td>
   *    <td>{@link #pollFirst(long, TimeUnit) pollFirst(time, unit)}</td>
   *  </tr>
   *  <tr>
   *    <td ALIGN=CENTER COLSPAN = 2> <b>Examine</b></td>
   *  </tr>
   *  <tr>
   *    <td>{@link #element() element()}</td>
   *    <td>{@link #getFirst() getFirst()}</td>
   *  </tr>
   *  <tr>
   *    <td>{@link #peek() peek()}</td>
   *    <td>{@link #peekFirst() peekFirst()}</td>
   *  </tr>
   * </table>
   *
   * <p>Memory consistency effects: As with other concurrent
   * collections, actions in a thread prior to placing an object into a
   * {@code BlockingDeque}
   * <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a>
   * actions subsequent to the access or removal of that element from
   * the {@code BlockingDeque} in another thread.
   *
   * <p>This interface is a member of the
   * <a href="{@docRoot}/../technotes/guides/collections/index.html">
   * Java Collections Framework</a>.
   *
   * @since 1.6
   * @author Doug Lea
   * @param <E> the type of elements held in this deque
   */
  public interface BlockingDeque<E> extends BlockingQueue<E>, Deque<E> {
      /*
       * We have "diamond" multiple interface inheritance here, and that
       * introduces ambiguities.  Methods might end up with different
       * specs depending on the branch chosen by javadoc.  Thus a lot of
       * methods specs here are copied from superinterfaces.
       */
  
      /**
       * Inserts the specified element at the front of this deque if it is
       * possible to do so immediately without violating capacity restrictions,
       * throwing an {@code IllegalStateException} if no space is currently
       * available.  When using a capacity-restricted deque, it is generally
       * preferable to use {@link #offerFirst(Object) offerFirst}.
       *
       * @param e the element to add
       * @throws IllegalStateException {@inheritDoc}
       * @throws ClassCastException {@inheritDoc}
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException {@inheritDoc}
       */
      void addFirst(E e);
  
      /**
       * Inserts the specified element at the end of this deque if it is
       * possible to do so immediately without violating capacity restrictions,
       * throwing an {@code IllegalStateException} if no space is currently
       * available.  When using a capacity-restricted deque, it is generally
       * preferable to use {@link #offerLast(Object) offerLast}.
       *
       * @param e the element to add
       * @throws IllegalStateException {@inheritDoc}
       * @throws ClassCastException {@inheritDoc}
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException {@inheritDoc}
       */
      void addLast(E e);
  
      /**
       * Inserts the specified element at the front of this deque if it is
       * possible to do so immediately without violating capacity restrictions,
       * returning {@code true} upon success and {@code false} if no space is
       * currently available.
       * When using a capacity-restricted deque, this method is generally
       * preferable to the {@link #addFirst(Object) addFirst} method, which can
       * fail to insert an element only by throwing an exception.
       *
       * @param e the element to add
       * @throws ClassCastException {@inheritDoc}
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException {@inheritDoc}
       */
      boolean offerFirst(E e);
  
      /**
       * Inserts the specified element at the end of this deque if it is
       * possible to do so immediately without violating capacity restrictions,
       * returning {@code true} upon success and {@code false} if no space is
       * currently available.
       * When using a capacity-restricted deque, this method is generally
       * preferable to the {@link #addLast(Object) addLast} method, which can
       * fail to insert an element only by throwing an exception.
       *
       * @param e the element to add
       * @throws ClassCastException {@inheritDoc}
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException {@inheritDoc}
       */
      boolean offerLast(E e);
  
      /**
       * Inserts the specified element at the front of this deque,
       * waiting if necessary for space to become available.
       *
       * @param e the element to add
       * @throws InterruptedException if interrupted while waiting
       * @throws ClassCastException if the class of the specified element
       *         prevents it from being added to this deque
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException if some property of the specified
       *         element prevents it from being added to this deque
       */
      void putFirst(E e) throws InterruptedException;
  
