content: /*
   * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
   * 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.
   */
  
  package java.util;
  import java.io.*;
  import java.util.concurrent.atomic.AtomicLong;
  import java.util.function.DoubleConsumer;
  import java.util.function.IntConsumer;
  import java.util.function.LongConsumer;
  import java.util.stream.DoubleStream;
  import java.util.stream.IntStream;
  import java.util.stream.LongStream;
  import java.util.stream.StreamSupport;
  
  import sun.misc.Unsafe;
  
  /**
   * An instance of this class is used to generate a stream of
   * pseudorandom numbers. The class uses a 48-bit seed, which is
   * modified using a linear congruential formula. (See Donald Knuth,
   * <i>The Art of Computer Programming, Volume 2</i>, Section 3.2.1.)
   * <p>
   * If two instances of {@code Random} are created with the same
   * seed, and the same sequence of method calls is made for each, they
   * will generate and return identical sequences of numbers. In order to
   * guarantee this property, particular algorithms are specified for the
   * class {@code Random}. Java implementations must use all the algorithms
   * shown here for the class {@code Random}, for the sake of absolute
   * portability of Java code. However, subclasses of class {@code Random}
   * are permitted to use other algorithms, so long as they adhere to the
   * general contracts for all the methods.
   * <p>
   * The algorithms implemented by class {@code Random} use a
   * {@code protected} utility method that on each invocation can supply
   * up to 32 pseudorandomly generated bits.
   * <p>
   * Many applications will find the method {@link Math#random} simpler to use.
   *
   * <p>Instances of {@code java.util.Random} are threadsafe.
   * However, the concurrent use of the same {@code java.util.Random}
   * instance across threads may encounter contention and consequent
   * poor performance. Consider instead using
   * {@link java.util.concurrent.ThreadLocalRandom} in multithreaded
   * designs.
   *
   * <p>Instances of {@code java.util.Random} are not cryptographically
   * secure.  Consider instead using {@link java.security.SecureRandom} to
   * get a cryptographically secure pseudo-random number generator for use
   * by security-sensitive applications.
   *
   * @author  Frank Yellin
   * @since   1.0
   */
  public
  class Random implements Serializable {
      /** use serialVersionUID from JDK 1.1 for interoperability */
      static final long serialVersionUID = 3905348978240129619L;
  
      /**
       * The internal state associated with this pseudorandom number generator.
       * (The specs for the methods in this class describe the ongoing
       * computation of this value.)
       */
      private final AtomicLong seed;
  
      private static final long multiplier = 0x5DEECE66DL;
      private static final long addend = 0xBL;
      private static final long mask = (1L << 48) - 1;
  
      private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53)
  
      // IllegalArgumentException messages
      static final String BadBound = "bound must be positive";
      static final String BadRange = "bound must be greater than origin";
      static final String BadSize  = "size must be non-negative";
  
      /**
       * Creates a new random number generator. This constructor sets
       * the seed of the random number generator to a value very likely
       * to be distinct from any other invocation of this constructor.
       */
      public Random() {
          this(seedUniquifier() ^ System.nanoTime());
      }
  
      private static long seedUniquifier() {
          // L'Ecuyer, "Tables of Linear Congruential Generators of
          // Different Sizes and Good Lattice Structure", 1999
          for (;;) {
              long current = seedUniquifier.get();
              long next = current * 181783497276652981L;
              if (seedUniquifier.compareAndSet(current, next))
                  return next;
          }
      }
  
      private static final AtomicLong seedUniquifier
          = new AtomicLong(8682522807148012L);
  
      /**
       * Creates a new random number generator using a single {@code long} seed.
       * The seed is the initial value of the internal state of the pseudorandom
       * number generator which is maintained by method {@link #next}.
       *
       * <p>The invocation {@code new Random(seed)} is equivalent to:
       *  <pre> {@code
       * Random rnd = new Random();
       * rnd.setSeed(seed);}</pre>
       *
       * @param seed the initial seed
       * @see   #setSeed(long)
       */
      public Random(long seed) {
          if (getClass() == Random.class)
              this.seed = new AtomicLong(initialScramble(seed));
          else {
              // subclass might have overriden setSeed
              this.seed = new AtomicLong();
              setSeed(seed);
          }
      }
  
      private static long initialScramble(long seed) {
          return (seed ^ multiplier) & mask;
      }
  
      /**
       * Sets the seed of this random number generator using a single
       * {@code long} seed. The general contract of {@code setSeed} is
       * that it alters the state of this random number generator object
       * so as to be in exactly the same state as if it had just been
       * created with the argument {@code seed} as a seed. The method
       * {@code setSeed} is implemented by class {@code Random} by
       * atomically updating the seed to
       *  <pre>{@code (seed ^ 0x5DEECE66DL) & ((1L << 48) - 1)}</pre>
       * and clearing the {@code haveNextNextGaussian} flag used by {@link
       * #nextGaussian}.
       *
       * <p>The implementation of {@code setSeed} by class {@code Random}
       * happens to use only 48 bits of the given seed. In general, however,
       * an overriding method may use all 64 bits of the {@code long}
       * argument as a seed value.
       *
       * @param seed the initial seed
       */
      synchronized public void setSeed(long seed) {
          this.seed.set(initialScramble(seed));
          haveNextNextGaussian = false;
      }
  
