| 25 |
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|
| 26 |
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package java.util; |
| 27 |
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|
| 28 |
< |
import java.net.InetAddress; |
| 28 |
> |
import java.net.NetworkInterface; |
| 29 |
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import java.util.concurrent.atomic.AtomicLong; |
| 30 |
– |
import java.util.Spliterator; |
| 30 |
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import java.util.function.IntConsumer; |
| 31 |
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import java.util.function.LongConsumer; |
| 32 |
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import java.util.function.DoubleConsumer; |
| 38 |
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/** |
| 39 |
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* A generator of uniform pseudorandom values applicable for use in |
| 40 |
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* (among other contexts) isolated parallel computations that may |
| 41 |
< |
* generate subtasks. Class SplittableRandom supports methods for |
| 41 |
> |
* generate subtasks. Class {@code SplittableRandom} supports methods for |
| 42 |
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* producing pseudorandom numbers of type {@code int}, {@code long}, |
| 43 |
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* and {@code double} with similar usages as for class |
| 44 |
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* {@link java.util.Random} but differs in the following ways: |
| 76 |
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* |
| 77 |
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* </ul> |
| 78 |
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* |
| 79 |
+ |
* <p>Instances of {@code SplittableRandom} are not cryptographically |
| 80 |
+ |
* secure. Consider instead using {@link java.security.SecureRandom} |
| 81 |
+ |
* in security-sensitive applications. Additionally, |
| 82 |
+ |
* default-constructed instances do not use a cryptographically random |
| 83 |
+ |
* seed unless the {@linkplain System#getProperty system property} |
| 84 |
+ |
* {@code java.util.secureRandomSeed} is set to {@code true}. |
| 85 |
+ |
* |
| 86 |
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* @author Guy Steele |
| 87 |
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* @author Doug Lea |
| 88 |
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* @since 1.8 |
| 89 |
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*/ |
| 90 |
< |
public class SplittableRandom { |
| 90 |
> |
public final class SplittableRandom { |
| 91 |
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|
| 92 |
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/* |
| 93 |
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* Implementation Overview. |
| 107 |
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* Methods nextLong, nextInt, and derivatives do not return the |
| 108 |
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* sequence (seed) values, but instead a hash-like bit-mix of |
| 109 |
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* their bits, producing more independently distributed sequences. |
| 110 |
< |
* For nextLong, the mix64 bit-mixing function computes the same |
| 111 |
< |
* value as the "64-bit finalizer" function in Austin Appleby's |
| 112 |
< |
* MurmurHash3 algorithm. See |
| 113 |
< |
* http://code.google.com/p/smhasher/wiki/MurmurHash3 , which |
| 114 |
< |
* comments: "The constants for the finalizers were generated by a |
| 115 |
< |
* simple simulated-annealing algorithm, and both avalanche all |
| 116 |
< |
* bits of 'h' to within 0.25% bias." The mix32 function is |
| 111 |
< |
* equivalent to (int)(mix64(seed) >>> 32), but faster because it |
| 112 |
< |
* omits a step that doesn't contribute to result. |
| 110 |
> |
* For nextLong, the mix64 function is based on David Stafford's |
| 111 |
> |
* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html) |
| 112 |
> |
* "Mix13" variant of the "64-bit finalizer" function in Austin |
