52 |
|
* types and ranges, but similar properties are expected to hold, at |
53 |
|
* least approximately, for others as well. The <em>period</em> |
54 |
|
* (length of any series of generated values before it repeats) is at |
55 |
< |
* least 2<sup>64</sup>. </li> |
55 |
> |
* least 2<sup>64</sup>. |
56 |
|
* |
57 |
< |
* <li> Method {@link #split} constructs and returns a new |
57 |
> |
* <li>Method {@link #split} constructs and returns a new |
58 |
|
* SplittableRandom instance that shares no mutable state with the |
59 |
|
* current instance. However, with very high probability, the |
60 |
|
* values collectively generated by the two objects have the same |
61 |
|
* statistical properties as if the same quantity of values were |
62 |
|
* generated by a single thread using a single {@code |
63 |
< |
* SplittableRandom} object. </li> |
63 |
> |
* SplittableRandom} object. |
64 |
|
* |
65 |
|
* <li>Instances of SplittableRandom are <em>not</em> thread-safe. |
66 |
|
* They are designed to be split, not shared, across threads. For |
71 |
|
* |
72 |
|
* <li>This class provides additional methods for generating random |
73 |
|
* streams, that employ the above techniques when used in {@code |
74 |
< |
* stream.parallel()} mode.</li> |
74 |
> |
* stream.parallel()} mode. |
75 |
|
* |
76 |
|
* </ul> |
77 |
|
* |
219 |
|
return seed += gamma; |
220 |
|
} |
221 |
|
|
222 |
+ |
// IllegalArgumentException messages |
223 |
+ |
static final String BAD_BOUND = "bound must be positive"; |
224 |
+ |
static final String BAD_RANGE = "bound must be greater than origin"; |
225 |
+ |
static final String BAD_SIZE = "size must be non-negative"; |
226 |
+ |
|
227 |
|
/** |
228 |
|
* The seed generator for default constructors. |
229 |
|
*/ |
230 |
< |
private static final AtomicLong defaultGen = new AtomicLong(initialSeed()); |
231 |
< |
|
232 |
< |
private static long initialSeed() { |
233 |
< |
String pp = java.security.AccessController.doPrivileged( |
234 |
< |
new sun.security.action.GetPropertyAction( |
235 |
< |
"java.util.secureRandomSeed")); |
236 |
< |
if (pp != null && pp.equalsIgnoreCase("true")) { |
230 |
> |
private static final AtomicLong defaultGen |
231 |
> |
= new AtomicLong(mix64(System.currentTimeMillis()) ^ |
232 |
> |
mix64(System.nanoTime())); |
233 |
> |
|
234 |
> |
// at end of <clinit> to survive static initialization circularity |
235 |
> |
static { |
236 |
> |
if (java.security.AccessController.doPrivileged( |
237 |
> |
new java.security.PrivilegedAction<Boolean>() { |
238 |
> |
public Boolean run() { |
239 |
> |
return Boolean.getBoolean("java.util.secureRandomSeed"); |
240 |
> |
}})) { |
241 |
|
byte[] seedBytes = java.security.SecureRandom.getSeed(8); |
242 |
< |
long s = (long)(seedBytes[0]) & 0xffL; |
242 |
> |
long s = (long)seedBytes[0] & 0xffL; |
243 |
|
for (int i = 1; i < 8; ++i) |
244 |
< |
s = (s << 8) | ((long)(seedBytes[i]) & 0xffL); |
245 |
< |
return s; |
244 |
> |
s = (s << 8) | ((long)seedBytes[i] & 0xffL); |
245 |
> |
defaultGen.set(s); |
246 |
|
} |
238 |
– |
return (mix64(System.currentTimeMillis()) ^ |
239 |
– |
mix64(System.nanoTime())); |
247 |
|
} |
248 |
|
|
242 |
– |
// IllegalArgumentException messages |
243 |
– |
static final String BadBound = "bound must be positive"; |
244 |
– |
static final String BadRange = "bound must be greater than origin"; |
245 |
– |
static final String BadSize = "size must be non-negative"; |
246 |
– |
|
249 |
|
/* |
250 |
|
* Internal versions of nextX methods used by streams, as well as |
251 |
|
* the public nextX(origin, bound) methods. These exist mainly to |
418 |
|
*/ |
419 |
|
public int nextInt(int bound) { |
420 |
|
if (bound <= 0) |
421 |
< |
throw new IllegalArgumentException(BadBound); |
421 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
422 |
|