      /**
       * Generates the next pseudorandom number. Subclasses should
       * override this, as this is used by all other methods.
       *
       * <p>The general contract of {@code next} is that it returns an
       * {@code int} value and if the argument {@code bits} is between
       * {@code 1} and {@code 32} (inclusive), then that many low-order
       * bits of the returned value will be (approximately) independently
       * chosen bit values, each of which is (approximately) equally
       * likely to be {@code 0} or {@code 1}. The method {@code next} is
       * implemented by class {@code Random} by atomically updating the seed to
       *  <pre>{@code (seed * 0x5DEECE66DL + 0xBL) & ((1L << 48) - 1)}</pre>
       * and returning
       *  <pre>{@code (int)(seed >>> (48 - bits))}.</pre>
       *
       * This is a linear congruential pseudorandom number generator, as
       * defined by D. H. Lehmer and described by Donald E. Knuth in
       * <i>The Art of Computer Programming,</i> Volume 3:
       * <i>Seminumerical Algorithms</i>, section 3.2.1.
       *
       * @param  bits random bits
       * @return the next pseudorandom value from this random number
       *         generator's sequence
       * @since  1.1
       */
      protected int next(int bits) {
          long oldseed, nextseed;
          AtomicLong seed = this.seed;
          do {
              oldseed = seed.get();
              nextseed = (oldseed * multiplier + addend) & mask;
          } while (!seed.compareAndSet(oldseed, nextseed));
          return (int)(nextseed >>> (48 - bits));
      }
  
      /**
       * Generates random bytes and places them into a user-supplied
       * byte array.  The number of random bytes produced is equal to
       * the length of the byte array.
       *
       * <p>The method {@code nextBytes} is implemented by class {@code Random}
       * as if by:
       *  <pre> {@code
       * public void nextBytes(byte[] bytes) {
       *   for (int i = 0; i < bytes.length; )
       *     for (int rnd = nextInt(), n = Math.min(bytes.length - i, 4);
       *          n-- > 0; rnd >>= 8)
       *       bytes[i++] = (byte)rnd;
       * }}</pre>
       *
       * @param  bytes the byte array to fill with random bytes
       * @throws NullPointerException if the byte array is null
       * @since  1.1
       */
      public void nextBytes(byte[] bytes) {
          for (int i = 0, len = bytes.length; i < len; )
              for (int rnd = nextInt(),
                       n = Math.min(len - i, Integer.SIZE/Byte.SIZE);
                   n-- > 0; rnd >>= Byte.SIZE)
                  bytes[i++] = (byte)rnd;
      }
  
      /**
       * The form of nextLong used by LongStream Spliterators.  If
       * origin is greater than bound, acts as unbounded form of
       * nextLong, else as bounded form.
       *
       * @param origin the least value, unless greater than bound
       * @param bound the upper bound (exclusive), must not equal origin
       * @return a pseudorandom value
       */
      final long internalNextLong(long origin, long bound) {
          long r = nextLong();
          if (origin < bound) {
              long n = bound - origin, m = n - 1;
              if ((n & m) == 0L)  // power of two
                  r = (r & m) + origin;
              else if (n > 0L) {  // reject over-represented candidates
                  for (long u = r >>> 1;            // ensure nonnegative
                       u + m - (r = u % n) < 0L;    // rejection check
                       u = nextLong() >>> 1) // retry
                      ;
                  r += origin;
              }
              else {              // range not representable as long
                  while (r < origin || r >= bound)
                      r = nextLong();
              }
          }
          return r;
      }
  
      /**
       * The form of nextInt used by IntStream Spliterators.
       * For the unbounded case: uses nextInt().
       * For the bounded case with representable range: uses nextInt(int bound)
       * For the bounded case with unrepresentable range: uses nextInt()
       *
       * @param origin the least value, unless greater than bound
       * @param bound the upper bound (exclusive), must not equal origin
       * @return a pseudorandom value
       */
      final int internalNextInt(int origin, int bound) {
          if (origin < bound) {
              int n = bound - origin;
              if (n > 0) {
                  return nextInt(n) + origin;
              }
              else {  // range not representable as int
                  int r;
                  do {
                      r = nextInt();
                  } while (r < origin || r >= bound);
                  return r;
              }
          }
          else {
              return nextInt();
          }
      }
  
      /**
       * The form of nextDouble used by DoubleStream Spliterators.
       *
       * @param origin the least value, unless greater than bound
       * @param bound the upper bound (exclusive), must not equal origin
       * @return a pseudorandom value
       */
      final double internalNextDouble(double origin, double bound) {
          double r = nextDouble();
          if (origin < bound) {
              r = r * (bound - origin) + origin;
              if (r >= bound) // correct for rounding
                  r = Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
          }
          return r;
      }
  
      /**
       * Returns the next pseudorandom, uniformly distributed {@code int}
       * value from this random number generator's sequence. The general
       * contract of {@code nextInt} is that one {@code int} value is
       * pseudorandomly generated and returned. All 2<sup>32</sup> possible
       * {@code int} values are produced with (approximately) equal probability.
       *
       * <p>The method {@code nextInt} is implemented by class {@code Random}
       * as if by:
       *  <pre> {@code
       * public int nextInt() {
       *   return next(32);
       * }}</pre>
       *
       * @return the next pseudorandom, uniformly distributed {@code int}
       *         value from this random number generator's sequence
       */
      public int nextInt() {
          return next(32);
      }
  