| 113 |
> |
* Appleby's MurmurHash3 algorithm (see |
| 114 |
> |
* http://code.google.com/p/smhasher/wiki/MurmurHash3). The mix32 |
| 115 |
> |
* function is based on Stafford's Mix04 mix function, but returns |
| 116 |
> |
* the upper 32 bits cast as int. |
| 117 |
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* |
| 118 |
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* The split operation uses the current generator to form the seed |
| 119 |
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* and gamma for another SplittableRandom. To conservatively |
| 120 |
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* avoid potential correlations between seed and value generation, |
| 121 |
< |
* gamma selection (method nextGamma) uses the "Mix13" constants |
| 122 |
< |
* for MurmurHash3 described by David Stafford |
| 123 |
< |
* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html) |
| 124 |
< |
* To avoid potential weaknesses in bit-mixing transformations, we |
| 125 |
< |
* restrict gammas to odd values with at least 12 and no more than |
| 126 |
< |
* 52 bits set. Rather than rejecting candidates with too few or |
| 127 |
< |
* too many bits set, method nextGamma flips some bits (which has |
| 128 |
< |
* the effect of mapping at most 4 to any given gamma value). |
| 125 |
< |
* This reduces the effective set of 64bit odd gamma values by |
| 126 |
< |
* about 2<sup>14</sup>, a very tiny percentage, and serves as an |
| 121 |
> |
* gamma selection (method mixGamma) uses different |
| 122 |
> |
* (Murmurhash3's) mix constants. To avoid potential weaknesses |
| 123 |
> |
* in bit-mixing transformations, we restrict gammas to odd values |
| 124 |
> |
* with at least 24 0-1 or 1-0 bit transitions. Rather than |
| 125 |
> |
* rejecting candidates with too few or too many bits set, method |
| 126 |
> |
* mixGamma flips some bits (which has the effect of mapping at |
| 127 |
> |
* most 4 to any given gamma value). This reduces the effective |
| 128 |
> |
* set of 64bit odd gamma values by about 2%, and serves as an |
| 129 |
|
* automated screening for sequence constant selection that is |
| 130 |
|
* left as an empirical decision in some other hashing and crypto |
| 131 |
|
* algorithms. |
| 136 |
|
* avalanching. |
| 137 |
|
* |
| 138 |
|
* The default (no-argument) constructor, in essence, invokes |
| 139 |
< |
* split() for a common "seeder" SplittableRandom. Unlike other |
| 140 |
< |
* cases, this split must be performed in a thread-safe manner, so |
| 141 |
< |
* we use an AtomicLong to represent the seed rather than use an |
| 142 |
< |
* explicit SplittableRandom. To bootstrap the seeder, we start |
| 143 |
< |
* off using a seed based on current time and host. This serves as |
| 144 |
< |
* a slimmed-down (and insecure) variant of SecureRandom that also |
| 145 |
< |
* avoids stalls that may occur when using /dev/random. |
| 139 |
> |
* split() for a common "defaultGen" SplittableRandom. Unlike |
| 140 |
> |
* other cases, this split must be performed in a thread-safe |
| 141 |
> |
* manner, so we use an AtomicLong to represent the seed rather |
| 142 |
> |
* than use an explicit SplittableRandom. To bootstrap the |
| 143 |
> |
* defaultGen, we start off using a seed based on current time and |
| 144 |
> |
* network interface address unless the java.util.secureRandomSeed |
| 145 |
> |
* property is set. This serves as a slimmed-down (and insecure) |
| 146 |
> |
* variant of SecureRandom that also avoids stalls that may occur |
| 147 |
> |
* when using /dev/random. |
| 148 |
|
* |
| 149 |
|
* It is a relatively simple matter to apply the basic design here |
| 150 |
|
* to use 128 bit seeds. However, emulating 128bit arithmetic and |
| 157 |
|
*/ |
| 158 |
|
|
| 159 |
|
/** |
| 160 |
< |
* The initial gamma value for (unsplit) SplittableRandoms. Must |
| 161 |
< |
* be odd with at least 12 and no more than 52 bits set. Currently |
| 158 |
< |
* set to the golden ratio scaled to 64bits. |
| 160 |
> |
* The golden ratio scaled to 64bits, used as the initial gamma |
| 161 |
> |
* value for (unsplit) SplittableRandoms. |
