--- jsr166/src/main/java/util/SplittableRandom.java 2013/07/11 03:31:26 1.3
+++ jsr166/src/main/java/util/SplittableRandom.java 2013/07/21 14:02:23 1.12
@@ -25,6 +25,7 @@
package java.util;
+import java.security.SecureRandom;
import java.util.concurrent.atomic.AtomicLong;
import java.util.Spliterator;
import java.util.function.IntConsumer;
@@ -35,14 +36,15 @@ import java.util.stream.IntStream;
import java.util.stream.LongStream;
import java.util.stream.DoubleStream;
-
/**
* 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 {@code int}, {@code long},
* and {@code double} with similar usages as for class
- * {@link java.util.Random} but differs in the following ways:
+ * {@link java.util.Random} but differs in the following ways:
+ *
+ *
*
* - Series of generated values pass the DieHarder suite testing
* independence and uniformity properties of random number generators.
@@ -50,12 +52,14 @@ import java.util.stream.DoubleStream;
* href="http://www.phy.duke.edu/~rgb/General/dieharder.php"> 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.
+ * least approximately, for others as well. The period
+ * (length of any series of generated values before it repeats) is at
+ * least 264.
*
* - 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 set of
- * values collectively generated by the two objects has the same
+ * 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.
@@ -97,11 +101,12 @@ public class SplittableRandom {
* Random-Number Generation for Dynamic-Multithreading Platforms",
* PPoPP 2012, but improves and extends it in several ways.
*
- * The primary update step is simply to add a constant ("gamma")
- * to the current seed, modulo a prime ("George"). However, the
- * nextLong and nextInt methods do not return this value, but
- * instead the results of bit-mixing transformations that produce
- * more uniformly distributed sequences.
+ * The primary update step (see method nextSeed()) is simply to
+ * add a constant ("gamma") to the current seed, modulo a prime
+ * ("George"). However, the nextLong and nextInt methods do not
+ * return this value, but instead the results of bit-mixing
+ * transformations that produce more uniformly distributed
+ * sequences.
*
* "George" is the otherwise nameless (because it cannot be
* represented) prime number 2^64+13. Using a prime number larger
@@ -117,18 +122,10 @@ public class SplittableRandom {
* this generator as nextSplit, and uses mix64(nextSplit) as its
* own gamma value. Computations of gammas themselves use a fixed
* constant as the second argument to the addGammaModGeorge
- * function, GAMMA_GAMMA, a "genuinely random" number from a
- * radioactive decay reading (obtained from
- * http://www.fourmilab.ch/hotbits/) meeting the above range
- * constraint. Using a fixed constant maintains the invariant that
- * the value of gamma is the same for every instance that is at
- * the same split-distance from their common root. (Note: there is
- * nothing especially magic about obtaining this constant from a
- * "truly random" physical source rather than just choosing one
- * arbitrarily; using "hotbits" was merely an aesthetically pleasing
- * choice. In either case, good statistical behavior of the
- * algorithm should be, and was, verified by using the DieHarder
- * test suite.)
+ * function, GAMMA_GAMMA. The value of GAMMA_GAMMA is arbitrary
+ * (except must be at least 13), but because it serves as the base
+ * of split sequences, should be subject to validation of
+ * consequent random number quality metrics.
*
* The mix64 bit-mixing function called by nextLong and other
* methods computes the same value as the "64-bit finalizer"
@@ -154,8 +151,8 @@ public class SplittableRandom {
* SplittableRandom. Unlike other cases, this split must be
* performed in a thread-safe manner. We use
* AtomicLong.compareAndSet as the (typically) most efficient
- * mechanism. To bootstrap, we start off using System.nanotime(),
- * and update using another "genuinely random" constant
+ * mechanism. To bootstrap, we start off using a SecureRandom
+ * initial default seed, and update using a fixed
* DEFAULT_SEED_GAMMA. The default constructor uses GAMMA_GAMMA,
* not 0, for its splitSeed argument (addGammaModGeorge(0,
* GAMMA_GAMMA) == GAMMA_GAMMA) to reflect that each is split from
@@ -164,24 +161,35 @@ public class SplittableRandom {
*/
/**
- * The "genuinely random" value for producing new gamma values.