      /**
       * Returns a pseudorandom, uniformly distributed {@code int} value
       * between 0 (inclusive) and the specified value (exclusive), drawn from
       * this random number generator's sequence.  The general contract of
       * {@code nextInt} is that one {@code int} value in the specified range
       * is pseudorandomly generated and returned.  All {@code bound} possible
       * {@code int} values are produced with (approximately) equal
       * probability.  The method {@code nextInt(int bound)} is implemented by
       * class {@code Random} as if by:
       *  <pre> {@code
       * public int nextInt(int bound) {
       *   if (bound <= 0)
       *     throw new IllegalArgumentException("bound must be positive");
       *
       *   if ((bound & -bound) == bound)  // i.e., bound is a power of 2
       *     return (int)((bound * (long)next(31)) >> 31);
       *
       *   int bits, val;
       *   do {
       *       bits = next(31);
       *       val = bits % bound;
       *   } while (bits - val + (bound-1) < 0);
       *   return val;
       * }}</pre>
       *
       * <p>The hedge "approximately" is used in the foregoing description only
       * because the next method is only approximately an unbiased source of
       * independently chosen bits.  If it were a perfect source of randomly
       * chosen bits, then the algorithm shown would choose {@code int}
       * values from the stated range with perfect uniformity.
       * <p>
       * The algorithm is slightly tricky.  It rejects values that would result
       * in an uneven distribution (due to the fact that 2^31 is not divisible
       * by n). The probability of a value being rejected depends on n.  The
       * worst case is n=2^30+1, for which the probability of a reject is 1/2,
       * and the expected number of iterations before the loop terminates is 2.
       * <p>
       * The algorithm treats the case where n is a power of two specially: it
       * returns the correct number of high-order bits from the underlying
       * pseudo-random number generator.  In the absence of special treatment,
       * the correct number of <i>low-order</i> bits would be returned.  Linear
       * congruential pseudo-random number generators such as the one
       * implemented by this class are known to have short periods in the
       * sequence of values of their low-order bits.  Thus, this special case
       * greatly increases the length of the sequence of values returned by
       * successive calls to this method if n is a small power of two.
       *
       * @param bound the upper bound (exclusive).  Must be positive.
       * @return the next pseudorandom, uniformly distributed {@code int}
       *         value between zero (inclusive) and {@code bound} (exclusive)
       *         from this random number generator's sequence
       * @throws IllegalArgumentException if bound is not positive
       * @since 1.2
       */
      public int nextInt(int bound) {
          if (bound <= 0)
              throw new IllegalArgumentException(BadBound);
  
          int r = next(31);
          int m = bound - 1;
          if ((bound & m) == 0)  // i.e., bound is a power of 2
              r = (int)((bound * (long)r) >> 31);
          else {
              for (int u = r;
                   u - (r = u % bound) + m < 0;
                   u = next(31))
                  ;
          }
          return r;
      }
  
      /**
       * Returns the next pseudorandom, uniformly distributed {@code long}
       * value from this random number generator's sequence. The general
       * contract of {@code nextLong} is that one {@code long} value is
       * pseudorandomly generated and returned.
       *
       * <p>The method {@code nextLong} is implemented by class {@code Random}
       * as if by:
       *  <pre> {@code
       * public long nextLong() {
       *   return ((long)next(32) << 32) + next(32);
       * }}</pre>
       *
       * Because class {@code Random} uses a seed with only 48 bits,
       * this algorithm will not return all possible {@code long} values.
       *
       * @return the next pseudorandom, uniformly distributed {@code long}
       *         value from this random number generator's sequence
       */
      public long nextLong() {
          // it's okay that the bottom word remains signed.
          return ((long)(next(32)) << 32) + next(32);
      }
  
      /**
       * Returns the next pseudorandom, uniformly distributed
       * {@code boolean} value from this random number generator's
       * sequence. The general contract of {@code nextBoolean} is that one
       * {@code boolean} value is pseudorandomly generated and returned.  The
       * values {@code true} and {@code false} are produced with
       * (approximately) equal probability.
       *
       * <p>The method {@code nextBoolean} is implemented by class {@code Random}
       * as if by:
       *  <pre> {@code
       * public boolean nextBoolean() {
       *   return next(1) != 0;
       * }}</pre>
       *
       * @return the next pseudorandom, uniformly distributed
       *         {@code boolean} value from this random number generator's
       *         sequence
       * @since 1.2
       */
      public boolean nextBoolean() {
          return next(1) != 0;
      }
  
