--- a/jdk/src/share/classes/java/util/concurrent/ThreadLocalRandom.java Wed Aug 28 09:46:55 2013 -0700
+++ b/jdk/src/share/classes/java/util/concurrent/ThreadLocalRandom.java Wed Aug 28 22:11:14 2013 +0200
@@ -37,11 +37,16 @@
import java.io.ObjectStreamField;
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
@@ -64,6 +69,10 @@
* <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.
+ *
* @since 1.7
* @author Doug Lea
*/
@@ -85,28 +94,26 @@
* 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.
- * The base functionality of Random methods is conveniently
- * isolated in method next(bits), that just reads and writes the
- * Thread field rather than its own field. However, 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.
+ * 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.
*
- * Per-thread initialization is similar to that in the no-arg
- * Random constructor, but we avoid correlation among not only
- * initial seeds of those created in different threads, but also
- * those created using class Random itself; while at the same time
- * not changing any statistical properties. So we use the same
- * underlying multiplicative sequence, but start the sequence far
- * away from the base version, and then merge (xor) current time
- * and per-thread probe bits to generate initial values.
+ * 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
@@ -115,24 +122,51 @@
* but we provide identical statistical properties.
*/
- // same constants as Random, but must be redeclared because private
- private static final long multiplier = 0x5DEECE66DL;
- private static final long addend = 0xBL;
- private static final long mask = (1L << 48) - 1;
- private static final int PROBE_INCREMENT = 0x61c88647;
-
- /** Generates the basis for per-thread initial seed values */
- private static final AtomicLong seedGenerator =
- new AtomicLong(1269533684904616924L);
-
/** Generates per-thread initialization/probe field */
private static final AtomicInteger probeGenerator =
- new AtomicInteger(0xe80f8647);
+ new AtomicInteger();
+
+ /**
+ * The next seed for default constructors.
+ */
+ private static final AtomicLong seeder =
+ new AtomicLong(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 = 1.0 / (1L << 53);
+ private static final float FLOAT_UNIT = 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.
@@ -155,16 +189,11 @@
* rely on (static) atomic generators to initialize the values.
*/
static final void localInit() {
- int p = probeGenerator.getAndAdd(PROBE_INCREMENT);
+ int p = probeGenerator.addAndGet(PROBE_INCREMENT);
int probe = (p == 0) ? 1 : p; // skip 0
- long current, next;
- do { // same sequence as j.u.Random but different initial value
- current = seedGenerator.get();
- next = current * 181783497276652981L;
- } while (!seedGenerator.compareAndSet(current, next));
- long r = next ^ ((long)probe << 32) ^ System.nanoTime();
+ long seed = mix64(seeder.getAndAdd(SEEDER_INCREMENT));
Thread t = Thread.currentThread();
- UNSAFE.putLong(t, SEED, r);
+ UNSAFE.putLong(t, SEED, seed);
UNSAFE.putInt(t, PROBE, probe);
}
@@ -191,124 +220,264 @@
throw new UnsupportedOperationException();
}
- protected int next(int bits) {
+ final long nextSeed() {
Thread t; long r; // read and update per-thread seed
- UNSAFE.putLong
- (t = Thread.currentThread(), SEED,
- r = (UNSAFE.getLong(t, SEED) * multiplier + addend) & mask);
- return (int) (r >>> (48-bits));
+ 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;
}
/**
- * Returns a pseudorandom, uniformly distributed value between the
- * given least value (inclusive) and bound (exclusive).
+ * 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 least the least value returned
- * @param bound the upper bound (exclusive)
- * @throws IllegalArgumentException if least greater than or equal
- * to bound
- * @return the next value
+ * @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(int least, int bound) {
- if (least >= bound)
- throw new IllegalArgumentException();
- return nextInt(bound - least) + least;
+ 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, uniformly distributed value
- * between 0 (inclusive) and the specified value (exclusive).
+ * Returns a pseudorandom {@code int} value between the specified
+ * origin (inclusive) and the specified bound (exclusive).