| 162 |
|
*/ |
| 163 |
< |
private static final long INITIAL_GAMMA = 0x9e3779b97f4a7c15L; |
| 163 |
> |
private static final long GOLDEN_GAMMA = 0x9e3779b97f4a7c15L; |
| 164 |
|
|
| 165 |
|
/** |
| 166 |
|
* The least non-zero value returned by nextDouble(). This value |
| 167 |
|
* is scaled by a random value of 53 bits to produce a result. |
| 168 |
|
*/ |
| 169 |
< |
private static final double DOUBLE_UNIT = 1.0 / (1L << 53); |
| 169 |
> |
private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53); |
| 170 |
|
|
| 171 |
|
/** |
| 172 |
|
* The seed. Updated only via method nextSeed. |
| 187 |
|
} |
| 188 |
|
|
| 189 |
|
/** |
| 190 |
< |
* Computes MurmurHash3 64bit mix function. |
| 190 |
> |
* Computes Stafford variant 13 of 64bit mix function. |
| 191 |
|
*/ |
| 192 |
|
private static long mix64(long z) { |
| 193 |
< |
z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; |
| 194 |
< |
z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L; |
| 195 |
< |
return z ^ (z >>> 33); |
| 193 |
> |
z = (z ^ (z >>> 30)) * 0xbf58476d1ce4e5b9L; |
| 194 |
> |
z = (z ^ (z >>> 27)) * 0x94d049bb133111ebL; |
| 195 |
> |
return z ^ (z >>> 31); |
| 196 |
|
} |
| 197 |
|
|
| 198 |
|
/** |
| 199 |
< |
* Returns the 32 high bits of mix64(z) as int. |
| 199 |
> |
* Returns the 32 high bits of Stafford variant 4 mix64 function as int. |
| 200 |
|
*/ |
| 201 |
|
private static int mix32(long z) { |
| 202 |
< |
z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; |
| 203 |
< |
return (int)(((z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L) >>> 32); |
| 202 |
> |
z = (z ^ (z >>> 33)) * 0x62a9d9ed799705f5L; |
| 203 |
> |
return (int)(((z ^ (z >>> 28)) * 0xcb24d0a5c88c35b3L) >>> 32); |
| 204 |
|
} |
| 205 |
|
|
| 206 |
|
/** |
| 207 |
|
* Returns the gamma value to use for a new split instance. |
| 208 |
|
*/ |
| 209 |
< |
private static long nextGamma(long z) { |
| 210 |
< |
z = (z ^ (z >>> 30)) * 0xbf58476d1ce4e5b9L; // Stafford "Mix13" |
| 211 |
< |
z = (z ^ (z >>> 27)) * 0x94d049bb133111ebL; |
| 212 |
< |
z = (z ^ (z >>> 31)) | 1L; // force to be odd |
| 213 |
< |
int n = Long.bitCount(z); // ensure enough 0 and 1 bits |
| 214 |
< |
return (n < 12 || n > 52) ? z ^ 0xaaaaaaaaaaaaaaaaL : z; |
| 209 |
> |
private static long mixGamma(long z) { |
| 210 |
> |
z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; // MurmurHash3 mix constants |
| 211 |
> |
z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L; |
| 212 |
> |
z = (z ^ (z >>> 33)) | 1L; // force to be odd |
| 213 |
> |
int n = Long.bitCount(z ^ (z >>> 1)); // ensure enough transitions |
| 214 |
> |
return (n < 24) ? z ^ 0xaaaaaaaaaaaaaaaaL : z; |
| 215 |
|
} |
| 216 |
|
|
| 217 |
|
/** |
| 224 |
|
/** |
| 225 |
|
* The seed generator for default constructors. |
| 226 |
|
*/ |
| 227 |
< |
private static final AtomicLong seeder = |
| 225 |
< |
new AtomicLong(mix64((((long)hashedHostAddress()) << 32) ^ |
| 226 |
< |
System.currentTimeMillis()) ^ |
| 227 |
< |
mix64(System.nanoTime())); |
| 227 |
> |
private static final AtomicLong defaultGen = new AtomicLong(initialSeed()); |
| 228 |
|
|
| 229 |
< |
/** |
| 230 |
< |
* Returns hash of local host IP address, if available; else 0. |
| 231 |
< |
*/ |
| 232 |
< |
private static int hashedHostAddress() { |
| 233 |
< |
try { |
| 234 |
< |
return InetAddress.getLocalHost().hashCode(); |
| 235 |
< |
} catch (Exception ex) { |
| 236 |
< |
return 0; |
| 237 |
< |
} |
| 229 |
> |
private static long initialSeed() { |
| 230 |
> |
String pp = java.security.AccessController.doPrivileged( |
| 231 |
> |
new sun.security.action.GetPropertyAction( |
| 232 |
> |
"java.util.secureRandomSeed")); |
| 233 |
> |
if (pp != null && pp.equalsIgnoreCase("true")) { |
| 234 |
> |
byte[] seedBytes = java.security.SecureRandom.getSeed(8); |
| 235 |
> |
long s = (long)(seedBytes[0]) & 0xffL; |
| 236 |
> |
for (int i = 1; i < 8; ++i) |
| 237 |
> |
s = (s << 8) | ((long)(seedBytes[i]) & 0xffL); |
| 238 |
> |
return s; |
| 239 |
> |
} |
| 240 |
> |
long h = 0L; |
| 241 |
> |
try { |
| 242 |
> |
Enumeration<NetworkInterface> ifcs = |
| 243 |
> |