      /**
       * Returns the next pseudorandom, uniformly distributed {@code float}
       * value between {@code 0.0} and {@code 1.0} from this random
       * number generator's sequence.
       *
       * <p>The general contract of {@code nextFloat} is that one
       * {@code float} value, chosen (approximately) uniformly from the
       * range {@code 0.0f} (inclusive) to {@code 1.0f} (exclusive), is
       * pseudorandomly generated and returned. All 2<sup>24</sup> possible
       * {@code float} values of the form <i>m&nbsp;x&nbsp;</i>2<sup>-24</sup>,
       * where <i>m</i> is a positive integer less than 2<sup>24</sup>, are
       * produced with (approximately) equal probability.
       *
       * <p>The method {@code nextFloat} is implemented by class {@code Random}
       * as if by:
       *  <pre> {@code
       * public float nextFloat() {
       *   return next(24) / ((float)(1 << 24));
       * }}</pre>
       *
       * <p>The hedge "approximately" is used in the foregoing description only
       * because the next method is only approximately an unbiased source of
       * independently chosen bits. If it were a perfect source of randomly
       * chosen bits, then the algorithm shown would choose {@code float}
       * values from the stated range with perfect uniformity.<p>
       * [In early versions of Java, the result was incorrectly calculated as:
       *  <pre> {@code
       *   return next(30) / ((float)(1 << 30));}</pre>
       * This might seem to be equivalent, if not better, but in fact it
       * introduced a slight nonuniformity because of the bias in the rounding
       * of floating-point numbers: it was slightly more likely that the
       * low-order bit of the significand would be 0 than that it would be 1.]
       *
       * @return the next pseudorandom, uniformly distributed {@code float}
       *         value between {@code 0.0} and {@code 1.0} from this
       *         random number generator's sequence
       */
      public float nextFloat() {
          return next(24) / ((float)(1 << 24));
      }
  
      /**
       * Returns the next pseudorandom, uniformly distributed
       * {@code double} value between {@code 0.0} and
       * {@code 1.0} from this random number generator's sequence.
       *
       * <p>The general contract of {@code nextDouble} is that one
       * {@code double} value, chosen (approximately) uniformly from the
       * range {@code 0.0d} (inclusive) to {@code 1.0d} (exclusive), is
       * pseudorandomly generated and returned.
       *
       * <p>The method {@code nextDouble} is implemented by class {@code Random}
       * as if by:
       *  <pre> {@code
       * public double nextDouble() {
       *   return (((long)next(26) << 27) + next(27))
       *     / (double)(1L << 53);
       * }}</pre>
       *
       * <p>The hedge "approximately" is used in the foregoing description only
       * because the {@code next} method is only approximately an unbiased
       * source of independently chosen bits. If it were a perfect source of
       * randomly chosen bits, then the algorithm shown would choose
       * {@code double} values from the stated range with perfect uniformity.
       * <p>[In early versions of Java, the result was incorrectly calculated as:
       *  <pre> {@code
       *   return (((long)next(27) << 27) + next(27))
       *     / (double)(1L << 54);}</pre>
       * This might seem to be equivalent, if not better, but in fact it
       * introduced a large nonuniformity because of the bias in the rounding
       * of floating-point numbers: it was three times as likely that the
       * low-order bit of the significand would be 0 than that it would be 1!
       * This nonuniformity probably doesn't matter much in practice, but we
       * strive for perfection.]
       *
       * @return the next pseudorandom, uniformly distributed {@code double}
       *         value between {@code 0.0} and {@code 1.0} from this
       *         random number generator's sequence
       * @see Math#random
       */
      public double nextDouble() {
          return (((long)(next(26)) << 27) + next(27)) * DOUBLE_UNIT;
      }
  
      private double nextNextGaussian;
      private boolean haveNextNextGaussian = false;
  
      /**
       * Returns the next pseudorandom, Gaussian ("normally") distributed
       * {@code double} value with mean {@code 0.0} and standard
       * deviation {@code 1.0} from this random number generator's sequence.
       * <p>
       * The general contract of {@code nextGaussian} is that one
       * {@code double} value, chosen from (approximately) the usual
       * normal distribution with mean {@code 0.0} and standard deviation
       * {@code 1.0}, is pseudorandomly generated and returned.
       *
       * <p>The method {@code nextGaussian} is implemented by class
       * {@code Random} as if by a threadsafe version of the following:
       *  <pre> {@code
       * private double nextNextGaussian;
       * private boolean haveNextNextGaussian = false;
       *
       * public double nextGaussian() {
       *   if (haveNextNextGaussian) {
       *     haveNextNextGaussian = false;
       *     return nextNextGaussian;
       *   } else {
       *     double v1, v2, s;
       *     do {
       *       v1 = 2 * nextDouble() - 1;   // between -1.0 and 1.0
       *       v2 = 2 * nextDouble() - 1;   // between -1.0 and 1.0
       *       s = v1 * v1 + v2 * v2;
       *     } while (s >= 1 || s == 0);
       *     double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s)/s);
       *     nextNextGaussian = v2 * multiplier;
       *     haveNextNextGaussian = true;
       *     return v1 * multiplier;
       *   }
       * }}</pre>
       * This uses the <i>polar method</i> of G. E. P. Box, M. E. Muller, and
       * G. Marsaglia, as described by Donald E. Knuth in <i>The Art of
       * Computer Programming</i>, Volume 3: <i>Seminumerical Algorithms</i>,
       * section 3.4.1, subsection C, algorithm P. Note that it generates two
       * independent values at the cost of only one call to {@code StrictMath.log}
       * and one call to {@code StrictMath.sqrt}.
       *
       * @return the next pseudorandom, Gaussian ("normally") distributed
       *         {@code double} value with mean {@code 0.0} and
       *         standard deviation {@code 1.0} from this random number
       *         generator's sequence
       */
      synchronized public double nextGaussian() {
          // See Knuth, ACP, Section 3.4.1 Algorithm C.
          if (haveNextNextGaussian) {
              haveNextNextGaussian = false;
              return nextNextGaussian;
          } else {
              double v1, v2, s;
              do {
                  v1 = 2 * nextDouble() - 1; // between -1 and 1
                  v2 = 2 * nextDouble() - 1; // between -1 and 1
                  s = v1 * v1 + v2 * v2;
              } while (s >= 1 || s == 0);
              double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s)/s);
              nextNextGaussian = v2 * multiplier;
              haveNextNextGaussian = true;
              return v1 * multiplier;
          }
      }
  
      // stream methods, coded in a way intended to better isolate for
      // maintenance purposes the small differences across forms.
  
