https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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package java.util;

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;


A generator of uniform pseudorandom values applicable for use in (among other contexts) isolated parallel computations that may generate subtasks. Class SplittableRandom supports methods for producing pseudorandom numbers of type int, long, and double with similar usages as for class Random but differs in the following ways: 
    

  • Series of generated values pass the DieHarder suite testing
independence and uniformity properties of random number generators.
(Most recently validated with  version
3.31.1.) These tests validate only the methods for certain
types and ranges, but similar properties are expected to hold, at
least approximately, for others as well. The period
(length of any series of generated values before it repeats) is at
least 264.

  • Method split constructs and returns a new SplittableRandom instance that shares no mutable state with the current instance. However, with very high probability, the values collectively generated by the two objects have the same statistical properties as if the same quantity of values were generated by a single thread using a single 
SplittableRandom object. 
  • Instances of SplittableRandom are not thread-safe. They are designed to be split, not shared, across threads. For example, a 
fork/join-style computation using random numbers might include a construction of the form new
Subtask(aSplittableRandom.split()).fork(). 
  • This class provides additional methods for generating random streams, that employ the above techniques when used in 
stream.parallel() mode. 


Instances of SplittableRandom are not cryptographically secure. Consider instead using SecureRandom in security-sensitive applications. Additionally, default-constructed instances do not use a cryptographically random seed unless the system property java.util.secureRandomSeed is set to true. 
Author: Guy Steele,  Doug Lea
Since:  1.8
/**
 * A generator of uniform pseudorandom values applicable for use in
 * (among other contexts) isolated parallel computations that may
 * generate subtasks. Class {@code SplittableRandom} supports methods for
 * producing pseudorandom numbers of type {@code int}, {@code long},
 * and {@code double} with similar usages as for class
 * {@link java.util.Random} but differs in the following ways:
 *
 * <ul>
 *
 * <li>Series of generated values pass the DieHarder suite testing
 * independence and uniformity properties of random number generators.
 * (Most recently validated with <a
 * href="http://www.phy.duke.edu/~rgb/General/dieharder.php"> version
 * 3.31.1</a>.) These tests validate only the methods for certain
 * types and ranges, but similar properties are expected to hold, at
 * least approximately, for others as well. The <em>period</em>
 * (length of any series of generated values before it repeats) is at
 * least 2<sup>64</sup>.
 *
 * <li>Method {@link #split} constructs and returns a new
 * SplittableRandom instance that shares no mutable state with the
 * current instance. However, with very high probability, the
 * values collectively generated by the two objects have the same
 * statistical properties as if the same quantity of values were
 * generated by a single thread using a single {@code
 * SplittableRandom} object.
 *
 * <li>Instances of SplittableRandom are <em>not</em> thread-safe.
 * They are designed to be split, not shared, across threads. For
 * example, a {@link java.util.concurrent.ForkJoinTask
 * fork/join-style} computation using random numbers might include a
 * construction of the form {@code new
 * Subtask(aSplittableRandom.split()).fork()}.
 *
 * <li>This class provides additional methods for generating random
 * streams, that employ the above techniques when used in {@code
 * stream.parallel()} mode.
 *
 * </ul>
 *
 * <p>Instances of {@code SplittableRandom} are not cryptographically
 * secure.  Consider instead using {@link java.security.SecureRandom}
 * in security-sensitive applications. Additionally,
 * default-constructed instances do not use a cryptographically random
 * seed unless the {@linkplain System#getProperty system property}
 * {@code java.util.secureRandomSeed} is set to {@code true}.
 *
 * @author  Guy Steele
 * @author  Doug Lea
 * @since   1.8
 */
public final class SplittableRandom {

