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package java.util; |
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import java.net.InetAddress; |
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import java.util.concurrent.atomic.AtomicLong; |
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< |
import java.util.Spliterator; |
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> |
import java.util.function.DoubleConsumer; |
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import java.util.function.IntConsumer; |
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import java.util.function.LongConsumer; |
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< |
import java.util.function.DoubleConsumer; |
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import java.util.stream.StreamSupport; |
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import java.util.stream.DoubleStream; |
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import java.util.stream.IntStream; |
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import java.util.stream.LongStream; |
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import java.util.stream.DoubleStream; |
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import java.util.stream.StreamSupport; |
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|
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/** |
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* A generator of uniform pseudorandom values applicable for use in |
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* (among other contexts) isolated parallel computations that may |
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* generate subtasks. Class SplittableRandom supports methods for |
40 |
> |
* generate subtasks. Class {@code SplittableRandom} supports methods for |
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* producing pseudorandom numbers of type {@code int}, {@code long}, |
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* and {@code double} with similar usages as for class |
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* {@link java.util.Random} but differs in the following ways: |
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* types and ranges, but similar properties are expected to hold, at |
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* least approximately, for others as well. The <em>period</em> |
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* (length of any series of generated values before it repeats) is at |
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* least 2<sup>64</sup>. </li> |
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* least 2<sup>64</sup>. |
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* |
57 |
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* <li> Method {@link #split} constructs and returns a new |
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* <li>Method {@link #split} constructs and returns a new |
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* SplittableRandom instance that shares no mutable state with the |
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* current instance. However, with very high probability, the |
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* values collectively generated by the two objects have the same |
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* statistical properties as if the same quantity of values were |
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* generated by a single thread using a single {@code |
63 |
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* SplittableRandom} object. </li> |
63 |
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* SplittableRandom} object. |
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* |
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* <li>Instances of SplittableRandom are <em>not</em> thread-safe. |
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* They are designed to be split, not shared, across threads. For |
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* |
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* <li>This class provides additional methods for generating random |
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* streams, that employ the above techniques when used in {@code |
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* stream.parallel()} mode.</li> |
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* stream.parallel()} mode. |
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* |
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* </ul> |
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* |
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* <p>Instances of {@code SplittableRandom} are not cryptographically |
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* secure. Consider instead using {@link java.security.SecureRandom} |
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* in security-sensitive applications. Additionally, |
81 |
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* default-constructed instances do not use a cryptographically random |
82 |
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* seed unless the {@linkplain System#getProperty system property} |
83 |
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* {@code java.util.secureRandomSeed} is set to {@code true}. |
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* |
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* @author Guy Steele |
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* @author Doug Lea |
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* @since 1.8 |
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*/ |