// Specialize internalNextInt for origin 0 |
423 |
|
int r = mix32(nextSeed()); |
424 |
|
int m = bound - 1; |
446 |
|
*/ |
447 |
|
public int nextInt(int origin, int bound) { |
448 |
|
if (origin >= bound) |
449 |
< |
throw new IllegalArgumentException(BadRange); |
449 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
450 |
|
return internalNextInt(origin, bound); |
451 |
|
} |
452 |
|
|
470 |
|
*/ |
471 |
|
public long nextLong(long bound) { |
472 |
|
if (bound <= 0) |
473 |
< |
throw new IllegalArgumentException(BadBound); |
473 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
474 |
|
// Specialize internalNextLong for origin 0 |
475 |
|
long r = mix64(nextSeed()); |
476 |
|
long m = bound - 1; |
498 |
|
*/ |
499 |
|
public long nextLong(long origin, long bound) { |
500 |
|
if (origin >= bound) |
501 |
< |
throw new IllegalArgumentException(BadRange); |
501 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
502 |
|
return internalNextLong(origin, bound); |
503 |
|
} |
504 |
|
|
524 |
|
*/ |
525 |
|
public double nextDouble(double bound) { |
526 |
|
if (!(bound > 0.0)) |
527 |
< |
throw new IllegalArgumentException(BadBound); |
527 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
528 |
|
double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound; |
529 |
|
return (result < bound) ? result : // correct for rounding |
530 |
|
Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1); |
531 |
|
} |
532 |
|
|
533 |
|
/** |
534 |
+ |
* Generates a pseudorandom number with the indicated number of |
535 |
+ |
* bits. Unlike in superclass @{link Random}, this method is never |
536 |
+ |
* internally called or used by any other publicly accessible |
537 |
+ |
* method. |
538 |
+ |
* |
539 |
+ |
* @param bits random bits |
540 |
+ |
* @return the next pseudorandom value from this random number |
541 |
+ |
* generator's sequence |
542 |
+ |
*/ |
543 |
+ |
protected int next(int bits) { |
544 |
+ |
return (int)(nextLong() >>> (64 - bits)); |
545 |
+ |
} |
546 |
+ |
|
547 |
+ |
/** |
548 |
|
* Returns a pseudorandom {@code double} value between the specified |
549 |
|
* origin (inclusive) and bound (exclusive). |
550 |
|
* |
557 |
|
*/ |
558 |
|
public double nextDouble(double origin, double bound) { |
559 |
|
if (!(origin < bound)) |
560 |
< |
throw new IllegalArgumentException(BadRange); |
560 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
561 |
|
return internalNextDouble(origin, bound); |
562 |
|
} |
563 |
|
|
585 |
|
*/ |
586 |
|
public IntStream ints(long streamSize) { |
587 |
|
if (streamSize < 0L) |
588 |
< |
throw new IllegalArgumentException(BadSize); |
588 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
589 |
|
return StreamSupport.intStream |
590 |
|
(new RandomIntsSpliterator |
591 |
|
(this, 0L, streamSize, Integer.MAX_VALUE, 0), |
626 |
|
public IntStream ints(long streamSize, int randomNumberOrigin, |
627 |
|
int randomNumberBound) { |
628 |
|
if (streamSize < 0L) |
629 |
< |
throw new IllegalArgumentException(BadSize); |
629 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
630 |
|
if (randomNumberOrigin >= randomNumberBound) |
631 |
< |
throw new IllegalArgumentException(BadRange); |
631 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
632 |
|
return StreamSupport.intStream |
633 |
|
(new RandomIntsSpliterator |
634 |
|
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound), |
652 |
|
*/ |
653 |
|
public IntStream ints(int randomNumberOrigin, int randomNumberBound) { |
654 |
|
if (randomNumberOrigin >= randomNumberBound) |
655 |
< |
throw new IllegalArgumentException(BadRange); |
655 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
656 |
|
return StreamSupport.intStream |
657 |
|
(new RandomIntsSpliterator |
658 |
|
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