    /*
     * Implementation Overview.
     *
     * This algorithm was inspired by the "DotMix" algorithm by
     * Leiserson, Schardl, and Sukha "Deterministic Parallel
     * Random-Number Generation for Dynamic-Multithreading Platforms",
     * PPoPP 2012, as well as those in "Parallel random numbers: as
     * easy as 1, 2, 3" by Salmon, Morae, Dror, and Shaw, SC 2011.  It
     * differs mainly in simplifying and cheapening operations.
     *
     * The primary update step (method nextSeed()) is to add a
     * constant ("gamma") to the current (64 bit) seed, forming a
     * simple sequence.  The seed and the gamma values for any two
     * SplittableRandom instances are highly likely to be different.
     *
     * Methods nextLong, nextInt, and derivatives do not return the
     * sequence (seed) values, but instead a hash-like bit-mix of
     * their bits, producing more independently distributed sequences.
     * For nextLong, the mix64 function is based on David Stafford's
     * (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html)
     * "Mix13" variant of the "64-bit finalizer" function in Austin
     * Appleby's MurmurHash3 algorithm (see
     * http://code.google.com/p/smhasher/wiki/MurmurHash3). The mix32
     * function is based on Stafford's Mix04 mix function, but returns
     * the upper 32 bits cast as int.
     *
     * The split operation uses the current generator to form the seed
     * and gamma for another SplittableRandom.  To conservatively
     * avoid potential correlations between seed and value generation,
     * gamma selection (method mixGamma) uses different
     * (Murmurhash3's) mix constants.  To avoid potential weaknesses
     * in bit-mixing transformations, we restrict gammas to odd values
     * with at least 24 0-1 or 1-0 bit transitions.  Rather than
     * rejecting candidates with too few or too many bits set, method
     * mixGamma flips some bits (which has the effect of mapping at
     * most 4 to any given gamma value).  This reduces the effective
     * set of 64bit odd gamma values by about 2%, and serves as an
     * automated screening for sequence constant selection that is
     * left as an empirical decision in some other hashing and crypto
     * algorithms.
     *
     * The resulting generator thus transforms a sequence in which
     * (typically) many bits change on each step, with an inexpensive
     * mixer with good (but less than cryptographically secure)
     * avalanching.
     *
     * The default (no-argument) constructor, in essence, invokes
     * split() for a common "defaultGen" SplittableRandom.  Unlike
     * other cases, this split must be performed in a thread-safe
     * manner, so we use an AtomicLong to represent the seed rather
     * than use an explicit SplittableRandom. To bootstrap the
     * defaultGen, we start off using a seed based on current time
     * unless the java.util.secureRandomSeed property is set. This
     * serves as a slimmed-down (and insecure) variant of SecureRandom
     * that also avoids stalls that may occur when using /dev/random.
     *
     * It is a relatively simple matter to apply the basic design here
     * to use 128 bit seeds. However, emulating 128bit arithmetic and
     * carrying around twice the state add more overhead than appears
     * warranted for current usages.
     *
     * File organization: First the non-public methods that constitute
     * the main algorithm, then the main public methods, followed by
     * some custom spliterator classes needed for stream methods.
     */

    
The golden ratio scaled to 64bits, used as the initial gamma
value for (unsplit) SplittableRandoms.

/**
     * The golden ratio scaled to 64bits, used as the initial gamma
     * value for (unsplit) SplittableRandoms.
     */
    private static final long GOLDEN_GAMMA = 0x9e3779b97f4a7c15L;

    
The least non-zero value returned by nextDouble(). This value
is scaled by a random value of 53 bits to produce a result.

/**
     * The least non-zero value returned by nextDouble(). This value
     * is scaled by a random value of 53 bits to produce a result.
     */
    private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53);

    
The seed. Updated only via method nextSeed.

/**
     * The seed. Updated only via method nextSeed.
     */
    private long seed;

    
The step value.

/**
     * The step value.
     */
    private final long gamma;

    
Internal constructor used by all others except default constructor.

/**
     * Internal constructor used by all others except default constructor.
     */
    private SplittableRandom(long seed, long gamma) {
        this.seed = seed;
        this.gamma = gamma;
    }

    
Computes Stafford variant 13 of 64bit mix function.

/**
     * Computes Stafford variant 13 of 64bit mix function.
     */
    private static long mix64(long z) {
        z = (z ^ (z >>> 30)) * 0xbf58476d1ce4e5b9L;
        z = (z ^ (z >>> 27)) * 0x94d049bb133111ebL;
        return z ^ (z >>> 31);
    }

    
Returns the 32 high bits of Stafford variant 4 mix64 function as int.

/**
     * Returns the 32 high bits of Stafford variant 4 mix64 function as int.
     */
    private static int mix32(long z) {
        z = (z ^ (z >>> 33)) * 0x62a9d9ed799705f5L;
        return (int)(((z ^ (z >>> 28)) * 0xcb24d0a5c88c35b3L) >>> 32);
    }

    
Returns the gamma value to use for a new split instance.