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public class SplittableRandom { |
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> |
public final class SplittableRandom { |
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|
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/* |
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* Implementation Overview. |
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* Methods nextLong, nextInt, and derivatives do not return the |
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* sequence (seed) values, but instead a hash-like bit-mix of |
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* their bits, producing more independently distributed sequences. |
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* For nextLong, the mix64 bit-mixing function computes the same |
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* value as the "64-bit finalizer" function in Austin Appleby's |
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* MurmurHash3 algorithm. See |
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* http://code.google.com/p/smhasher/wiki/MurmurHash3 , which |
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* comments: "The constants for the finalizers were generated by a |
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* simple simulated-annealing algorithm, and both avalanche all |
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* bits of 'h' to within 0.25% bias." The mix32 function is |
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* equivalent to (int)(mix64(seed) >>> 32), but faster because it |
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* omits a step that doesn't contribute to result. |
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* For nextLong, the mix64 function is based on David Stafford's |
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* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html) |
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* "Mix13" variant of the "64-bit finalizer" function in Austin |
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* Appleby's MurmurHash3 algorithm (see |
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* http://code.google.com/p/smhasher/wiki/MurmurHash3). The mix32 |
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* function is based on Stafford's Mix04 mix function, but returns |
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* the upper 32 bits cast as int. |
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* |
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* The split operation uses the current generator to form the seed |
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* and gamma for another SplittableRandom. To conservatively |
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* avoid potential correlations between seed and value generation, |
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* gamma selection (method nextGamma) uses the "Mix13" constants |
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* for MurmurHash3 described by David Stafford |
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* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html) |
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* To avoid potential weaknesses in bit-mixing transformations, we |
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* restrict gammas to odd values with at least 12 and no more than |
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* 52 bits set. Rather than rejecting candidates with too few or |
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* too many bits set, method nextGamma flips some bits (which has |
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* the effect of mapping at most 4 to any given gamma value). |
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* This reduces the effective set of 64bit odd gamma values by |
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* about 2<sup>14</sup>, a very tiny percentage, and serves as an |
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* gamma selection (method mixGamma) uses different |
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* (Murmurhash3's) mix constants. To avoid potential weaknesses |
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* in bit-mixing transformations, we restrict gammas to odd values |
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* with at least 24 0-1 or 1-0 bit transitions. Rather than |
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* rejecting candidates with too few or too many bits set, method |
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* mixGamma flips some bits (which has the effect of mapping at |
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* most 4 to any given gamma value). This reduces the effective |
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* set of 64bit odd gamma values by about 2%, and serves as an |
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* automated screening for sequence constant selection that is |
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* left as an empirical decision in some other hashing and crypto |
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* algorithms. |
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* avalanching. |
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* |
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* The default (no-argument) constructor, in essence, invokes |
138 |
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* split() for a common "seeder" SplittableRandom. Unlike other |
139 |
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* cases, this split must be performed in a thread-safe manner, so |
140 |