*
- * @param n the bound on the random number to be returned. Must be
- * positive.
- * @return the next value
- * @throws IllegalArgumentException if n is not positive
+ * @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 long nextLong(long n) {
- if (n <= 0)
- throw new IllegalArgumentException("n must be positive");
- // Divide n by two until small enough for nextInt. On each
- // iteration (at most 31 of them but usually much less),
- // randomly choose both whether to include high bit in result
- // (offset) and whether to continue with the lower vs upper
- // half (which makes a difference only if odd).
- long offset = 0;
- while (n >= Integer.MAX_VALUE) {
- int bits = next(2);
- long half = n >>> 1;
- long nextn = ((bits & 2) == 0) ? half : n - half;
- if ((bits & 1) == 0)
- offset += n - nextn;
- n = nextn;
- }
- return offset + nextInt((int) n);
+ public int nextInt(int origin, int bound) {
+ if (origin >= bound)
+ throw new IllegalArgumentException(BadRange);
+ return internalNextInt(origin, bound);
}
- @Override
- public IntStream ints() {
- return IntStream.generate(() -> current().nextInt());
+ /**
+ * Returns a pseudorandom {@code long} value.
+ *
+ * @return a pseudorandom {@code long} value
+ */
+ public long nextLong() {
+ return mix64(nextSeed());
}
- @Override
- public LongStream longs() {
- return LongStream.generate(() -> current().nextLong());
- }
-
- @Override
- public DoubleStream doubles() {
- return DoubleStream.generate(() -> current().nextDouble());
- }
-
- @Override
- public DoubleStream gaussians() {
- return DoubleStream.generate(() -> current().nextGaussian());
+ /**
+ * 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, uniformly distributed value between the
- * given least value (inclusive) and bound (exclusive).
+ * Returns a pseudorandom {@code long} value between the specified
+ * origin (inclusive) and the specified bound (exclusive).
*
- * @param least the least value returned
+ * @param origin the least value returned
* @param bound the upper bound (exclusive)
- * @return the next value
- * @throws IllegalArgumentException if least greater than or equal
- * to bound
+ * @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 least, long bound) {
- if (least >= bound)
- throw new IllegalArgumentException();
- return nextLong(bound - least) + least;
+ 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, uniformly distributed {@code double} value
- * between 0 (inclusive) and the specified value (exclusive).
+ * Returns a pseudorandom {@code double} value between 0.0
+ * (inclusive) and the specified bound (exclusive).
*
- * @param n the bound on the random number to be returned. Must be
- * positive.
- * @return the next value
- * @throws IllegalArgumentException if n is not positive
+ * @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 n) {
- if (n <= 0)
- throw new IllegalArgumentException("n must be positive");
- return nextDouble() * n;
+ 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, uniformly distributed value between the
- * given least value (inclusive) and bound (exclusive).
+ * Returns a pseudorandom {@code double} value between the specified
+ * origin (inclusive) and bound (exclusive).
*
- * @param least the least value returned
+ * @param origin the least value returned
* @param bound the upper bound (exclusive)
- * @return the next value
- * @throws IllegalArgumentException if least greater than or equal
- * to bound
+ * @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 least, double bound) {
- if (least >= bound)
- throw new IllegalArgumentException();
- return nextDouble() * (bound - least) + least;
+ 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() {
@@ -329,6 +498,445 @@
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
/*
@@ -401,23 +1009,26 @@
*/
private static final ObjectStreamField[] serialPersistentFields = {
new ObjectStreamField("rnd", long.class),
- new ObjectStreamField("initialized", boolean.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 out)
+ private void writeObject(java.io.ObjectOutputStream s)
throws java.io.IOException {
- java.io.ObjectOutputStream.PutField fields = out.putFields();
+ java.io.ObjectOutputStream.PutField fields = s.putFields();
fields.put("rnd", UNSAFE.getLong(Thread.currentThread(), SEED));
fields.put("initialized", true);
- out.writeFields();
+ 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();