--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.base/share/classes/java/util/concurrent/ThreadLocalRandom.java Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,1101 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+package java.util.concurrent;
+
+import java.io.ObjectStreamField;
+import java.net.NetworkInterface;
+import java.util.Enumeration;
+import java.util.Random;
+import java.util.Spliterator;
+import java.util.concurrent.atomic.AtomicInteger;
+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 random number generator isolated to the current thread. Like the
+ * global {@link java.util.Random} generator used by the {@link
+ * java.lang.Math} class, a {@code ThreadLocalRandom} is initialized
+ * with an internally generated seed that may not otherwise be
+ * modified. When applicable, use of {@code ThreadLocalRandom} rather
+ * than shared {@code Random} objects in concurrent programs will
+ * typically encounter much less overhead and contention. Use of
+ * {@code ThreadLocalRandom} is particularly appropriate when multiple
+ * tasks (for example, each a {@link ForkJoinTask}) use random numbers
+ * in parallel in thread pools.
+ *
+ * <p>Usages of this class should typically be of the form:
+ * {@code ThreadLocalRandom.current().nextX(...)} (where
+ * {@code X} is {@code Int}, {@code Long}, etc).
+ * When all usages are of this form, it is never possible to
+ * accidently share a {@code ThreadLocalRandom} across multiple threads.
+ *
+ * <p>This class also provides additional commonly used bounded random
+ * generation methods.
+ *
+ * <p>Instances of {@code ThreadLocalRandom} 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}.
+ *
+ * @since 1.7
+ * @author Doug Lea
+ */
+public class ThreadLocalRandom extends Random {
+ /*
+ * This class implements the java.util.Random API (and subclasses
+ * Random) using a single static instance that accesses random
+ * number state held in class Thread (primarily, field
+ * threadLocalRandomSeed). In doing so, it also provides a home
+ * for managing package-private utilities that rely on exactly the
+ * same state as needed to maintain the ThreadLocalRandom
+ * instances. We leverage the need for an initialization flag
+ * field to also use it as a "probe" -- a self-adjusting thread
+ * hash used for contention avoidance, as well as a secondary
+ * simpler (xorShift) random seed that is conservatively used to
+ * avoid otherwise surprising users by hijacking the
+ * ThreadLocalRandom sequence. The dual use is a marriage of
+ * convenience, but is a simple and efficient way of reducing
+ * application-level overhead and footprint of most concurrent
+ * programs.
+ *
+ * Even though this class subclasses java.util.Random, it uses the
+ * same basic algorithm as java.util.SplittableRandom. (See its
+ * internal documentation for explanations, which are not repeated
+ * here.) Because ThreadLocalRandoms are not splittable
+ * though, we use only a single 64bit gamma.
+ *
+ * Because this class is in a different package than class Thread,
+ * field access methods use Unsafe to bypass access control rules.
+ * To conform to the requirements of the Random superclass
+ * constructor, the common static ThreadLocalRandom maintains an
+ * "initialized" field for the sake of rejecting user calls to
+ * setSeed while still allowing a call from constructor. Note
+ * that serialization is completely unnecessary because there is
+ * only a static singleton. But we generate a serial form
+ * containing "rnd" and "initialized" fields to ensure
+ * compatibility across versions.
+ *
+ * Implementations of non-core methods are mostly the same as in
+ * SplittableRandom, that were in part derived from a previous
+ * version of this class.
+ *
+ * The nextLocalGaussian ThreadLocal supports the very rarely used
+ * nextGaussian method by providing a holder for the second of a
+ * pair of them. As is true for the base class version of this
+ * method, this time/space tradeoff is probably never worthwhile,
+ * but we provide identical statistical properties.
+ */
+
+ /** Generates per-thread initialization/probe field */
+ private static final AtomicInteger probeGenerator =
+ new AtomicInteger();
+
+ /**
+ * The next seed for default constructors.