      /**
       * Returns a stream producing the given {@code streamSize} number of
       * pseudorandom {@code int} values.
       *
       * <p>A pseudorandom {@code int} value is generated as if it's the result of
       * calling the method {@link #nextInt()}.
       *
       * @param streamSize the number of values to generate
       * @return a stream of pseudorandom {@code int} values
       * @throws IllegalArgumentException if {@code streamSize} is
       *         less than zero
       * @since 1.8
       */
      public IntStream ints(long streamSize) {
          if (streamSize < 0L)
              throw new IllegalArgumentException(BadSize);
          return StreamSupport.intStream
                  (new RandomIntsSpliterator
                           (this, 0L, streamSize, Integer.MAX_VALUE, 0),
                   false);
      }
  
      /**
       * Returns an effectively unlimited stream of pseudorandom {@code int}
       * values.
       *
       * <p>A pseudorandom {@code int} value is generated as if it's the result of
       * calling the method {@link #nextInt()}.
       *
       * @implNote This method is implemented to be equivalent to {@code
       * ints(Long.MAX_VALUE)}.
       *
       * @return a stream of pseudorandom {@code int} values
       * @since 1.8
       */
      public IntStream ints() {
          return StreamSupport.intStream
                  (new RandomIntsSpliterator
                           (this, 0L, Long.MAX_VALUE, Integer.MAX_VALUE, 0),
                   false);
      }
  
      /**
       * Returns a stream producing the given {@code streamSize} number
       * of pseudorandom {@code int} values, each conforming to the given
       * origin (inclusive) and bound (exclusive).
       *
       * <p>A pseudorandom {@code int} value is generated as if it's the result of
       * calling the following method with the origin and bound:
       * <pre> {@code
       * int nextInt(int origin, int bound) {
       *   int n = bound - origin;
       *   if (n > 0) {
       *     return nextInt(n) + origin;
       *   }
       *   else {  // range not representable as int
       *     int r;
       *     do {
       *       r = nextInt();
       *     } while (r < origin || r >= bound);
       *     return r;
       *   }
       * }}</pre>
       *
       * @param streamSize the number of values to generate
       * @param randomNumberOrigin the origin (inclusive) of each random value
       * @param randomNumberBound the bound (exclusive) of each random value
       * @return a stream of pseudorandom {@code int} values,
       *         each with the given origin (inclusive) and bound (exclusive)
       * @throws IllegalArgumentException if {@code streamSize} is
       *         less than zero, or {@code randomNumberOrigin}
       *         is greater than or equal to {@code randomNumberBound}
       * @since 1.8
       */
      public IntStream ints(long streamSize, int randomNumberOrigin,
                            int randomNumberBound) {
          if (streamSize < 0L)
              throw new IllegalArgumentException(BadSize);
          if (randomNumberOrigin >= randomNumberBound)
              throw new IllegalArgumentException(BadRange);
          return StreamSupport.intStream
                  (new RandomIntsSpliterator
                           (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
                   false);
      }
  
      /**
       * Returns an effectively unlimited stream of pseudorandom {@code
       * int} values, each conforming to the given origin (inclusive) and bound
       * (exclusive).
       *
       * <p>A pseudorandom {@code int} value is generated as if it's the result of
       * calling the following method with the origin and bound:
       * <pre> {@code
       * int nextInt(int origin, int bound) {
       *   int n = bound - origin;
       *   if (n > 0) {
       *     return nextInt(n) + origin;
       *   }
       *   else {  // range not representable as int
       *     int r;
       *     do {
       *       r = nextInt();
       *     } while (r < origin || r >= bound);
       *     return r;
       *   }
       * }}</pre>
       *
       * @implNote This method is implemented to be equivalent to {@code
       * ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
       *
       * @param randomNumberOrigin the origin (inclusive) of each random value
       * @param randomNumberBound the bound (exclusive) of each random value
       * @return a stream of pseudorandom {@code int} values,
       *         each with the given origin (inclusive) and bound (exclusive)
       * @throws IllegalArgumentException if {@code randomNumberOrigin}
       *         is greater than or equal to {@code randomNumberBound}
       * @since 1.8
       */
      public IntStream ints(int randomNumberOrigin, int randomNumberBound) {
          if (randomNumberOrigin >= randomNumberBound)
              throw new IllegalArgumentException(BadRange);
          return StreamSupport.intStream
                  (new RandomIntsSpliterator
                           (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
                   false);
      }
  
      /**
       * Returns a stream producing the given {@code streamSize} number of
       * pseudorandom {@code long} values.
       *
       * <p>A pseudorandom {@code long} value is generated as if it's the result
       * of calling the method {@link #nextLong()}.
       *
       * @param streamSize the number of values to generate
       * @return a stream of pseudorandom {@code long} values
       * @throws IllegalArgumentException if {@code streamSize} is
       *         less than zero
       * @since 1.8
       */
      public LongStream longs(long streamSize) {
          if (streamSize < 0L)
              throw new IllegalArgumentException(BadSize);
          return StreamSupport.longStream
                  (new RandomLongsSpliterator
                           (this, 0L, streamSize, Long.MAX_VALUE, 0L),
                   false);
      }
  