/**
     * Returns the gamma value to use for a new split instance.
     */
    private static long mixGamma(long z) {
        z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; // MurmurHash3 mix constants
        z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L;
        z = (z ^ (z >>> 33)) | 1L;                  // force to be odd
        int n = Long.bitCount(z ^ (z >>> 1));       // ensure enough transitions
        return (n < 24) ? z ^ 0xaaaaaaaaaaaaaaaaL : z;
    }

    
Adds gamma to seed.

/**
     * Adds gamma to seed.
     */
    private long nextSeed() {
        return seed += gamma;
    }

    // IllegalArgumentException messages
    static final String BAD_BOUND = "bound must be positive";
    static final String BAD_RANGE = "bound must be greater than origin";
    static final String BAD_SIZE  = "size must be non-negative";

    
The seed generator for default constructors.

/**
     * The seed generator for default constructors.
     */
    private static final AtomicLong defaultGen
        = new AtomicLong(mix64(System.currentTimeMillis()) ^
                         mix64(System.nanoTime()));

    // at end of <clinit> to survive static initialization circularity
    static {
        if (java.security.AccessController.doPrivileged(
            new java.security.PrivilegedAction<Boolean>() {
                public Boolean run() {
                    return Boolean.getBoolean("java.util.secureRandomSeed");
                }})) {
            byte[] seedBytes = java.security.SecureRandom.getSeed(8);
            long s = (long)seedBytes[0] & 0xffL;
            for (int i = 1; i < 8; ++i)
                s = (s << 8) | ((long)seedBytes[i] & 0xffL);
            defaultGen.set(s);
        }
    }

    /*
     * Internal versions of nextX methods used by streams, as well as
     * the public nextX(origin, bound) methods.  These exist mainly to
     * avoid the need for multiple versions of stream spliterators
     * across the different exported forms of streams.
     */

    
The form of nextLong used by LongStream Spliterators.  If
origin is greater than bound, acts as unbounded form of
nextLong, else as bounded form.

Params:
  • origin – the least value, unless greater than bound
  • bound – the upper bound (exclusive), must not equal origin
Returns:a pseudorandom value
/**
     * 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) {
        /*
         * Four Cases:
         *
         * 1. If the arguments indicate unbounded form, act as
         * nextLong().
         *
         * 2. If the range is an exact power of two, apply the
         * associated bit mask.
         *
         * 3. If the range is positive, loop to avoid potential bias
         * when the implicit nextLong() bound (2<sup>64</sup>) is not
         * evenly divisible by the range. The loop rejects candidates
         * computed from otherwise over-represented values.  The
         * expected number of iterations under an ideal generator
         * varies from 1 to 2, depending on the bound. The loop itself
         * takes an unlovable form. Because the first candidate is
         * already available, we need a break-in-the-middle
         * construction, which is concisely but cryptically performed
         * within the while-condition of a body-less for loop.
         *
         * 4. Otherwise, the range cannot be represented as a positive
         * long.  The loop repeatedly generates unbounded longs until
         * obtaining a candidate meeting constraints (with an expected
         * number of iterations of less than two).
         */

        long r = mix64(nextSeed());
        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 = mix64(nextSeed()) >>> 1) // retry
                    ;
                r += origin;
            }
            else {              // range not representable as long
                while (r < origin || r >= bound)
                    r = mix64(nextSeed());
            }
        }
        return r;
    }

    
The form of nextInt used by IntStream Spliterators.
Exactly the same as long version, except for types.

Params:
  • origin – the least value, unless greater than bound
  • bound – the upper bound (exclusive), must not equal origin
Returns:a pseudorandom value
/**
     * The form of nextInt used by IntStream Spliterators.
     * Exactly the same as long version, except for types.
     *
     * @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) {
        int r = mix32(nextSeed());
        if (origin < bound) {
            int n = bound - origin, m = n - 1;
            if ((n & m) == 0)
                r = (r & m) + origin;
            else if (n > 0) {
                for (int u = r >>> 1;
                     u + m - (r = u % n) < 0;
                     u = mix32(nextSeed()) >>> 1)
                    ;
                r += origin;
            }
            else {
                while (r < origin || r >= bound)
                    r = mix32(nextSeed());
            }
        }
        return r;
    }

    
The form of nextDouble used by DoubleStream Spliterators.

Params:
  • origin – the least value, unless greater than bound
  • bound – the upper bound (exclusive), must not equal origin
Returns:a pseudorandom value
/**
     * 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 = (nextLong() >>> 11) * DOUBLE_UNIT;
        if (origin < bound) {
            r = r * (bound - origin) + origin;
            if (r >= bound) // correct for rounding
                r = Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
        }
        return r;
    }

    /* ---------------- public methods ---------------- */

    
Creates a new SplittableRandom instance using the specified
initial seed. SplittableRandom instances created with the same
seed in the same program generate identical sequences of values.