+ */
+ private static final AtomicLong seeder = new AtomicLong(initialSeed());
+
+ private static long initialSeed() {
+ String pp = java.security.AccessController.doPrivileged(
+ new sun.security.action.GetPropertyAction(
+ "java.util.secureRandomSeed"));
+ if (pp != null && pp.equalsIgnoreCase("true")) {
+ 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);
+ return s;
+ }
+ long h = 0L;
+ try {
+ Enumeration<NetworkInterface> ifcs =
+ NetworkInterface.getNetworkInterfaces();
+ boolean retry = false; // retry once if getHardwareAddress is null
+ while (ifcs.hasMoreElements()) {
+ NetworkInterface ifc = ifcs.nextElement();
+ if (!ifc.isVirtual()) { // skip fake addresses
+ byte[] bs = ifc.getHardwareAddress();
+ if (bs != null) {
+ int n = bs.length;
+ int m = Math.min(n >>> 1, 4);
+ for (int i = 0; i < m; ++i)
+ h = (h << 16) ^ (bs[i] << 8) ^ bs[n-1-i];
+ if (m < 4)
+ h = (h << 8) ^ bs[n-1-m];
+ h = mix64(h);
+ break;
+ }
+ else if (!retry)
+ retry = true;
+ else
+ break;
+ }
+ }
+ } catch (Exception ignore) {
+ }
+ return (h ^ mix64(System.currentTimeMillis()) ^
+ mix64(System.nanoTime()));
+ }
+
+ /**
+ * The seed increment
+ */
+ private static final long GAMMA = 0x9e3779b97f4a7c15L;
+
+ /**
+ * The increment for generating probe values
+ */
+ private static final int PROBE_INCREMENT = 0x9e3779b9;
+
+ /**
+ * The increment of seeder per new instance
+ */
+ private static final long SEEDER_INCREMENT = 0xbb67ae8584caa73bL;
+
+ // Constants from SplittableRandom
+ private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53)
+ private static final float FLOAT_UNIT = 0x1.0p-24f; // 1.0f / (1 << 24)
+
+ /** Rarely-used holder for the second of a pair of Gaussians */
+ private static final ThreadLocal<Double> nextLocalGaussian =
+ new ThreadLocal<Double>();
+
+ private static long mix64(long z) {
+ z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL;
+ z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L;
+ return z ^ (z >>> 33);
+ }
+
+ private static int mix32(long z) {
+ z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL;
+ return (int)(((z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L) >>> 32);
+ }
+
+ /**
+ * Field used only during singleton initialization.
+ * True when constructor completes.
+ */
+ boolean initialized;
+
+ /** Constructor used only for static singleton */
+ private ThreadLocalRandom() {
+ initialized = true; // false during super() call
+ }
+
+ /** The common ThreadLocalRandom */
+ static final ThreadLocalRandom instance = new ThreadLocalRandom();
+
+ /**
+ * Initialize Thread fields for the current thread. Called only
+ * when Thread.threadLocalRandomProbe is zero, indicating that a
+ * thread local seed value needs to be generated. Note that even
+ * though the initialization is purely thread-local, we need to
+ * rely on (static) atomic generators to initialize the values.
+ */
+ static final void localInit() {
+ int p = probeGenerator.addAndGet(PROBE_INCREMENT);
+ int probe = (p == 0) ? 1 : p; // skip 0
+ long seed = mix64(seeder.getAndAdd(SEEDER_INCREMENT));
+ Thread t = Thread.currentThread();
+ UNSAFE.putLong(t, SEED, seed);
+ UNSAFE.putInt(t, PROBE, probe);
+ }
+
+ /**
+ * Returns the current thread's {@code ThreadLocalRandom}.
+ *
+ * @return the current thread's {@code ThreadLocalRandom}
+ */
+ public static ThreadLocalRandom current() {
+ if (UNSAFE.getInt(Thread.currentThread(), PROBE) == 0)
+ localInit();
+ return instance;
+ }
+
+ /**
+ * Throws {@code UnsupportedOperationException}. Setting seeds in
+ * this generator is not supported.
+ *
+ * @throws UnsupportedOperationException always
+ */
+ public void setSeed(long seed) {
+ // only allow call from super() constructor
+ if (initialized)
+ throw new UnsupportedOperationException();
+ }
+
+ final long nextSeed() {
+ Thread t; long r; // read and update per-thread seed
+ UNSAFE.putLong(t = Thread.currentThread(), SEED,
+ r = UNSAFE.getLong(t, SEED) + GAMMA);
+ return r;
+ }
+
+ // We must define this, but never use it.
+ protected int next(int bits) {
+ return (int)(mix64(nextSeed()) >>> (64 - bits));
+ }
+
+ // 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";
+
+ /**
+ * 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 = 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.
+ *
+ * @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.