      /**
       * Returns an effectively unlimited stream of pseudorandom {@code long}
       * values.
       *
       * <p>A pseudorandom {@code long} value is generated as if it's the result
       * of calling the method {@link #nextLong()}.
       *
       * @implNote This method is implemented to be equivalent to {@code
       * longs(Long.MAX_VALUE)}.
       *
       * @return a stream of pseudorandom {@code long} values
       * @since 1.8
       */
      public LongStream longs() {
          return StreamSupport.longStream
                  (new RandomLongsSpliterator
                           (this, 0L, Long.MAX_VALUE, Long.MAX_VALUE, 0L),
                   false);
      }
  
      /**
       * Returns a stream producing the given {@code streamSize} number of
       * pseudorandom {@code long}, each conforming to the given origin
       * (inclusive) and bound (exclusive).
       *
       * <p>A pseudorandom {@code long} value is generated as if it's the result
       * of calling the following method with the origin and bound:
       * <pre> {@code
       * long nextLong(long origin, long bound) {
       *   long r = nextLong();
       *   long n = bound - origin, m = n - 1;
       *   if ((n & m) == 0L)  // power of two
       *     r = (r & m) + origin;
       *   else if (n > 0L) {  // reject over-represented candidates
       *     for (long u = r >>> 1;            // ensure nonnegative
       *          u + m - (r = u % n) < 0L;    // rejection check
       *          u = nextLong() >>> 1) // retry
       *         ;
       *     r += origin;
       *   }
       *   else {              // range not representable as long
       *     while (r < origin || r >= bound)
       *       r = nextLong();
       *   }
       *   return r;
       * }}</pre>
       *
       * @param streamSize the number of values to generate
       * @param randomNumberOrigin the origin (inclusive) of each random value
       * @param randomNumberBound the bound (exclusive) of each random value
       * @return a stream of pseudorandom {@code long} values,
       *         each with the given origin (inclusive) and bound (exclusive)
       * @throws IllegalArgumentException if {@code streamSize} is
       *         less than zero, or {@code randomNumberOrigin}
       *         is greater than or equal to {@code randomNumberBound}
       * @since 1.8
       */
      public LongStream longs(long streamSize, long randomNumberOrigin,
                              long randomNumberBound) {
          if (streamSize < 0L)
              throw new IllegalArgumentException(BadSize);
          if (randomNumberOrigin >= randomNumberBound)
              throw new IllegalArgumentException(BadRange);
          return StreamSupport.longStream
                  (new RandomLongsSpliterator
                           (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
                   false);
      }
  
      /**
       * Returns an effectively unlimited stream of pseudorandom {@code
       * long} values, each conforming to the given origin (inclusive) and bound
       * (exclusive).
       *
       * <p>A pseudorandom {@code long} value is generated as if it's the result
       * of calling the following method with the origin and bound:
       * <pre> {@code
       * long nextLong(long origin, long bound) {
       *   long r = nextLong();
       *   long n = bound - origin, m = n - 1;
       *   if ((n & m) == 0L)  // power of two
       *     r = (r & m) + origin;
       *   else if (n > 0L) {  // reject over-represented candidates
       *     for (long u = r >>> 1;            // ensure nonnegative
       *          u + m - (r = u % n) < 0L;    // rejection check
       *          u = nextLong() >>> 1) // retry
       *         ;
       *     r += origin;
       *   }
       *   else {              // range not representable as long
       *     while (r < origin || r >= bound)
       *       r = nextLong();
       *   }
       *   return r;
       * }}</pre>
       *
       * @implNote This method is implemented to be equivalent to {@code
       * longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
       *
       * @param randomNumberOrigin the origin (inclusive) of each random value
       * @param randomNumberBound the bound (exclusive) of each random value
       * @return a stream of pseudorandom {@code long} values,
       *         each with the given origin (inclusive) and bound (exclusive)
       * @throws IllegalArgumentException if {@code randomNumberOrigin}
       *         is greater than or equal to {@code randomNumberBound}
       * @since 1.8
       */
      public LongStream longs(long randomNumberOrigin, long randomNumberBound) {
          if (randomNumberOrigin >= randomNumberBound)
              throw new IllegalArgumentException(BadRange);
          return StreamSupport.longStream
                  (new RandomLongsSpliterator
                           (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
                   false);
      }
  
      /**
       * Returns a stream producing the given {@code streamSize} number of
       * pseudorandom {@code double} values, each between zero
       * (inclusive) and one (exclusive).
       *
       * <p>A pseudorandom {@code double} value is generated as if it's the result
       * of calling the method {@link #nextDouble()}.
       *
       * @param streamSize the number of values to generate
       * @return a stream of {@code double} values
       * @throws IllegalArgumentException if {@code streamSize} is
       *         less than zero
       * @since 1.8
       */
      public DoubleStream doubles(long streamSize) {
          if (streamSize < 0L)
              throw new IllegalArgumentException(BadSize);
          return StreamSupport.doubleStream
                  (new RandomDoublesSpliterator
                           (this, 0L, streamSize, Double.MAX_VALUE, 0.0),
                   false);
      }
  