- * The value is arbitrary, subject to the requirement that it be
- * greater or equal to 13.
+ * The value for producing new gamma values. Must be greater or
+ * equal to 13. Otherwise, the value is arbitrary subject to
+ * validation of the resulting statistical quality of splits.
*/
private static final long GAMMA_GAMMA = 0xF2281E2DBA6606F3L;
/**
- * The "genuinely random" seed update value for default constructors.
- * The value is arbitrary, subject to the requirement that it be
- * greater or equal to 13.
+ * The seed update value for default constructors. Must be
+ * greater or equal to 13. Otherwise, the value is arbitrary.
*/
private static final long DEFAULT_SEED_GAMMA = 0xBD24B73A95FB84D9L;
/**
+ * The value 13 with 64bit sign bit set. Used in the signed
+ * comparison in addGammaModGeorge.
+ */
+ private static final long BOTTOM13 = 0x800000000000000DL;
+
+ /**
+ * 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 = 1.0 / (1L << 53);
+
+ /**
* The next seed for default constructors.
*/
private static final AtomicLong defaultSeedGenerator =
- new AtomicLong(System.nanoTime());
+ new AtomicLong(getInitialDefaultSeed());
/**
* The seed, updated only via method nextSeed.
@@ -200,23 +208,6 @@ public class SplittableRandom {
private final long nextSplit;
/**
- * Internal constructor used by all other constructors and by
- * method split. Establishes the initial seed for this instance,
- * and uses the given splitSeed to establish gamma, as well as the
- * nextSplit to use by this instance.
- */
- private SplittableRandom(long seed, long splitSeed) {
- this.seed = seed;
- long s = splitSeed, g;
- do { // ensure gamma >= 13, considered as an unsigned integer
- s = addGammaModGeorge(s, GAMMA_GAMMA);
- g = mix64(s);
- } while (Long.compareUnsigned(g, 13L) < 0);
- this.gamma = g;
- this.nextSplit = s;
- }
-
- /**
* Adds the given gamma value, g, to the given seed value s, mod
* George (2^64+13). We regard s and g as unsigned values
* (ranging from 0 to 2^64-1). We add g to s either once or twice
@@ -226,23 +217,16 @@ public class SplittableRandom {
* George < 2^64; thus we need only a conditional, not a loop,
* to be sure of getting a representable value.
*
- * @param s a seed value
+ * Because Java comparison operators are signed, we implement this
+ * by conceptually offsetting seed values downwards by 2^63, so
+ * 0..13 is represented as Long.MIN_VALUE..BOTTOM13.
+ *
+ * @param s a seed value, viewed as a signed long
* @param g a gamma value, 13 <= g (as unsigned)
*/
private static long addGammaModGeorge(long s, long g) {
long p = s + g;
- if (Long.compareUnsigned(p, g) >= 0)
- return p;
- long q = p - 13L;
- return (Long.compareUnsigned(p, 13L) >= 0) ? q : (q + g);
- }
-
- /**
- * Updates in-place and returns seed.
- * See above for explanation.
- */
- private long nextSeed() {
- return seed = addGammaModGeorge(seed, gamma);
+ return (p >= s) ? p : ((p >= BOTTOM13) ? p : p + g) - 13L;
}
/**
@@ -269,7 +253,33 @@ public class SplittableRandom {
}
/**
- * Atomically updates and returns next seed for default constructor
+ * Internal constructor used by all other constructors and by
+ * method split. Establishes the initial seed for this instance,
+ * and uses the given splitSeed to establish gamma, as well as the
+ * nextSplit to use by this instance. The loop to skip ineligible
+ * gammas very rarely iterates, and does so at most 13 times.