Params:
  • seed – the initial seed
/**
     * Creates a new SplittableRandom instance using the specified
     * initial seed. SplittableRandom instances created with the same
     * seed in the same program generate identical sequences of values.
     *
     * @param seed the initial seed
     */
    public SplittableRandom(long seed) {
        this(seed, GOLDEN_GAMMA);
    }

    
Creates a new SplittableRandom instance that is likely to
generate sequences of values that are statistically independent
of those of any other instances in the current program; and
may, and typically does, vary across program invocations.

/**
     * Creates a new SplittableRandom instance that is likely to
     * generate sequences of values that are statistically independent
     * of those of any other instances in the current program; and
     * may, and typically does, vary across program invocations.
     */
    public SplittableRandom() { // emulate defaultGen.split()
        long s = defaultGen.getAndAdd(GOLDEN_GAMMA << 1);
        this.seed = mix64(s);
        this.gamma = mixGamma(s + GOLDEN_GAMMA);
    }

    
Constructs and returns a new SplittableRandom instance that shares no mutable state with this instance. However, with very high probability, the set of values collectively generated by the two objects has the same statistical properties as if the same quantity of values were generated by a single thread using a single SplittableRandom object. Either or both of the two objects may be further split using the split() method, and the same expected statistical properties apply to the entire set of generators constructed by such recursive splitting. 
Returns:the new SplittableRandom instance
/**
     * Constructs and returns a new SplittableRandom instance that
     * shares no mutable state with this instance. However, with very
     * high probability, the set of values collectively generated by
     * the two objects has the same statistical properties as if the
     * same quantity of values were generated by a single thread using
     * a single SplittableRandom object.  Either or both of the two
     * objects may be further split using the {@code split()} method,
     * and the same expected statistical properties apply to the
     * entire set of generators constructed by such recursive
     * splitting.
     *
     * @return the new SplittableRandom instance
     */
    public SplittableRandom split() {
        return new SplittableRandom(nextLong(), mixGamma(nextSeed()));
    }

    
Fills a user-supplied byte array with generated pseudorandom bytes.

Params:
  • bytes – the byte array to fill with pseudorandom bytes
Throws:
Since: 10
/**
     * Fills a user-supplied byte array with generated pseudorandom bytes.
     *
     * @param  bytes the byte array to fill with pseudorandom bytes
     * @throws NullPointerException if bytes is null
     * @since  10
     */
    public void nextBytes(byte[] bytes) {
        int i = 0;
        int len = bytes.length;
        for (int words = len >> 3; words--> 0; ) {
            long rnd = nextLong();
            for (int n = 8; n--> 0; rnd >>>= Byte.SIZE)
                bytes[i++] = (byte)rnd;
        }
        if (i < len)
            for (long rnd = nextLong(); i < len; rnd >>>= Byte.SIZE)
                bytes[i++] = (byte)rnd;
    }

    
Returns a pseudorandom int value. 
Returns:a pseudorandom int value
/**
     * Returns a pseudorandom {@code int} value.
     *
     * @return a pseudorandom {@code int} value
     */
    public int nextInt() {
        return mix32(nextSeed());
    }

    
Returns a pseudorandom int value between zero (inclusive) and the specified bound (exclusive). 
Params:
  • bound – the upper bound (exclusive).  Must be positive.
Throws:
Returns:a pseudorandom int value between zero (inclusive) and the bound (exclusive)
/**
     * Returns a pseudorandom {@code int} value between zero (inclusive)
     * and the specified bound (exclusive).
     *
     * @param bound the upper bound (exclusive).  Must be positive.
     * @return a pseudorandom {@code int} value between zero
     *         (inclusive) and the bound (exclusive)
     * @throws IllegalArgumentException if {@code bound} is not positive
     */
    public int nextInt(int bound) {
        if (bound <= 0)
            throw new IllegalArgumentException(BAD_BOUND);
        // Specialize internalNextInt for origin 0
        int r = mix32(nextSeed());
        int m = bound - 1;
        if ((bound & m) == 0) // power of two
            r &= m;
        else { // reject over-represented candidates
            for (int u = r >>> 1;
                 u + m - (r = u % bound) < 0;
                 u = mix32(nextSeed()) >>> 1)
                ;
        }
        return r;
    }