671 |
|
*/ |
672 |
|
public LongStream longs(long streamSize) { |
673 |
|
if (streamSize < 0L) |
674 |
< |
throw new IllegalArgumentException(BadSize); |
674 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
675 |
|
return StreamSupport.longStream |
676 |
|
(new RandomLongsSpliterator |
677 |
|
(this, 0L, streamSize, Long.MAX_VALUE, 0L), |
712 |
|
public LongStream longs(long streamSize, long randomNumberOrigin, |
713 |
|
long randomNumberBound) { |
714 |
|
if (streamSize < 0L) |
715 |
< |
throw new IllegalArgumentException(BadSize); |
715 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
716 |
|
if (randomNumberOrigin >= randomNumberBound) |
717 |
< |
throw new IllegalArgumentException(BadRange); |
717 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
718 |
|
return StreamSupport.longStream |
719 |
|
(new RandomLongsSpliterator |
720 |
|
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound), |
738 |
|
*/ |
739 |
|
public LongStream longs(long randomNumberOrigin, long randomNumberBound) { |
740 |
|
if (randomNumberOrigin >= randomNumberBound) |
741 |
< |
throw new IllegalArgumentException(BadRange); |
741 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
742 |
|
return StreamSupport.longStream |
743 |
|
(new RandomLongsSpliterator |
744 |
|
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
757 |
|
*/ |
758 |
|
public DoubleStream doubles(long streamSize) { |
759 |
|
if (streamSize < 0L) |
760 |
< |
throw new IllegalArgumentException(BadSize); |
760 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
761 |
|
return StreamSupport.doubleStream |
762 |
|
(new RandomDoublesSpliterator |
763 |
|
(this, 0L, streamSize, Double.MAX_VALUE, 0.0), |
800 |
|
public DoubleStream doubles(long streamSize, double randomNumberOrigin, |
801 |
|
double randomNumberBound) { |
802 |
|
if (streamSize < 0L) |
803 |
< |
throw new IllegalArgumentException(BadSize); |
803 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
804 |
|
if (!(randomNumberOrigin < randomNumberBound)) |
805 |
< |
throw new IllegalArgumentException(BadRange); |
805 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
806 |
|
return StreamSupport.doubleStream |
807 |
|
(new RandomDoublesSpliterator |
808 |
|
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound), |
826 |
|
*/ |
827 |
|
public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) { |
828 |
|
if (!(randomNumberOrigin < randomNumberBound)) |
829 |
< |
throw new IllegalArgumentException(BadRange); |
829 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
830 |
|
return StreamSupport.doubleStream |
831 |
|
(new RandomDoublesSpliterator |
832 |
|
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
841 |
|
* approach. The long and double versions of this class are |
842 |
|
* identical except for types. |
843 |
|
*/ |
844 |
< |
static final class RandomIntsSpliterator implements Spliterator.OfInt { |
844 |
> |
private static final class RandomIntsSpliterator |
845 |
> |
implements Spliterator.OfInt { |
846 |
|
final SplittableRandom rng; |
847 |
|
long index; |
848 |
|
final long fence; |
897 |
|
/** |
898 |
|
* Spliterator for long streams. |
899 |
|
*/ |
900 |
< |
static final class RandomLongsSpliterator implements Spliterator.OfLong { |
900 |
> |
private static final class RandomLongsSpliterator |
901 |
> |
implements Spliterator.OfLong { |
902 |
|
final SplittableRandom rng; |
903 |
|
long index; |
904 |
|
final long fence; |
954 |
|
/** |
955 |
|
* Spliterator for double streams. |
956 |
|
*/ |
957 |
< |
static final class RandomDoublesSpliterator implements Spliterator.OfDouble { |
957 |
> |
private static final class RandomDoublesSpliterator |
958 |
> |
implements Spliterator.OfDouble { |
959 |
|
final SplittableRandom rng; |
960 |
|
long index; |
961 |
|
final long fence; |