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* we use an AtomicLong to represent the seed rather than use an |
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* explicit SplittableRandom. To bootstrap the seeder, we start |
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* off using a seed based on current time and host. This serves as |
143 |
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* a slimmed-down (and insecure) variant of SecureRandom that also |
144 |
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* avoids stalls that may occur when using /dev/random. |
138 |
> |
* split() for a common "defaultGen" SplittableRandom. Unlike |
139 |
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* other cases, this split must be performed in a thread-safe |
140 |
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* manner, so we use an AtomicLong to represent the seed rather |
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* than use an explicit SplittableRandom. To bootstrap the |
142 |
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* defaultGen, we start off using a seed based on current time |
143 |
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* unless the java.util.secureRandomSeed property is set. This |
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* serves as a slimmed-down (and insecure) variant of SecureRandom |
145 |
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* that also avoids stalls that may occur when using /dev/random. |
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* |
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* It is a relatively simple matter to apply the basic design here |
148 |
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* to use 128 bit seeds. However, emulating 128bit arithmetic and |
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*/ |
156 |
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|
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/** |
158 |
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* The initial gamma value for (unsplit) SplittableRandoms. Must |
159 |
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* be odd with at least 12 and no more than 52 bits set. Currently |
158 |
< |
* set to the golden ratio scaled to 64bits. |
158 |
> |
* The golden ratio scaled to 64bits, used as the initial gamma |
159 |
> |
* value for (unsplit) SplittableRandoms. |
160 |
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*/ |
161 |
< |
private static final long INITIAL_GAMMA = 0x9e3779b97f4a7c15L; |
161 |
> |
private static final long GOLDEN_GAMMA = 0x9e3779b97f4a7c15L; |
162 |
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|
163 |
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/** |
164 |
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* The least non-zero value returned by nextDouble(). This value |
165 |
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* is scaled by a random value of 53 bits to produce a result. |
166 |
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*/ |
167 |
< |
private static final double DOUBLE_UNIT = 1.0 / (1L << 53); |
167 |
> |
private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53); |
168 |
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|
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/** |
170 |
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* The seed. Updated only via method nextSeed. |
185 |
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} |
186 |
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|
187 |
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/** |
188 |
< |
* Computes MurmurHash3 64bit mix function. |
188 |
> |
* Computes Stafford variant 13 of 64bit mix function. |
189 |
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*/ |
190 |
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private static long mix64(long z) { |
191 |
< |
z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; |
192 |
< |
z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L; |
193 |
< |
return z ^ (z >>> 33); |
191 |
> |
z = (z ^ (z >>> 30)) * 0xbf58476d1ce4e5b9L; |
192 |
> |
z = (z ^ (z >>> 27)) * 0x94d049bb133111ebL; |
193 |
> |
return z ^ (z >>> 31); |
194 |
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} |
195 |
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196 |
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/** |
197 |
< |
* Returns the 32 high bits of mix64(z) as int. |
197 |
> |
* Returns the 32 high bits of Stafford variant 4 mix64 function as int. |
198 |
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*/ |
199 |
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private static int mix32(long z) { |
200 |
< |
z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; |
201 |
< |
return (int)(((z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L) >>> 32); |
200 |
> |
z = (z ^ (z >>> 33)) * 0x62a9d9ed799705f5L; |
201 |
> |
return (int)(((z ^ (z >>> 28)) * 0xcb24d0a5c88c35b3L) >>> 32); |
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} |
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/** |
205 |
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* Returns the gamma value to use for a new split instance. |
206 |
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*/ |
207 |
< |
private static long nextGamma(long z) { |
208 |
< |
z = (z ^ (z >>> 30)) * 0xbf58476d1ce4e5b9L; // Stafford "Mix13" |
209 |
< |
z = (z ^ (z >>> 27)) * 0x94d049bb133111ebL; |
210 |
< |
z = (z ^ (z >>> 31)) | 1L; // force to be odd |
211 |
< |
int n = Long.bitCount(z); // ensure enough 0 and 1 bits |
212 |
< |
return (n < 12 || n > 52) ? z ^ 0xaaaaaaaaaaaaaaaaL : z; |
207 |
> |
private static long mixGamma(long z) { |
208 |
> |