+ */
+ private SplittableRandom(long seed, long splitSeed) {
+ this.seed = seed;
+ long s = splitSeed, g;
+ do { // ensure gamma >= 13, considered as an unsigned integer
+ s = addGammaModGeorge(s, GAMMA_GAMMA);
+ g = mix64(s);
+ } while (g >= 0L && g < 13L);
+ this.gamma = g;
+ this.nextSplit = s;
+ }
+
+ /**
+ * Updates in-place and returns seed.
+ * See above for explanation.
+ */
+ private long nextSeed() {
+ return seed = addGammaModGeorge(seed, gamma);
+ }
+
+ /**
+ * Atomically updates and returns next seed for default constructor.
*/
private static long nextDefaultSeed() {
long oldSeed, newSeed;
@@ -280,6 +290,17 @@ public class SplittableRandom {
return mix64(newSeed);
}
+ /**
+ * Returns an initial default seed.
+ */
+ private static long getInitialDefaultSeed() {
+ 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;
+ }
+
/*
* Internal versions of nextX methods used by streams, as well as
* the public nextX(origin, bound) methods. These exist mainly to
@@ -311,27 +332,31 @@ public class SplittableRandom {
* 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.
+ * 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. Repeatedly generate unbounded longs until obtaining
- * a candidate meeting constraints (with an expected number of
- * iterations of less than two).
+ * 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
+ if ((n & m) == 0L) // power of two
r = (r & m) + origin;
- else if (n > 0) { // reject over-represented candidates
+ else if (n > 0L) { // reject over-represented candidates
for (long u = r >>> 1; // ensure nonnegative
- u + m - (r = u % n) < 0L; // reject
+ u + m - (r = u % n) < 0L; // rejection check
u = mix64(nextSeed()) >>> 1) // retry
;
r += origin;
}
- else { // range not representable as long
+ else { // range not representable as long
while (r < origin || r >= bound)
r = mix64(nextSeed());
}
@@ -355,7 +380,7 @@ public class SplittableRandom {
r = (r & m) + origin;
else if (n > 0) {
for (int u = r >>> 1;
- u + m - (r = u % n) < 0L;
+ u + m - (r = u % n) < 0;
u = mix32(nextSeed()) >>> 1)
;
r += origin;
@@ -376,11 +401,10 @@ public class SplittableRandom {
* @return a pseudorandom value
*/
final double internalNextDouble(double origin, double bound) {
- long bits = (1023L << 52) | (nextLong() >>> 12);
- double r = Double.longBitsToDouble(bits) - 1.0;
+ double r = (nextLong() >>> 11) * DOUBLE_UNIT;
if (origin < bound) {
r = r * (bound - origin) + origin;
- if (r == bound) // correct for rounding
+ if (r >= bound) // correct for rounding
r = Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
}
return r;
@@ -389,9 +413,9 @@ public class SplittableRandom {
/* ---------------- public methods ---------------- */
/**
- * Creates a new SplittableRandom instance using the given initial
- * seed. Two SplittableRandom instances created with the same seed
- * generate identical sequences of values.
+ * 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
*/
@@ -430,21 +454,21 @@ public class SplittableRandom {
/**
* Returns a pseudorandom {@code int} value.
*
- * @return a pseudorandom value
+ * @return a pseudorandom {@code int} value
*/
public int nextInt() {
return mix32(nextSeed());
}
/**
- * Returns a pseudorandom {@code int} value between 0 (inclusive)
+ * Returns a pseudorandom {@code int} value between zero (inclusive)
* and the specified bound (exclusive).
*
* @param bound the bound on the random number to be returned. Must be
* positive.
- * @return a pseudorandom {@code int} value between {@code 0}
- * (inclusive) and the bound (exclusive).