NetworkInterface.getNetworkInterfaces(); |
| 244 |
> |
boolean retry = false; // retry once if getHardwareAddress is null |
| 245 |
> |
while (ifcs.hasMoreElements()) { |
| 246 |
> |
NetworkInterface ifc = ifcs.nextElement(); |
| 247 |
> |
if (!ifc.isVirtual()) { // skip fake addresses |
| 248 |
> |
byte[] bs = ifc.getHardwareAddress(); |
| 249 |
> |
if (bs != null) { |
| 250 |
> |
int n = bs.length; |
| 251 |
> |
int m = Math.min(n >>> 1, 4); |
| 252 |
> |
for (int i = 0; i < m; ++i) |
| 253 |
> |
h = (h << 16) ^ (bs[i] << 8) ^ bs[n-1-i]; |
| 254 |
> |
if (m < 4) |
| 255 |
> |
h = (h << 8) ^ bs[n-1-m]; |
| 256 |
> |
h = mix64(h); |
| 257 |
> |
break; |
| 258 |
> |
} |
| 259 |
> |
else if (!retry) |
| 260 |
> |
retry = true; |
| 261 |
> |
else |
| 262 |
> |
break; |
| 263 |
> |
} |
| 264 |
> |
} |
| 265 |
> |
} catch (Exception ignore) { |
| 266 |
> |
} |
| 267 |
> |
return (h ^ mix64(System.currentTimeMillis()) ^ |
| 268 |
> |
mix64(System.nanoTime())); |
| 269 |
|
} |
| 270 |
|
|
| 271 |
|
// IllegalArgumentException messages |
| 392 |
|
* @param seed the initial seed |
| 393 |
|
*/ |
| 394 |
|
public SplittableRandom(long seed) { |
| 395 |
< |
this(seed, INITIAL_GAMMA); |
| 395 |
> |
this(seed, GOLDEN_GAMMA); |
| 396 |
|
} |
| 397 |
|
|
| 398 |
|
/** |
| 401 |
|
* of those of any other instances in the current program; and |
| 402 |
|
* may, and typically does, vary across program invocations. |
| 403 |
|
*/ |
| 404 |
< |
public SplittableRandom() { // emulate seeder.split() |
| 405 |
< |
this.gamma = nextGamma(this.seed = seeder.addAndGet(INITIAL_GAMMA)); |
| 404 |
> |
public SplittableRandom() { // emulate defaultGen.split() |
| 405 |
> |
long s = defaultGen.getAndAdd(2 * GOLDEN_GAMMA); |
| 406 |
> |
this.seed = mix64(s); |
| 407 |
> |
this.gamma = mixGamma(s + GOLDEN_GAMMA); |
| 408 |
|
} |
| 409 |
|
|
| 410 |
|
/** |
| 422 |
|
* @return the new SplittableRandom instance |
| 423 |
|
*/ |
| 424 |
|
public SplittableRandom split() { |
| 425 |
< |
long s = nextSeed(); |
| 393 |
< |
return new SplittableRandom(s, nextGamma(s)); |
| 425 |
> |
return new SplittableRandom(nextLong(), mixGamma(nextSeed())); |
| 426 |
|
} |
| 427 |
|
|
| 428 |
|
/** |
| 438 |
|
* Returns a pseudorandom {@code int} value between zero (inclusive) |
| 439 |
|
* and the specified bound (exclusive). |
| 440 |
|
* |
| 441 |
< |
* @param bound the bound on the random number to be returned. Must be |
| 410 |
< |
* positive. |
| 441 |
> |
* @param bound the upper bound (exclusive). Must be positive. |
| 442 |
|
* @return a pseudorandom {@code int} value between zero |
| 443 |
|
* (inclusive) and the bound (exclusive) |
| 444 |
|
* @throws IllegalArgumentException if {@code bound} is not positive |
| 490 |
|
* Returns a pseudorandom {@code long} value between zero (inclusive) |
| 491 |
|
* and the specified bound (exclusive). |
| 492 |
|
* |
| 493 |
< |
* @param bound the bound on the random number to be returned. Must be |
| 463 |
< |
* positive. |
| 493 |
> |
* @param bound the upper bound (exclusive). Must be positive. |
| 494 |
|
* @return a pseudorandom {@code long} value between zero |
| 495 |
|
* (inclusive) and the bound (exclusive) |
| 496 |
|
* @throws IllegalArgumentException if {@code bound} is not positive |
| 534 |
|
* (inclusive) and one (exclusive). |
| 535 |
|
* |
| 536 |
|
* @return a pseudorandom {@code double} value between zero |
| 537 |
< |
* (inclusive) and one (exclusive) |
| 537 |
> |
* (inclusive) and one (exclusive) |
| 538 |
|
*/ |
| 539 |
|
public double nextDouble() { |
| 540 |
|
return (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT; |
| 544 |
|
* Returns a pseudorandom {@code double} value between 0.0 |
| 545 |
|
* (inclusive) and the specified bound (exclusive). |
| 546 |
|
* |
| 547 |
< |
* @param bound the bound on the random number to be returned. Must be |
| 518 |
< |
* positive. |
| 547 |
> |
* @param bound the upper bound (exclusive). Must be positive. |
| 548 |
|
* @return a pseudorandom {@code double} value between zero |
| 549 |
|
* (inclusive) and the bound (exclusive) |
| 550 |
|
* @throws IllegalArgumentException if {@code bound} is not positive |