      /**
       * Returns an effectively unlimited stream of pseudorandom {@code
       * double} values, each between zero (inclusive) and one
       * (exclusive).
       *
       * <p>A pseudorandom {@code double} value is generated as if it's the result
       * of calling the method {@link #nextDouble()}.
       *
       * @implNote This method is implemented to be equivalent to {@code
       * doubles(Long.MAX_VALUE)}.
       *
       * @return a stream of pseudorandom {@code double} values
       * @since 1.8
       */
      public DoubleStream doubles() {
          return StreamSupport.doubleStream
                  (new RandomDoublesSpliterator
                           (this, 0L, Long.MAX_VALUE, Double.MAX_VALUE, 0.0),
                   false);
      }
  
      /**
       * Returns a stream producing the given {@code streamSize} number of
       * pseudorandom {@code double} values, each conforming to the given origin
       * (inclusive) and bound (exclusive).
       *
       * <p>A pseudorandom {@code double} value is generated as if it's the result
       * of calling the following method with the origin and bound:
       * <pre> {@code
       * double nextDouble(double origin, double bound) {
       *   double r = nextDouble();
       *   r = r * (bound - origin) + origin;
       *   if (r >= bound) // correct for rounding
       *     r = Math.nextDown(bound);
       *   return r;
       * }}</pre>
       *
       * @param streamSize the number of values to generate
       * @param randomNumberOrigin the origin (inclusive) of each random value
       * @param randomNumberBound the bound (exclusive) of each random value
       * @return a stream of pseudorandom {@code double} values,
       *         each with the given origin (inclusive) and bound (exclusive)
       * @throws IllegalArgumentException if {@code streamSize} is
       *         less than zero
       * @throws IllegalArgumentException if {@code randomNumberOrigin}
       *         is greater than or equal to {@code randomNumberBound}
       * @since 1.8
       */
      public DoubleStream doubles(long streamSize, double randomNumberOrigin,
                                  double randomNumberBound) {
          if (streamSize < 0L)
              throw new IllegalArgumentException(BadSize);
          if (!(randomNumberOrigin < randomNumberBound))
              throw new IllegalArgumentException(BadRange);
          return StreamSupport.doubleStream
                  (new RandomDoublesSpliterator
                           (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
                   false);
      }
  
      /**
       * Returns an effectively unlimited stream of pseudorandom {@code
       * double} values, each conforming to the given origin (inclusive) and bound
       * (exclusive).
       *
       * <p>A pseudorandom {@code double} value is generated as if it's the result
       * of calling the following method with the origin and bound:
       * <pre> {@code
       * double nextDouble(double origin, double bound) {
       *   double r = nextDouble();
       *   r = r * (bound - origin) + origin;
       *   if (r >= bound) // correct for rounding
       *     r = Math.nextDown(bound);
       *   return r;
       * }}</pre>
       *
       * @implNote This method is implemented to be equivalent to {@code
       * doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
       *
       * @param randomNumberOrigin the origin (inclusive) of each random value
       * @param randomNumberBound the bound (exclusive) of each random value
       * @return a stream of pseudorandom {@code double} values,
       *         each with the given origin (inclusive) and bound (exclusive)
       * @throws IllegalArgumentException if {@code randomNumberOrigin}
       *         is greater than or equal to {@code randomNumberBound}
       * @since 1.8
       */
      public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
          if (!(randomNumberOrigin < randomNumberBound))
              throw new IllegalArgumentException(BadRange);
          return StreamSupport.doubleStream
                  (new RandomDoublesSpliterator
                           (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
                   false);
      }
  
      /**
       * Spliterator for int streams.  We multiplex the four int
       * versions into one class by treating a bound less than origin as
       * unbounded, and also by treating "infinite" as equivalent to
       * Long.MAX_VALUE. For splits, it uses the standard divide-by-two
       * approach. The long and double versions of this class are
       * identical except for types.
       */
      static final class RandomIntsSpliterator implements Spliterator.OfInt {
          final Random rng;
          long index;
          final long fence;
          final int origin;
          final int bound;
          RandomIntsSpliterator(Random rng, long index, long fence,
                                int origin, int bound) {
              this.rng = rng; this.index = index; this.fence = fence;
              this.origin = origin; this.bound = bound;
          }
  
          public RandomIntsSpliterator trySplit() {
              long i = index, m = (i + fence) >>> 1;
              return (m <= i) ? null :
                     new RandomIntsSpliterator(rng, i, index = m, origin, bound);
          }
  
          public long estimateSize() {
              return fence - index;
          }
  
          public int characteristics() {
              return (Spliterator.SIZED | Spliterator.SUBSIZED |
                      Spliterator.NONNULL | Spliterator.IMMUTABLE);
          }
  
          public boolean tryAdvance(IntConsumer consumer) {
              if (consumer == null) throw new NullPointerException();
              long i = index, f = fence;
              if (i < f) {
                  consumer.accept(rng.internalNextInt(origin, bound));
                  index = i + 1;
                  return true;
              }
              return false;
          }
  
          public void forEachRemaining(IntConsumer consumer) {
              if (consumer == null) throw new NullPointerException();
              long i = index, f = fence;
              if (i < f) {
                  index = f;
                  Random r = rng;
                  int o = origin, b = bound;
                  do {
                      consumer.accept(r.internalNextInt(o, b));
                  } while (++i < f);
              }
          }
      }
  