    
Returns a pseudorandom int value between the specified origin (inclusive) and the specified bound (exclusive). 
Params:
  • origin – the least value returned
  • bound – the upper bound (exclusive)
Throws:
Returns:a pseudorandom int value between the origin (inclusive) and the bound (exclusive)
/**
     * Returns a pseudorandom {@code int} value between the specified
     * origin (inclusive) and the specified bound (exclusive).
     *
     * @param origin the least value returned
     * @param bound the upper bound (exclusive)
     * @return a pseudorandom {@code int} value between the origin
     *         (inclusive) and the bound (exclusive)
     * @throws IllegalArgumentException if {@code origin} is greater than
     *         or equal to {@code bound}
     */
    public int nextInt(int origin, int bound) {
        if (origin >= bound)
            throw new IllegalArgumentException(BAD_RANGE);
        return internalNextInt(origin, bound);
    }

    
Returns a pseudorandom long value. 
Returns:a pseudorandom long value
/**
     * Returns a pseudorandom {@code long} value.
     *
     * @return a pseudorandom {@code long} value
     */
    public long nextLong() {
        return mix64(nextSeed());
    }

    
Returns a pseudorandom long value between zero (inclusive) and the specified bound (exclusive). 
Params:
  • bound – the upper bound (exclusive).  Must be positive.
Throws:
Returns:a pseudorandom long value between zero (inclusive) and the bound (exclusive)
/**
     * Returns a pseudorandom {@code long} value between zero (inclusive)
     * and the specified bound (exclusive).
     *
     * @param bound the upper bound (exclusive).  Must be positive.
     * @return a pseudorandom {@code long} value between zero
     *         (inclusive) and the bound (exclusive)
     * @throws IllegalArgumentException if {@code bound} is not positive
     */
    public long nextLong(long bound) {
        if (bound <= 0)
            throw new IllegalArgumentException(BAD_BOUND);
        // Specialize internalNextLong for origin 0
        long r = mix64(nextSeed());
        long m = bound - 1;
        if ((bound & m) == 0L) // power of two
            r &= m;
        else { // reject over-represented candidates
            for (long u = r >>> 1;
                 u + m - (r = u % bound) < 0L;
                 u = mix64(nextSeed()) >>> 1)
                ;
        }
        return r;
    }

    
Returns a pseudorandom long value between the specified origin (inclusive) and the specified bound (exclusive). 
Params:
  • origin – the least value returned
  • bound – the upper bound (exclusive)
Throws:
Returns:a pseudorandom long value between the origin (inclusive) and the bound (exclusive)
/**
     * Returns a pseudorandom {@code long} value between the specified
     * origin (inclusive) and the specified bound (exclusive).
     *
     * @param origin the least value returned
     * @param bound the upper bound (exclusive)
     * @return a pseudorandom {@code long} value between the origin
     *         (inclusive) and the bound (exclusive)
     * @throws IllegalArgumentException if {@code origin} is greater than
     *         or equal to {@code bound}
     */
    public long nextLong(long origin, long bound) {
        if (origin >= bound)
            throw new IllegalArgumentException(BAD_RANGE);
        return internalNextLong(origin, bound);
    }

    
Returns a pseudorandom double value between zero (inclusive) and one (exclusive). 
Returns:a pseudorandom double value between zero (inclusive) and one (exclusive)
/**
     * Returns a pseudorandom {@code double} value between zero
     * (inclusive) and one (exclusive).
     *
     * @return a pseudorandom {@code double} value between zero
     *         (inclusive) and one (exclusive)
     */
    public double nextDouble() {
        return (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT;
    }

    
Returns a pseudorandom double value between 0.0 (inclusive) and the specified bound (exclusive). 
Params:
  • bound – the upper bound (exclusive).  Must be positive.
Throws:
Returns:a pseudorandom double value between zero (inclusive) and the bound (exclusive)
/**
     * Returns a pseudorandom {@code double} value between 0.0
     * (inclusive) and the specified bound (exclusive).
     *
     * @param bound the upper bound (exclusive).  Must be positive.
     * @return a pseudorandom {@code double} value between zero
     *         (inclusive) and the bound (exclusive)
     * @throws IllegalArgumentException if {@code bound} is not positive
     */
    public double nextDouble(double bound) {
        if (!(bound > 0.0))
            throw new IllegalArgumentException(BAD_BOUND);
        double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound;
        return (result < bound) ?  result : // correct for rounding
            Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
    }