      /**
       * Inserts the specified element at the end of this deque,
       * waiting if necessary for space to become available.
       *
       * @param e the element to add
       * @throws InterruptedException if interrupted while waiting
       * @throws ClassCastException if the class of the specified element
       *         prevents it from being added to this deque
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException if some property of the specified
       *         element prevents it from being added to this deque
       */
      void putLast(E e) throws InterruptedException;
  
      /**
       * Inserts the specified element at the front of this deque,
       * waiting up to the specified wait time if necessary for space to
       * become available.
       *
       * @param e the element to add
       * @param timeout how long to wait before giving up, in units of
       *        {@code unit}
       * @param unit a {@code TimeUnit} determining how to interpret the
       *        {@code timeout} parameter
       * @return {@code true} if successful, or {@code false} if
       *         the specified waiting time elapses before space is available
       * @throws InterruptedException if interrupted while waiting
       * @throws ClassCastException if the class of the specified element
       *         prevents it from being added to this deque
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException if some property of the specified
       *         element prevents it from being added to this deque
       */
      boolean offerFirst(E e, long timeout, TimeUnit unit)
          throws InterruptedException;
  
      /**
       * Inserts the specified element at the end of this deque,
       * waiting up to the specified wait time if necessary for space to
       * become available.
       *
       * @param e the element to add
       * @param timeout how long to wait before giving up, in units of
       *        {@code unit}
       * @param unit a {@code TimeUnit} determining how to interpret the
       *        {@code timeout} parameter
       * @return {@code true} if successful, or {@code false} if
       *         the specified waiting time elapses before space is available
       * @throws InterruptedException if interrupted while waiting
       * @throws ClassCastException if the class of the specified element
       *         prevents it from being added to this deque
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException if some property of the specified
       *         element prevents it from being added to this deque
       */
      boolean offerLast(E e, long timeout, TimeUnit unit)
          throws InterruptedException;
  
      /**
       * Retrieves and removes the first element of this deque, waiting
       * if necessary until an element becomes available.
       *
       * @return the head of this deque
       * @throws InterruptedException if interrupted while waiting
       */
      E takeFirst() throws InterruptedException;
  
      /**
       * Retrieves and removes the last element of this deque, waiting
       * if necessary until an element becomes available.
       *
       * @return the tail of this deque
       * @throws InterruptedException if interrupted while waiting
       */
      E takeLast() throws InterruptedException;
  
      /**
       * Retrieves and removes the first element of this deque, waiting
       * up to the specified wait time if necessary for an element to
       * become available.
       *
       * @param timeout how long to wait before giving up, in units of
       *        {@code unit}
       * @param unit a {@code TimeUnit} determining how to interpret the
       *        {@code timeout} parameter
       * @return the head of this deque, or {@code null} if the specified
       *         waiting time elapses before an element is available
       * @throws InterruptedException if interrupted while waiting
       */
      E pollFirst(long timeout, TimeUnit unit)
          throws InterruptedException;
  
      /**
       * Retrieves and removes the last element of this deque, waiting
       * up to the specified wait time if necessary for an element to
       * become available.
       *
       * @param timeout how long to wait before giving up, in units of
       *        {@code unit}
       * @param unit a {@code TimeUnit} determining how to interpret the
       *        {@code timeout} parameter
       * @return the tail of this deque, or {@code null} if the specified
       *         waiting time elapses before an element is available
       * @throws InterruptedException if interrupted while waiting
       */
      E pollLast(long timeout, TimeUnit unit)
          throws InterruptedException;
  
      /**
       * Removes the first occurrence of the specified element from this deque.
       * If the deque does not contain the element, it is unchanged.
       * More formally, removes the first element {@code e} such that
       * {@code o.equals(e)} (if such an element exists).
       * Returns {@code true} if this deque contained the specified element
       * (or equivalently, if this deque changed as a result of the call).
       *
       * @param o element to be removed from this deque, if present
       * @return {@code true} if an element was removed as a result of this call
       * @throws ClassCastException if the class of the specified element
       *         is incompatible with this deque
       * (<a href="../Collection.html#optional-restrictions">optional</a>)
       * @throws NullPointerException if the specified element is null
       * (<a href="../Collection.html#optional-restrictions">optional</a>)
       */
      boolean removeFirstOccurrence(Object o);
  