- * @exception IllegalArgumentException if the bound is not positive
+ * @return a pseudorandom {@code int} value between zero
+ * (inclusive) and the bound (exclusive)
+ * @throws IllegalArgumentException if the bound is less than zero
*/
public int nextInt(int bound) {
if (bound <= 0)
@@ -456,7 +480,7 @@ public class SplittableRandom {
r &= m;
else { // reject over-represented candidates
for (int u = r >>> 1;
- u + m - (r = u % bound) < 0L;
+ u + m - (r = u % bound) < 0;
u = mix32(nextSeed()) >>> 1)
;
}
@@ -470,8 +494,8 @@ public class SplittableRandom {
* @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).
- * @exception IllegalArgumentException if {@code origin} is greater than
+ * (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) {
@@ -483,21 +507,21 @@ public class SplittableRandom {
/**
* Returns a pseudorandom {@code long} value.
*
- * @return a pseudorandom value
+ * @return a pseudorandom {@code long} value
*/
public long nextLong() {
return mix64(nextSeed());
}
/**
- * Returns a pseudorandom {@code long} value between 0 (inclusive)
+ * Returns a pseudorandom {@code long} value between zero (inclusive)
* and the specified bound (exclusive).
*
* @param bound the bound on the random number to be returned. Must be
* positive.
- * @return a pseudorandom {@code long} value between {@code 0}
- * (inclusive) and the bound (exclusive).
- * @exception IllegalArgumentException if the bound is not positive
+ * @return a pseudorandom {@code long} value between zero
+ * (inclusive) and the bound (exclusive)
+ * @throws IllegalArgumentException if {@code bound} is less than zero
*/
public long nextLong(long bound) {
if (bound <= 0)
@@ -523,8 +547,8 @@ public class SplittableRandom {
* @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).
- * @exception IllegalArgumentException if {@code origin} is greater than
+ * (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) {
@@ -534,15 +558,14 @@ public class SplittableRandom {
}
/**
- * Returns a pseudorandom {@code double} value between {@code 0.0}
- * (inclusive) and {@code 1.0} (exclusive).
+ * Returns a pseudorandom {@code double} value between zero
+ * (inclusive) and one (exclusive).
*
- * @return a pseudorandom value between {@code 0.0}
- * (inclusive) and {@code 1.0} (exclusive)
+ * @return a pseudorandom {@code double} value between zero
+ * (inclusive) and one (exclusive)
*/
public double nextDouble() {
- long bits = (1023L << 52) | (nextLong() >>> 12);
- return Double.longBitsToDouble(bits) - 1.0;
+ return (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT;
}
/**
@@ -551,46 +574,55 @@ public class SplittableRandom {
*
* @param bound the bound on the random number to be returned. Must be
* positive.
- * @return a pseudorandom {@code double} value between {@code 0.0}
- * (inclusive) and the bound (exclusive).
- * @throws IllegalArgumentException if {@code bound} is not positive
+ * @return a pseudorandom {@code double} value between zero
+ * (inclusive) and the bound (exclusive)
+ * @throws IllegalArgumentException if {@code bound} is less than zero
*/
public double nextDouble(double bound) {
- if (bound <= 0.0)
+ if (!(bound > 0.0))
throw new IllegalArgumentException("bound must be positive");
- double result = nextDouble() * 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 {@code double} value between the given
+ * 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
* @return a pseudorandom {@code double} value between the origin
- * (inclusive) and the bound (exclusive).
+ * (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)
+ if (!(origin < bound))
throw new IllegalArgumentException("bound must be greater than origin");
return internalNextDouble(origin, bound);
}
+ /**
+ * 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 with the given {@code streamSize} number of
+ * 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
+ * less than zero
*/
public IntStream ints(long streamSize) {
if (streamSize < 0L)
@@ -603,7 +635,7 @@ public class SplittableRandom {
/**
* Returns an effectively unlimited stream of pseudorandom {@code int}
- * values
+ * values.
*
* @implNote This method is implemented to be equivalent to {@code
* ints(Long.MAX_VALUE)}.
@@ -618,7 +650,7 @@ public class SplittableRandom {
}
/**
- * Returns a stream with the given {@code streamSize} number of
+ * Returns a stream producing the given {@code streamSize} number of
* pseudorandom {@code int} values, each conforming to the given
* origin and bound.