    
Returns a pseudorandom double value between the specified origin (inclusive) and bound (exclusive). 
Params:
  • origin – the least value returned
  • bound – the upper bound (exclusive)
Throws:
Returns:a pseudorandom double value between the origin (inclusive) and the bound (exclusive)
/**
     * Returns a pseudorandom {@code double} value between the specified
     * origin (inclusive) and bound (exclusive).
     *
     * @param origin the least value returned
     * @param bound the upper bound (exclusive)
     * @return a pseudorandom {@code double} value between the origin
     *         (inclusive) and the bound (exclusive)
     * @throws IllegalArgumentException if {@code origin} is greater than
     *         or equal to {@code bound}
     */
    public double nextDouble(double origin, double bound) {
        if (!(origin < bound))
            throw new IllegalArgumentException(BAD_RANGE);
        return internalNextDouble(origin, bound);
    }

    
Returns a pseudorandom boolean value. 
Returns:a pseudorandom boolean value
/**
     * Returns a pseudorandom {@code boolean} value.
     *
     * @return a pseudorandom {@code boolean} value
     */
    public boolean nextBoolean() {
        return mix32(nextSeed()) < 0;
    }

    // stream methods, coded in a way intended to better isolate for
    // maintenance purposes the small differences across forms.

    
Returns a stream producing the given streamSize number of pseudorandom int values from this generator and/or one split from it. 
Params:
  • streamSize – the number of values to generate
Throws:
Returns:a stream of pseudorandom int values
/**
     * Returns a stream producing the given {@code streamSize} number
     * of pseudorandom {@code int} values from this generator and/or
     * one split from it.
     *
     * @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
     */
    public IntStream ints(long streamSize) {
        if (streamSize < 0L)
            throw new IllegalArgumentException(BAD_SIZE);
        return StreamSupport.intStream
            (new RandomIntsSpliterator
             (this, 0L, streamSize, Integer.MAX_VALUE, 0),
             false);
    }

    
Returns an effectively unlimited stream of pseudorandom int values from this generator and/or one split from it. 
Implementation Note:This method is implemented to be equivalent to 
ints(Long.MAX_VALUE).
Returns:a stream of pseudorandom int values
/**
     * Returns an effectively unlimited stream of pseudorandom {@code int}
     * values from this generator and/or one split from it.
     *
     * @implNote This method is implemented to be equivalent to {@code
     * ints(Long.MAX_VALUE)}.
     *
     * @return a stream of pseudorandom {@code int} values
     */
    public IntStream ints() {
        return StreamSupport.intStream
            (new RandomIntsSpliterator
             (this, 0L, Long.MAX_VALUE, Integer.MAX_VALUE, 0),
             false);
    }

    
Returns a stream producing the given streamSize number of pseudorandom int values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive). 
Params:
  • streamSize – the number of values to generate
  • randomNumberOrigin – the origin (inclusive) of each random value
  • randomNumberBound – the bound (exclusive) of each random value
Throws:
  • IllegalArgumentException – if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound
Returns:a stream of pseudorandom int values, each with the given origin (inclusive) and bound (exclusive)
/**
     * Returns a stream producing the given {@code streamSize} number
     * of pseudorandom {@code int} values from this generator and/or one split
     * from it; each value conforms to the given origin (inclusive) and bound
     * (exclusive).
     *
     * @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}
     */
    public IntStream ints(long streamSize, int randomNumberOrigin,
                          int randomNumberBound) {
        if (streamSize < 0L)
            throw new IllegalArgumentException(BAD_SIZE);
        if (randomNumberOrigin >= randomNumberBound)
            throw new IllegalArgumentException(BAD_RANGE);
        return StreamSupport.intStream
            (new RandomIntsSpliterator
             (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
             false);
    }

    
Returns an effectively unlimited stream of pseudorandom 
int values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive). 
Params:
  • randomNumberOrigin – the origin (inclusive) of each random value
  • randomNumberBound – the bound (exclusive) of each random value
Throws:
Implementation Note:This method is implemented to be equivalent to 
ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound).
Returns:a stream of pseudorandom int values, each with the given origin (inclusive) and bound (exclusive)
/**
     * Returns an effectively unlimited stream of pseudorandom {@code
     * int} values from this generator and/or one split from it; each value
     * conforms to the given origin (inclusive) and bound (exclusive).
     *
     * @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}
     */
    public IntStream ints(int randomNumberOrigin, int randomNumberBound) {
        if (randomNumberOrigin >= randomNumberBound)
            throw new IllegalArgumentException(BAD_RANGE);
        return StreamSupport.intStream
            (new RandomIntsSpliterator
             (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
             false);
    }