      /**
       * Removes the last occurrence of the specified element from this deque.
       * If the deque does not contain the element, it is unchanged.
       * More formally, removes the last element {@code e} such that
       * {@code o.equals(e)} (if such an element exists).
       * Returns {@code true} if this deque contained the specified element
       * (or equivalently, if this deque changed as a result of the call).
       *
       * @param o element to be removed from this deque, if present
       * @return {@code true} if an element was removed as a result of this call
       * @throws ClassCastException if the class of the specified element
       *         is incompatible with this deque
       * (<a href="../Collection.html#optional-restrictions">optional</a>)
       * @throws NullPointerException if the specified element is null
       * (<a href="../Collection.html#optional-restrictions">optional</a>)
       */
      boolean removeLastOccurrence(Object o);
  
      // *** BlockingQueue methods ***
  
      /**
       * Inserts the specified element into the queue represented by this deque
       * (in other words, at the tail of this deque) if it is possible to do so
       * immediately without violating capacity restrictions, returning
       * {@code true} upon success and throwing an
       * {@code IllegalStateException} if no space is currently available.
       * When using a capacity-restricted deque, it is generally preferable to
       * use {@link #offer(Object) offer}.
       *
       * <p>This method is equivalent to {@link #addLast(Object) addLast}.
       *
       * @param e the element to add
       * @throws IllegalStateException {@inheritDoc}
       * @throws ClassCastException if the class of the specified element
       *         prevents it from being added to this deque
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException if some property of the specified
       *         element prevents it from being added to this deque
       */
      boolean add(E e);
  
      /**
       * Inserts the specified element into the queue represented by this deque
       * (in other words, at the tail of this deque) if it is possible to do so
       * immediately without violating capacity restrictions, returning
       * {@code true} upon success and {@code false} if no space is currently
       * available.  When using a capacity-restricted deque, this method is
       * generally preferable to the {@link #add} method, which can fail to
       * insert an element only by throwing an exception.
       *
       * <p>This method is equivalent to {@link #offerLast(Object) offerLast}.
       *
       * @param e the element to add
       * @throws ClassCastException if the class of the specified element
       *         prevents it from being added to this deque
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException if some property of the specified
       *         element prevents it from being added to this deque
       */
      boolean offer(E e);
  
      /**
       * Inserts the specified element into the queue represented by this deque
       * (in other words, at the tail of this deque), waiting if necessary for
       * space to become available.
       *
       * <p>This method is equivalent to {@link #putLast(Object) putLast}.
       *
       * @param e the element to add
       * @throws InterruptedException {@inheritDoc}
       * @throws ClassCastException if the class of the specified element
       *         prevents it from being added to this deque
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException if some property of the specified
       *         element prevents it from being added to this deque
       */
      void put(E e) throws InterruptedException;
  
      /**
       * Inserts the specified element into the queue represented by this deque
       * (in other words, at the tail of this deque), waiting up to the
       * specified wait time if necessary for space to become available.
       *
       * <p>This method is equivalent to
       * {@link #offerLast(Object,long,TimeUnit) offerLast}.
       *
       * @param e the element to add
       * @return {@code true} if the element was added to this deque, else
       *         {@code false}
       * @throws InterruptedException {@inheritDoc}
       * @throws ClassCastException if the class of the specified element
       *         prevents it from being added to this deque
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException if some property of the specified
       *         element prevents it from being added to this deque
       */
      boolean offer(E e, long timeout, TimeUnit unit)
          throws InterruptedException;
  
      /**
       * Retrieves and removes the head of the queue represented by this deque
       * (in other words, the first element of this deque).
       * This method differs from {@link #poll poll} only in that it
       * throws an exception if this deque is empty.
       *
       * <p>This method is equivalent to {@link #removeFirst() removeFirst}.
       *
       * @return the head of the queue represented by this deque
       * @throws NoSuchElementException if this deque is empty
       */
      E remove();
  
      /**
       * Retrieves and removes the head of the queue represented by this deque
       * (in other words, the first element of this deque), or returns
       * {@code null} if this deque is empty.
       *
       * <p>This method is equivalent to {@link #pollFirst()}.
       *
       * @return the head of this deque, or {@code null} if this deque is empty
       */
      E poll();
  