| 562 |
|
* origin (inclusive) and bound (exclusive). |
| 563 |
|
* |
| 564 |
|
* @param origin the least value returned |
| 565 |
< |
* @param bound the upper bound |
| 565 |
> |
* @param bound the upper bound (exclusive) |
| 566 |
|
* @return a pseudorandom {@code double} value between the origin |
| 567 |
|
* (inclusive) and the bound (exclusive) |
| 568 |
|
* @throws IllegalArgumentException if {@code origin} is greater than |
| 623 |
|
|
| 624 |
|
/** |
| 625 |
|
* Returns a stream producing the given {@code streamSize} number |
| 626 |
< |
* of pseudorandom {@code int} values, each conforming to the |
| 627 |
< |
* given origin and bound. |
| 626 |
> |
* of pseudorandom {@code int} values from this generator and/or one split |
| 627 |
> |
* from it; each value conforms to the given origin (inclusive) and bound |
| 628 |
> |
* (exclusive). |
| 629 |
|
* |
| 630 |
|
* @param streamSize the number of values to generate |
| 631 |
< |
* @param randomNumberOrigin the origin of each random value |
| 632 |
< |
* @param randomNumberBound the bound of each random value |
| 631 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
| 632 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
| 633 |
|
* @return a stream of pseudorandom {@code int} values, |
| 634 |
< |
* each with the given origin and bound |
| 634 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
| 635 |
|
* @throws IllegalArgumentException if {@code streamSize} is |
| 636 |
|
* less than zero, or {@code randomNumberOrigin} |
| 637 |
|
* is greater than or equal to {@code randomNumberBound} |
| 650 |
|
|
| 651 |
|
/** |
| 652 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
| 653 |
< |
* int} values, each conforming to the given origin and bound. |
| 653 |
> |
* int} values from this generator and/or one split from it; each value |
| 654 |
> |
* conforms to the given origin (inclusive) and bound (exclusive). |
| 655 |
|
* |
| 656 |
|
* @implNote This method is implemented to be equivalent to {@code |
| 657 |
|
* ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
| 658 |
|
* |
| 659 |
< |
* @param randomNumberOrigin the origin of each random value |
| 660 |
< |
* @param randomNumberBound the bound of each random value |
| 659 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
| 660 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
| 661 |
|
* @return a stream of pseudorandom {@code int} values, |
| 662 |
< |
* each with the given origin and bound |
| 662 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
| 663 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
| 664 |
|
* is greater than or equal to {@code randomNumberBound} |
| 665 |
|
*/ |
| 709 |
|
|
| 710 |
|
/** |
| 711 |
|
* Returns a stream producing the given {@code streamSize} number of |
| 712 |
< |
* pseudorandom {@code long} values, each conforming to the |
| 713 |
< |
* given origin and bound. |
| 712 |
> |
* pseudorandom {@code long} values from this generator and/or one split |
| 713 |
> |
* from it; each value conforms to the given origin (inclusive) and bound |
| 714 |
> |
* (exclusive). |
| 715 |
|
* |
| 716 |
|
* @param streamSize the number of values to generate |
| 717 |
< |
* @param randomNumberOrigin the origin of each random value |
| 718 |
< |
* @param randomNumberBound the bound of each random value |
| 717 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
| 718 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
| 719 |
|
* @return a stream of pseudorandom {@code long} values, |
| 720 |
< |
* each with the given origin and bound |
| 720 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
| 721 |
|
* @throws IllegalArgumentException if {@code streamSize} is |
| 722 |
|
* less than zero, or {@code randomNumberOrigin} |
| 723 |
|
* is greater than or equal to {@code randomNumberBound} |
| 736 |
|
|
| 737 |
|
/** |
| 738 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
| 739 |
< |
* long} values, each conforming to the given origin and bound. |
| 739 |
> |
* long} values from this generator and/or one split from it; each value |
| 740 |
> |
* conforms to the given origin (inclusive) and bound (exclusive). |