*
@@ -626,10 +658,9 @@ public class SplittableRandom {
* @param randomNumberOrigin the origin of each random value
* @param randomNumberBound the bound of each random value
* @return a stream of pseudorandom {@code int} values,
- * each with the given origin and bound.
+ * each with the given origin and bound
* @throws IllegalArgumentException if {@code streamSize} is
- * less than zero.
- * @throws IllegalArgumentException if {@code randomNumberOrigin}
+ * less than zero, or {@code randomNumberOrigin}
* is greater than or equal to {@code randomNumberBound}
*/
public IntStream ints(long streamSize, int randomNumberOrigin,
@@ -654,7 +685,7 @@ public class SplittableRandom {
* @param randomNumberOrigin the origin of each random value
* @param randomNumberBound the bound of each random value
* @return a stream of pseudorandom {@code int} values,
- * each with the given origin and bound.
+ * each with the given origin and bound
* @throws IllegalArgumentException if {@code randomNumberOrigin}
* is greater than or equal to {@code randomNumberBound}
*/
@@ -668,13 +699,13 @@ public class SplittableRandom {
}
/**
- * Returns a stream with the given {@code streamSize} number of
+ * 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 {@code long} values
+ * @return a stream of pseudorandom {@code long} values
* @throws IllegalArgumentException if {@code streamSize} is
- * less than zero
+ * less than zero
*/
public LongStream longs(long streamSize) {
if (streamSize < 0L)
@@ -702,7 +733,7 @@ public class SplittableRandom {
}
/**
- * Returns a stream with the given {@code streamSize} number of
+ * Returns a stream producing the given {@code streamSize} number of
* pseudorandom {@code long} values, each conforming to the
* given origin and bound.
*
@@ -710,10 +741,9 @@ public class SplittableRandom {
* @param randomNumberOrigin the origin of each random value
* @param randomNumberBound the bound of each random value
* @return a stream of pseudorandom {@code long} values,
- * each with the given origin and bound.
+ * each with the given origin and bound
* @throws IllegalArgumentException if {@code streamSize} is
- * less than zero.
- * @throws IllegalArgumentException if {@code randomNumberOrigin}
+ * less than zero, or {@code randomNumberOrigin}
* is greater than or equal to {@code randomNumberBound}
*/
public LongStream longs(long streamSize, long randomNumberOrigin,
@@ -738,7 +768,7 @@ public class SplittableRandom {
* @param randomNumberOrigin the origin of each random value
* @param randomNumberBound the bound of each random value
* @return a stream of pseudorandom {@code long} values,
- * each with the given origin and bound.
+ * each with the given origin and bound
* @throws IllegalArgumentException if {@code randomNumberOrigin}
* is greater than or equal to {@code randomNumberBound}
*/
@@ -752,14 +782,14 @@ public class SplittableRandom {
}
/**
- * Returns a stream with the given {@code streamSize} number of
- * pseudorandom {@code double} values, each between {@code 0.0}
- * (inclusive) and {@code 1.0} (exclusive).
+ * 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
+ * less than zero
*/
public DoubleStream doubles(long streamSize) {
if (streamSize < 0L)
@@ -772,8 +802,8 @@ public class SplittableRandom {
/**
* Returns an effectively unlimited stream of pseudorandom {@code
- * double} values, each between {@code 0.0} (inclusive) and {@code
- * 1.0} (exclusive).
+ * double} values, each between zero (inclusive) and one
+ * (exclusive).
*
* @implNote This method is implemented to be equivalent to {@code
* doubles(Long.MAX_VALUE)}.
@@ -788,7 +818,7 @@ public class SplittableRandom {
}
/**
- * Returns a stream with the given {@code streamSize} number of
+ * Returns a stream producing the given {@code streamSize} number of
* pseudorandom {@code double} values, each conforming to the
* given origin and bound.