      /**
       * Retrieves and removes the head of the queue represented by this deque
       * (in other words, the first element of this deque), waiting if
       * necessary until an element becomes available.
       *
       * <p>This method is equivalent to {@link #takeFirst() takeFirst}.
       *
       * @return the head of this deque
       * @throws InterruptedException if interrupted while waiting
       */
      E take() throws InterruptedException;
  
      /**
       * Retrieves and removes the head of the queue represented by this deque
       * (in other words, the first element of this deque), waiting up to the
       * specified wait time if necessary for an element to become available.
       *
       * <p>This method is equivalent to
       * {@link #pollFirst(long,TimeUnit) pollFirst}.
       *
       * @return the head of this deque, or {@code null} if the
       *         specified waiting time elapses before an element is available
       * @throws InterruptedException if interrupted while waiting
       */
      E poll(long timeout, TimeUnit unit)
          throws InterruptedException;
  
      /**
       * Retrieves, but does not remove, the head of the queue represented by
       * this deque (in other words, the first element of this deque).
       * This method differs from {@link #peek peek} only in that it throws an
       * exception if this deque is empty.
       *
       * <p>This method is equivalent to {@link #getFirst() getFirst}.
       *
       * @return the head of this deque
       * @throws NoSuchElementException if this deque is empty
       */
      E element();
  
      /**
       * Retrieves, but does not remove, the head of the queue represented by
       * this deque (in other words, the first element of this deque), or
       * returns {@code null} if this deque is empty.
       *
       * <p>This method is equivalent to {@link #peekFirst() peekFirst}.
       *
       * @return the head of this deque, or {@code null} if this deque is empty
       */
      E peek();
  
      /**
       * Removes the first occurrence of the specified element from this deque.
       * If the deque does not contain the element, it is unchanged.
       * More formally, removes the first element {@code e} such that
       * {@code o.equals(e)} (if such an element exists).
       * Returns {@code true} if this deque contained the specified element
       * (or equivalently, if this deque changed as a result of the call).
       *
       * <p>This method is equivalent to
       * {@link #removeFirstOccurrence(Object) removeFirstOccurrence}.
       *
       * @param o element to be removed from this deque, if present
       * @return {@code true} if this deque changed as a result of the call
       * @throws ClassCastException if the class of the specified element
       *         is incompatible with this deque
       * (<a href="../Collection.html#optional-restrictions">optional</a>)
       * @throws NullPointerException if the specified element is null
       * (<a href="../Collection.html#optional-restrictions">optional</a>)
       */
      boolean remove(Object o);
  
      /**
       * Returns {@code true} if this deque contains the specified element.
       * More formally, returns {@code true} if and only if this deque contains
       * at least one element {@code e} such that {@code o.equals(e)}.
       *
       * @param o object to be checked for containment in this deque
       * @return {@code true} if this deque contains the specified element
       * @throws ClassCastException if the class of the specified element
       *         is incompatible with this deque
       * (<a href="../Collection.html#optional-restrictions">optional</a>)
       * @throws NullPointerException if the specified element is null
       * (<a href="../Collection.html#optional-restrictions">optional</a>)
       */
      boolean contains(Object o);
  
      /**
       * Returns the number of elements in this deque.
       *
       * @return the number of elements in this deque
       */
      int size();
  
      /**
       * Returns an iterator over the elements in this deque in proper sequence.
       * The elements will be returned in order from first (head) to last (tail).
       *
       * @return an iterator over the elements in this deque in proper sequence
       */
      Iterator<E> iterator();
  
      // *** Stack methods ***
  
      /**
       * Pushes an element onto the stack represented by this deque (in other
       * words, at the head of this deque) if it is possible to do so
       * immediately without violating capacity restrictions, throwing an
       * {@code IllegalStateException} if no space is currently available.
       *
       * <p>This method is equivalent to {@link #addFirst(Object) addFirst}.
       *
       * @throws IllegalStateException {@inheritDoc}
       * @throws ClassCastException {@inheritDoc}
       * @throws NullPointerException if the specified element is null
       * @throws IllegalArgumentException {@inheritDoc}
       */
      void push(E e);
  }
  