+ *
+ * @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;
+ }
+
+ /**
+ * Returns a pseudorandom {@code int} value.
+ *
+ * @return a pseudorandom {@code int} value
+ */
+ public int nextInt() {
+ return mix32(nextSeed());
+ }
+
+ /**
+ * 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(BadBound);
+ 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 {@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(BadRange);
+ return internalNextInt(origin, bound);
+ }
+
+ /**
+ * Returns a pseudorandom {@code long} value.
+ *
+ * @return a pseudorandom {@code long} value
+ */
+ public long nextLong() {
+ return mix64(nextSeed());
+ }
+
+ /**
+ * 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(BadBound);
+ 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 {@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(BadRange);
+ return internalNextLong(origin, bound);
+ }
+
+ /**
+ * 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 {@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(BadBound);
+ double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound;
+ return (result < bound) ? result : // correct for rounding
+ Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
+ }
+
+ /**
+ * 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(BadRange);
+ return internalNextDouble(origin, bound);
+ }
+
+ /**
+ * Returns a pseudorandom {@code boolean} value.
+ *
+ * @return a pseudorandom {@code boolean} value
+ */
+ public boolean nextBoolean() {
+ return mix32(nextSeed()) < 0;
+ }
+
+ /**
+ * Returns a pseudorandom {@code float} value between zero
+ * (inclusive) and one (exclusive).
+ *
+ * @return a pseudorandom {@code float} value between zero
+ * (inclusive) and one (exclusive)
+ */
+ public float nextFloat() {
+ return (mix32(nextSeed()) >>> 8) * FLOAT_UNIT;
+ }
+
+ public double nextGaussian() {
+ // Use nextLocalGaussian instead of nextGaussian field
+ Double d = nextLocalGaussian.get();
+ if (d != null) {
+ nextLocalGaussian.set(null);
+ return d.doubleValue();
+ }
+ 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);
+ nextLocalGaussian.set(new Double(v2 * multiplier));
+ 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.
+ *
+ * @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
+ (0L, streamSize, Integer.MAX_VALUE, 0),
+ false);
+ }
+
+ /**
+ * Returns an effectively unlimited stream of pseudorandom {@code int}
+ * values.
+ *
+ * @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
+ (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).
+ *
+ * @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
+ (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).
+ *
+ * @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
+ (0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
+ false);
+ }
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number of
+ * pseudorandom {@code long} values.
+ *
+ * @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
+ (0L, streamSize, Long.MAX_VALUE, 0L),
+ false);
+ }
+
+ /**
+ * Returns an effectively unlimited stream of pseudorandom {@code long}
+ * values.
+ *
+ * @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
+ (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).
+ *
+ * @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
+ (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).
+ *
+ * @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
+ (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).
+ *
+ * @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
+ (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).
+ *
+ * @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
+ (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).
+ *
+ * @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
+ (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).
+ *
+ * @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
+ (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 {
+ long index;
+ final long fence;
+ final int origin;
+ final int bound;
+ RandomIntsSpliterator(long index, long fence,
+ int origin, int bound) {
+ 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(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(ThreadLocalRandom.current().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;
+ int o = origin, b = bound;
+ ThreadLocalRandom rng = ThreadLocalRandom.current();
+ do {
+ consumer.accept(rng.internalNextInt(o, b));
+ } while (++i < f);
+ }
+ }
+ }
+
+ /**
+ * Spliterator for long streams.
+ */
+ static final class RandomLongsSpliterator implements Spliterator.OfLong {
+ long index;
+ final long fence;
+ final long origin;
+ final long bound;
+ RandomLongsSpliterator(long index, long fence,
+ long origin, long bound) {
+ 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(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(ThreadLocalRandom.current().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;
+ long o = origin, b = bound;
+ ThreadLocalRandom rng = ThreadLocalRandom.current();
+ do {
+ consumer.accept(rng.internalNextLong(o, b));
+ } while (++i < f);
+ }
+ }
+
+ }
+
+ /**
+ * Spliterator for double streams.