    
Returns a stream producing the given streamSize number of pseudorandom long values from this generator and/or one split from it. 
Params:
  • streamSize – the number of values to generate
Throws:
Returns:a stream of pseudorandom long values
/**
     * Returns a stream producing the given {@code streamSize} number
     * of pseudorandom {@code long} values from this generator and/or
     * one split from it.
     *
     * @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
     */
    public LongStream longs(long streamSize) {
        if (streamSize < 0L)
            throw new IllegalArgumentException(BAD_SIZE);
        return StreamSupport.longStream
            (new RandomLongsSpliterator
             (this, 0L, streamSize, Long.MAX_VALUE, 0L),
             false);
    }

    
Returns an effectively unlimited stream of pseudorandom 
long values from this generator and/or one split from it. 
Implementation Note:This method is implemented to be equivalent to 
longs(Long.MAX_VALUE).
Returns:a stream of pseudorandom long values
/**
     * Returns an effectively unlimited stream of pseudorandom {@code
     * long} values from this generator and/or one split from it.
     *
     * @implNote This method is implemented to be equivalent to {@code
     * longs(Long.MAX_VALUE)}.
     *
     * @return a stream of pseudorandom {@code long} values
     */
    public LongStream longs() {
        return StreamSupport.longStream
            (new RandomLongsSpliterator
             (this, 0L, Long.MAX_VALUE, Long.MAX_VALUE, 0L),
             false);
    }

    
Returns a stream producing the given streamSize number of pseudorandom long values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive). 
Params:
  • streamSize – the number of values to generate
  • randomNumberOrigin – the origin (inclusive) of each random value
  • randomNumberBound – the bound (exclusive) of each random value
Throws:
  • IllegalArgumentException – if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound
Returns:a stream of pseudorandom long values, each with the given origin (inclusive) and bound (exclusive)
/**
     * Returns a stream producing the given {@code streamSize} number of
     * pseudorandom {@code long} values from this generator and/or one split
     * from it; each value conforms to the given origin (inclusive) and bound
     * (exclusive).
     *
     * @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}
     */
    public LongStream longs(long streamSize, long randomNumberOrigin,
                            long randomNumberBound) {
        if (streamSize < 0L)
            throw new IllegalArgumentException(BAD_SIZE);
        if (randomNumberOrigin >= randomNumberBound)
            throw new IllegalArgumentException(BAD_RANGE);
        return StreamSupport.longStream
            (new RandomLongsSpliterator
             (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
             false);
    }

    
Returns an effectively unlimited stream of pseudorandom 
long values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive). 
Params:
  • randomNumberOrigin – the origin (inclusive) of each random value
  • randomNumberBound – the bound (exclusive) of each random value
Throws:
Implementation Note:This method is implemented to be equivalent to 
longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound).
Returns:a stream of pseudorandom long values, each with the given origin (inclusive) and bound (exclusive)
/**
     * Returns an effectively unlimited stream of pseudorandom {@code
     * long} values from this generator and/or one split from it; each value
     * conforms to the given origin (inclusive) and bound (exclusive).
     *
     * @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}
     */
    public LongStream longs(long randomNumberOrigin, long randomNumberBound) {
        if (randomNumberOrigin >= randomNumberBound)
            throw new IllegalArgumentException(BAD_RANGE);
        return StreamSupport.longStream
            (new RandomLongsSpliterator
             (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
             false);
    }

    
Returns a stream producing the given streamSize number of pseudorandom double values from this generator and/or one split from it; each value is between zero (inclusive) and one (exclusive). 
Params:
  • streamSize – the number of values to generate
Throws:
Returns:a stream of double values
/**
     * Returns a stream producing the given {@code streamSize} number of
     * pseudorandom {@code double} values from this generator and/or one split
     * from it; each value is between zero (inclusive) and one (exclusive).
     *
     * @param streamSize the number of values to generate
     * @return a stream of {@code double} values
     * @throws IllegalArgumentException if {@code streamSize} is
     *         less than zero
     */
    public DoubleStream doubles(long streamSize) {
        if (streamSize < 0L)
            throw new IllegalArgumentException(BAD_SIZE);
        return StreamSupport.doubleStream
            (new RandomDoublesSpliterator
             (this, 0L, streamSize, Double.MAX_VALUE, 0.0),
             false);
    }