| 741 |
|
* |
| 742 |
|
* @implNote This method is implemented to be equivalent to {@code |
| 743 |
|
* longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
| 744 |
|
* |
| 745 |
< |
* @param randomNumberOrigin the origin of each random value |
| 746 |
< |
* @param randomNumberBound the bound of each random value |
| 745 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
| 746 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
| 747 |
|
* @return a stream of pseudorandom {@code long} values, |
| 748 |
< |
* each with the given origin and bound |
| 748 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
| 749 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
| 750 |
|
* is greater than or equal to {@code randomNumberBound} |
| 751 |
|
*/ |
| 760 |
|
|
| 761 |
|
/** |
| 762 |
|
* Returns a stream producing the given {@code streamSize} number of |
| 763 |
< |
* pseudorandom {@code double} values, each between zero |
| 764 |
< |
* (inclusive) and one (exclusive). |
| 763 |
> |
* pseudorandom {@code double} values from this generator and/or one split |
| 764 |
> |
* from it; each value is between zero (inclusive) and one (exclusive). |
| 765 |
|
* |
| 766 |
|
* @param streamSize the number of values to generate |
| 767 |
|
* @return a stream of {@code double} values |
| 779 |
|
|
| 780 |
|
/** |
| 781 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
| 782 |
< |
* double} values, each between zero (inclusive) and one |
| 783 |
< |
* (exclusive). |
| 782 |
> |
* double} values from this generator and/or one split from it; each value |
| 783 |
> |
* is between zero (inclusive) and one (exclusive). |
| 784 |
|
* |
| 785 |
|
* @implNote This method is implemented to be equivalent to {@code |
| 786 |
|
* doubles(Long.MAX_VALUE)}. |
| 796 |
|
|
| 797 |
|
/** |
| 798 |
|
* Returns a stream producing the given {@code streamSize} number of |
| 799 |
< |
* pseudorandom {@code double} values, each conforming to the |
| 800 |
< |
* given origin and bound. |
| 799 |
> |
* pseudorandom {@code double} values from this generator and/or one split |
| 800 |
> |
* from it; each value conforms to the given origin (inclusive) and bound |
| 801 |
> |
* (exclusive). |
| 802 |
|
* |
| 803 |
|
* @param streamSize the number of values to generate |
| 804 |
< |
* @param randomNumberOrigin the origin of each random value |
| 805 |
< |
* @param randomNumberBound the bound of each random value |
| 804 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
| 805 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
| 806 |
|
* @return a stream of pseudorandom {@code double} values, |
| 807 |
< |
* each with the given origin and bound |
| 807 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
| 808 |
|
* @throws IllegalArgumentException if {@code streamSize} is |
| 809 |
< |
* less than zero |
| 809 |
> |
* less than zero |
| 810 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
| 811 |
|
* is greater than or equal to {@code randomNumberBound} |
| 812 |
|
*/ |
| 824 |
|
|
| 825 |
|
/** |
| 826 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
| 827 |
< |
* double} values, each conforming to the given origin and bound. |
| 827 |
> |
* double} values from this generator and/or one split from it; each value |
| 828 |
> |
* conforms to the given origin (inclusive) and bound (exclusive). |
| 829 |
|
* |
| 830 |
|
* @implNote This method is implemented to be equivalent to {@code |
| 831 |
|
* doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
| 832 |
|
* |
| 833 |
< |
* @param randomNumberOrigin the origin of each random value |
| 834 |
< |
* @param randomNumberBound the bound of each random value |
| 833 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
| 834 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
| 835 |
|
* @return a stream of pseudorandom {@code double} values, |
| 836 |
< |
* each with the given origin and bound |
| 836 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
| 837 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
| 838 |
|
* is greater than or equal to {@code randomNumberBound} |
| 839 |
|
*/ |