*
@@ -796,9 +826,9 @@ public class SplittableRandom {
* @param randomNumberOrigin the origin of each random value
* @param randomNumberBound the bound of each random value
* @return a stream of pseudorandom {@code double} values,
- * each with the given origin and bound.
+ * each with the given origin and bound
* @throws IllegalArgumentException if {@code streamSize} is
- * less than zero.
+ * less than zero
* @throws IllegalArgumentException if {@code randomNumberOrigin}
* is greater than or equal to {@code randomNumberBound}
*/
@@ -806,7 +836,7 @@ public class SplittableRandom {
double randomNumberBound) {
if (streamSize < 0L)
throw new IllegalArgumentException("negative Stream size");
- if (randomNumberOrigin >= randomNumberBound)
+ if (!(randomNumberOrigin < randomNumberBound))
throw new IllegalArgumentException("bound must be greater than origin");
return StreamSupport.doubleStream
(new RandomDoublesSpliterator
@@ -824,12 +854,12 @@ public class SplittableRandom {
* @param randomNumberOrigin the origin of each random value
* @param randomNumberBound the bound of each random value
* @return a stream of pseudorandom {@code double} values,
- * each with the given origin and bound.
+ * each with the given origin and bound
* @throws IllegalArgumentException if {@code randomNumberOrigin}
* is greater than or equal to {@code randomNumberBound}
*/
public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
- if (randomNumberOrigin >= randomNumberBound)
+ if (!(randomNumberOrigin < randomNumberBound))
throw new IllegalArgumentException("bound must be greater than origin");
return StreamSupport.doubleStream
(new RandomDoublesSpliterator
@@ -839,13 +869,13 @@ public class SplittableRandom {
/**
* Spliterator for int streams. We multiplex the four int
- * versions into one class by treating and bound < origin as
+ * 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 class RandomIntsSpliterator implements Spliterator.OfInt {
+ static final class RandomIntsSpliterator implements Spliterator.OfInt {
final SplittableRandom rng;
long index;
final long fence;
@@ -869,8 +899,7 @@ public class SplittableRandom {
public int characteristics() {
return (Spliterator.SIZED | Spliterator.SUBSIZED |
- Spliterator.ORDERED | Spliterator.NONNULL |
- Spliterator.IMMUTABLE);
+ Spliterator.NONNULL | Spliterator.IMMUTABLE);
}
public boolean tryAdvance(IntConsumer consumer) {
@@ -900,7 +929,7 @@ public class SplittableRandom {
/**
* Spliterator for long streams.
*/
- static class RandomLongsSpliterator implements Spliterator.OfLong {
+ static final class RandomLongsSpliterator implements Spliterator.OfLong {
final SplittableRandom rng;
long index;
final long fence;
@@ -924,8 +953,7 @@ public class SplittableRandom {
public int characteristics() {
return (Spliterator.SIZED | Spliterator.SUBSIZED |
- Spliterator.ORDERED | Spliterator.NONNULL |
- Spliterator.IMMUTABLE);
+ Spliterator.NONNULL | Spliterator.IMMUTABLE);
}
public boolean tryAdvance(LongConsumer consumer) {
@@ -956,7 +984,7 @@ public class SplittableRandom {
/**
* Spliterator for double streams.
*/
- static class RandomDoublesSpliterator implements Spliterator.OfDouble {
+ static final class RandomDoublesSpliterator implements Spliterator.OfDouble {
final SplittableRandom rng;
long index;
final long fence;
@@ -980,8 +1008,7 @@ public class SplittableRandom {
public int characteristics() {
return (Spliterator.SIZED | Spliterator.SUBSIZED |
- Spliterator.ORDERED | Spliterator.NONNULL |
- Spliterator.IMMUTABLE);
+ Spliterator.NONNULL | Spliterator.IMMUTABLE);
}
public boolean tryAdvance(DoubleConsumer consumer) {
@@ -1009,4 +1036,3 @@ public class SplittableRandom {
}
}
-