    
Returns an effectively unlimited stream of pseudorandom 
double values from this generator and/or one split from it; each value is between zero (inclusive) and one (exclusive). 
Implementation Note:This method is implemented to be equivalent to 
doubles(Long.MAX_VALUE).
Returns:a stream of pseudorandom double values
/**
     * Returns an effectively unlimited stream of pseudorandom {@code
     * double} values from this generator and/or one split from it; each value
     * is between zero (inclusive) and one (exclusive).
     *
     * @implNote This method is implemented to be equivalent to {@code
     * doubles(Long.MAX_VALUE)}.
     *
     * @return a stream of pseudorandom {@code double} values
     */
    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 streamSize number of pseudorandom double values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive). 
Params:
  • streamSize – the number of values to generate
  • randomNumberOrigin – the origin (inclusive) of each random value
  • randomNumberBound – the bound (exclusive) of each random value
Throws:
  • IllegalArgumentException – if streamSize is less than zero, or randomNumberOrigin is greater than or equal to randomNumberBound
Returns:a stream of pseudorandom double values, each with the given origin (inclusive) and bound (exclusive)
/**
     * Returns a stream producing the given {@code streamSize} number of
     * pseudorandom {@code double} values from this generator and/or one split
     * from it; each value conforms to the given origin (inclusive) and bound
     * (exclusive).
     *
     * @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, or {@code randomNumberOrigin}
     *         is greater than or equal to {@code randomNumberBound}
     */
    public DoubleStream doubles(long streamSize, double randomNumberOrigin,
                                double randomNumberBound) {
        if (streamSize < 0L)
            throw new IllegalArgumentException(BAD_SIZE);
        if (!(randomNumberOrigin < randomNumberBound))
            throw new IllegalArgumentException(BAD_RANGE);
        return StreamSupport.doubleStream
            (new RandomDoublesSpliterator
             (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
             false);
    }

    
Returns an effectively unlimited stream of pseudorandom 
double values from this generator and/or one split from it; each value conforms to the given origin (inclusive) and bound (exclusive). 
Params:
  • randomNumberOrigin – the origin (inclusive) of each random value
  • randomNumberBound – the bound (exclusive) of each random value
Throws:
Implementation Note:This method is implemented to be equivalent to 
doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound).
Returns:a stream of pseudorandom double values, each with the given origin (inclusive) and bound (exclusive)
/**
     * Returns an effectively unlimited stream of pseudorandom {@code
     * double} values from this generator and/or one split from it; each value
     * conforms to the given origin (inclusive) and bound (exclusive).
     *
     * @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}
     */
    public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
        if (!(randomNumberOrigin < randomNumberBound))
            throw new IllegalArgumentException(BAD_RANGE);
        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.

/**
     * 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.
     */
    private static final class RandomIntsSpliterator
            implements Spliterator.OfInt {
        final SplittableRandom rng;
        long index;
        final long fence;
        final int origin;
        final int bound;
        RandomIntsSpliterator(SplittableRandom 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.split(), 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;
                SplittableRandom r = rng;
                int o = origin, b = bound;
                do {
                    consumer.accept(r.internalNextInt(o, b));
                } while (++i < f);
            }
        }
    }

    
Spliterator for long streams.

/**
     * Spliterator for long streams.
     */
    private static final class RandomLongsSpliterator
            implements Spliterator.OfLong {
        final SplittableRandom rng;
        long index;
        final long fence;
        final long origin;
        final long bound;
        RandomLongsSpliterator(SplittableRandom 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.split(), 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;
                SplittableRandom r = rng;
                long o = origin, b = bound;
                do {
                    consumer.accept(r.internalNextLong(o, b));
                } while (++i < f);
            }
        }

    }

    
Spliterator for double streams.

/**
     * Spliterator for double streams.
     */
    private static final class RandomDoublesSpliterator
            implements Spliterator.OfDouble {
        final SplittableRandom rng;
        long index;
        final long fence;
        final double origin;
        final double bound;
        RandomDoublesSpliterator(SplittableRandom 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.split(), 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;
                SplittableRandom r = rng;
                double o = origin, b = bound;
                do {
                    consumer.accept(r.internalNextDouble(o, b));
                } while (++i < f);
            }
        }
    }

}