      /**
       * Spliterator for long streams.
       */
      static final class RandomLongsSpliterator implements Spliterator.OfLong {
          final Random rng;
          long index;
          final long fence;
          final long origin;
          final long bound;
          RandomLongsSpliterator(Random rng, long index, long fence,
                                 long origin, long bound) {
              this.rng = rng; this.index = index; this.fence = fence;
              this.origin = origin; this.bound = bound;
          }
  
          public RandomLongsSpliterator trySplit() {
              long i = index, m = (i + fence) >>> 1;
              return (m <= i) ? null :
                     new RandomLongsSpliterator(rng, i, index = m, origin, bound);
          }
  
          public long estimateSize() {
              return fence - index;
          }
  
          public int characteristics() {
              return (Spliterator.SIZED | Spliterator.SUBSIZED |
                      Spliterator.NONNULL | Spliterator.IMMUTABLE);
          }
  
          public boolean tryAdvance(LongConsumer consumer) {
              if (consumer == null) throw new NullPointerException();
              long i = index, f = fence;
              if (i < f) {
                  consumer.accept(rng.internalNextLong(origin, bound));
                  index = i + 1;
                  return true;
              }
              return false;
          }
  
          public void forEachRemaining(LongConsumer consumer) {
              if (consumer == null) throw new NullPointerException();
              long i = index, f = fence;
              if (i < f) {
                  index = f;
                  Random r = rng;
                  long o = origin, b = bound;
                  do {
                      consumer.accept(r.internalNextLong(o, b));
                  } while (++i < f);
              }
          }
  
      }
  
      /**
       * Spliterator for double streams.
       */
      static final class RandomDoublesSpliterator implements Spliterator.OfDouble {
          final Random rng;
          long index;
          final long fence;
          final double origin;
          final double bound;
          RandomDoublesSpliterator(Random rng, long index, long fence,
                                   double origin, double bound) {
              this.rng = rng; this.index = index; this.fence = fence;
              this.origin = origin; this.bound = bound;
          }
  
          public RandomDoublesSpliterator trySplit() {
              long i = index, m = (i + fence) >>> 1;
              return (m <= i) ? null :
                     new RandomDoublesSpliterator(rng, i, index = m, origin, bound);
          }
  
          public long estimateSize() {
              return fence - index;
          }
  
          public int characteristics() {
              return (Spliterator.SIZED | Spliterator.SUBSIZED |
                      Spliterator.NONNULL | Spliterator.IMMUTABLE);
          }
  
          public boolean tryAdvance(DoubleConsumer consumer) {
              if (consumer == null) throw new NullPointerException();
              long i = index, f = fence;
              if (i < f) {
                  consumer.accept(rng.internalNextDouble(origin, bound));
                  index = i + 1;
                  return true;
              }
              return false;
          }
  
          public void forEachRemaining(DoubleConsumer consumer) {
              if (consumer == null) throw new NullPointerException();
              long i = index, f = fence;
              if (i < f) {
                  index = f;
                  Random r = rng;
                  double o = origin, b = bound;
                  do {
                      consumer.accept(r.internalNextDouble(o, b));
                  } while (++i < f);
              }
          }
      }
  
      /**
       * Serializable fields for Random.
       *
       * @serialField    seed long
       *              seed for random computations
       * @serialField    nextNextGaussian double
       *              next Gaussian to be returned
       * @serialField      haveNextNextGaussian boolean
       *              nextNextGaussian is valid
       */
      private static final ObjectStreamField[] serialPersistentFields = {
          new ObjectStreamField("seed", Long.TYPE),
          new ObjectStreamField("nextNextGaussian", Double.TYPE),
          new ObjectStreamField("haveNextNextGaussian", Boolean.TYPE)
      };
  
      /**
       * Reconstitute the {@code Random} instance from a stream (that is,
       * deserialize it).
       */
      private void readObject(ObjectInputStream s)
          throws IOException, ClassNotFoundException {
  
          ObjectInputStream.GetField fields = s.readFields();
  
          // The seed is read in as {@code long} for
          // historical reasons, but it is converted to an AtomicLong.
          long seedVal = fields.get("seed", -1L);
          if (seedVal < 0)
            throw new StreamCorruptedException(
                                "Random: invalid seed");
          resetSeed(seedVal);
          nextNextGaussian = fields.get("nextNextGaussian", 0.0);
          haveNextNextGaussian = fields.get("haveNextNextGaussian", false);
      }
  
      /**
       * Save the {@code Random} instance to a stream.
       */
      synchronized private void writeObject(ObjectOutputStream s)
          throws IOException {
  
          // set the values of the Serializable fields
          ObjectOutputStream.PutField fields = s.putFields();
  
          // The seed is serialized as a long for historical reasons.
          fields.put("seed", seed.get());
          fields.put("nextNextGaussian", nextNextGaussian);
          fields.put("haveNextNextGaussian", haveNextNextGaussian);
  
          // save them
          s.writeFields();
      }
  
      // Support for resetting seed while deserializing
      private static final Unsafe unsafe = Unsafe.getUnsafe();
      private static final long seedOffset;
      static {
          try {
              seedOffset = unsafe.objectFieldOffset
                  (Random.class.getDeclaredField("seed"));
          } catch (Exception ex) { throw new Error(ex); }
      }
      private void resetSeed(long seedVal) {
          unsafe.putObjectVolatile(this, seedOffset, new AtomicLong(seedVal));
      }
  }
  