+ */
+ static final class RandomDoublesSpliterator implements Spliterator.OfDouble {
+ long index;
+ final long fence;
+ final double origin;
+ final double bound;
+ RandomDoublesSpliterator(long index, long fence,
+ double origin, double bound) {
+ 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(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(ThreadLocalRandom.current().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;
+ double o = origin, b = bound;
+ ThreadLocalRandom rng = ThreadLocalRandom.current();
+ do {
+ consumer.accept(rng.internalNextDouble(o, b));
+ } while (++i < f);
+ }
+ }
+ }
+
+
+ // Within-package utilities
+
+ /*
+ * Descriptions of the usages of the methods below can be found in
+ * the classes that use them. Briefly, a thread's "probe" value is
+ * a non-zero hash code that (probably) does not collide with
+ * other existing threads with respect to any power of two
+ * collision space. When it does collide, it is pseudo-randomly
+ * adjusted (using a Marsaglia XorShift). The nextSecondarySeed
+ * method is used in the same contexts as ThreadLocalRandom, but
+ * only for transient usages such as random adaptive spin/block
+ * sequences for which a cheap RNG suffices and for which it could
+ * in principle disrupt user-visible statistical properties of the
+ * main ThreadLocalRandom if we were to use it.
+ *
+ * Note: Because of package-protection issues, versions of some
+ * these methods also appear in some subpackage classes.
+ */
+
+ /**
+ * Returns the probe value for the current thread without forcing
+ * initialization. Note that invoking ThreadLocalRandom.current()
+ * can be used to force initialization on zero return.
+ */
+ static final int getProbe() {
+ return UNSAFE.getInt(Thread.currentThread(), PROBE);
+ }
+
+ /**
+ * Pseudo-randomly advances and records the given probe value for the
+ * given thread.
+ */
+ static final int advanceProbe(int probe) {
+ probe ^= probe << 13; // xorshift
+ probe ^= probe >>> 17;
+ probe ^= probe << 5;
+ UNSAFE.putInt(Thread.currentThread(), PROBE, probe);
+ return probe;
+ }
+
+ /**
+ * Returns the pseudo-randomly initialized or updated secondary seed.
+ */
+ static final int nextSecondarySeed() {
+ int r;
+ Thread t = Thread.currentThread();
+ if ((r = UNSAFE.getInt(t, SECONDARY)) != 0) {
+ r ^= r << 13; // xorshift
+ r ^= r >>> 17;
+ r ^= r << 5;
+ }
+ else {
+ localInit();
+ if ((r = (int)UNSAFE.getLong(t, SEED)) == 0)
+ r = 1; // avoid zero
+ }
+ UNSAFE.putInt(t, SECONDARY, r);
+ return r;
+ }
+
+ // Serialization support
+
+ private static final long serialVersionUID = -5851777807851030925L;
+
+ /**
+ * @serialField rnd long
+ * seed for random computations
+ * @serialField initialized boolean
+ * always true
+ */
+ private static final ObjectStreamField[] serialPersistentFields = {
+ new ObjectStreamField("rnd", long.class),
+ new ObjectStreamField("initialized", boolean.class),
+ };
+
+ /**
+ * Saves the {@code ThreadLocalRandom} to a stream (that is, serializes it).
+ * @param s the stream
+ * @throws java.io.IOException if an I/O error occurs
+ */
+ private void writeObject(java.io.ObjectOutputStream s)
+ throws java.io.IOException {
+
+ java.io.ObjectOutputStream.PutField fields = s.putFields();
+ fields.put("rnd", UNSAFE.getLong(Thread.currentThread(), SEED));
+ fields.put("initialized", true);
+ s.writeFields();
+ }
+
+ /**
+ * Returns the {@link #current() current} thread's {@code ThreadLocalRandom}.
+ * @return the {@link #current() current} thread's {@code ThreadLocalRandom}
+ */
+ private Object readResolve() {
+ return current();
+ }
+
+ // Unsafe mechanics
+ private static final sun.misc.Unsafe UNSAFE;
+ private static final long SEED;
+ private static final long PROBE;
+ private static final long SECONDARY;
+ static {
+ try {
+ UNSAFE = sun.misc.Unsafe.getUnsafe();
+ Class<?> tk = Thread.class;
+ SEED = UNSAFE.objectFieldOffset
+ (tk.getDeclaredField("threadLocalRandomSeed"));
+ PROBE = UNSAFE.objectFieldOffset
+ (tk.getDeclaredField("threadLocalRandomProbe"));
+ SECONDARY = UNSAFE.objectFieldOffset
+ (tk.getDeclaredField("threadLocalRandomSecondarySeed"));
+ } catch (Exception e) {
+ throw new Error(e);
+ }
+ }
+}