z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; // MurmurHash3 mix constants |
209 |
> |
z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L; |
210 |
> |
z = (z ^ (z >>> 33)) | 1L; // force to be odd |
211 |
> |
int n = Long.bitCount(z ^ (z >>> 1)); // ensure enough transitions |
212 |
> |
return (n < 24) ? z ^ 0xaaaaaaaaaaaaaaaaL : z; |
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} |
214 |
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|
215 |
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/** |
219 |
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return seed += gamma; |
220 |
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} |
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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 |
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/** |
228 |
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* The seed generator for default constructors. |
229 |
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*/ |
230 |
< |
private static final AtomicLong seeder = |
231 |
< |
new AtomicLong(mix64((((long)hashedHostAddress()) << 32) ^ |
232 |
< |
System.currentTimeMillis()) ^ |
233 |
< |
mix64(System.nanoTime())); |
234 |
< |
|
235 |
< |
/** |
236 |
< |
* Returns hash of local host IP address, if available; else 0. |
237 |
< |
*/ |
238 |
< |
private static int hashedHostAddress() { |
239 |
< |
try { |
240 |
< |
return InetAddress.getLocalHost().hashCode(); |
241 |
< |
} catch (Exception ex) { |
242 |
< |
return 0; |
243 |
< |
} |
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; |
243 |
> |
for (int i = 1; i < 8; ++i) |
244 |
> |
s = (s << 8) | ((long)seedBytes[i] & 0xffL); |
245 |
> |
defaultGen.set(s); |
246 |
> |
} |
247 |
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} |
248 |
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|
240 |
– |
// IllegalArgumentException messages |
241 |
– |
static final String BadBound = "bound must be positive"; |
242 |
– |
static final String BadRange = "bound must be greater than origin"; |
243 |
– |
static final String BadSize = "size must be non-negative"; |
244 |
– |
|
249 |
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/* |
250 |
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* Internal versions of nextX methods used by streams, as well as |
251 |
|
* the public nextX(origin, bound) methods. These exist mainly to |
365 |
|
* @param seed the initial seed |
366 |
|
*/ |
367 |
|
public SplittableRandom(long seed) { |
368 |
< |
this(seed, INITIAL_GAMMA); |
368 |
> |
this(seed, GOLDEN_GAMMA); |
369 |
|
} |
370 |
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|
371 |
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/** |
374 |
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* of those of any other instances in the current program; and |
375 |
|
* may, and typically does, vary across program invocations. |
376 |
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*/ |
377 |
< |
public SplittableRandom() { // emulate seeder.split() |
378 |
< |
this.gamma = nextGamma(this.seed = seeder.addAndGet(INITIAL_GAMMA)); |
377 |
> |
public SplittableRandom() { // emulate defaultGen.split() |
378 |
> |
long s = defaultGen.getAndAdd(GOLDEN_GAMMA << 1); |
379 |
> |
this.seed = mix64(s); |
380 |
> |
this.gamma = mixGamma(s + GOLDEN_GAMMA); |
381 |
|
} |
382 |
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|
383 |
|
/** |
395 |
|
* @return the new SplittableRandom instance |
396 |
|
*/ |
397 |
|
public SplittableRandom split() { |
398 |
< |
long s = nextSeed(); |
399 |
< |
return new SplittableRandom(s, nextGamma(s)); |
398 |
> |
return new SplittableRandom(nextLong(), mixGamma(nextSeed())); |
399 |
> |
} |
400 |
> |
|
401 |
> |
/** |
402 |
> |
* Fills a user-supplied byte array with generated pseudorandom bytes. |
403 |
> |
* |
404 |
> |
* @param bytes the byte array to fill with pseudorandom bytes |
405 |
> |
* @throws NullPointerException if bytes is null |
406 |
> |
* @since 10 |
407 |
> |
*/ |
408 |
> |
public void nextBytes(byte[] bytes) { |
409 |
> |
int i = 0; |
410 |
> |
int len = bytes.length; |
411 |
> |
for (int words = len >> 3; words--> 0; ) { |
412 |
> |
long rnd = nextLong(); |
413 |
> |
for (int n = 8; n--> 0; rnd >>>= Byte.SIZE) |
414 |
> |
bytes[i++] = (byte)rnd; |
415 |
> |
} |
416 |
> |
if (i < len) |
417 |
> |
for (long rnd = nextLong(); i < len; rnd >>>= Byte.SIZE) |
418 |
> |
bytes[i++] = (byte)rnd; |
419 |
|
} |
420 |
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|
421 |
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/** |
431 |
|
* Returns a pseudorandom {@code int} value between zero (inclusive) |
432 |
|
* and the specified bound (exclusive). |
433 |
|
* |
434 |
< |
* @param bound the bound on the random number to be returned. Must be |
410 |
< |
* positive. |
434 |
> |
* @param bound the upper bound (exclusive). Must be positive. |
435 |
|
* @return a pseudorandom {@code int} value between zero |
436 |
|
* (inclusive) and the bound (exclusive) |
437 |
|
* @throws IllegalArgumentException if {@code bound} is not positive |
438 |
|
*/ |
439 |
|
public int nextInt(int bound) { |
440 |
|
if (bound <= 0) |
441 |
< |
throw new IllegalArgumentException(BadBound); |
441 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
442 |
|
// Specialize internalNextInt for origin 0 |
443 |
|
int r = mix32(nextSeed()); |
444 |
|
int m = bound - 1; |
466 |
|
*/ |
467 |
|
public int nextInt(int origin, int bound) { |
468 |
|
if (origin >= bound) |
469 |
< |
throw new IllegalArgumentException(BadRange); |
469 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
470 |
|
return internalNextInt(origin, bound); |
471 |
|
} |
472 |
|
|
483 |
|
* Returns a pseudorandom {@code long} value between zero (inclusive) |
484 |
|
* and the specified bound (exclusive). |
485 |
|
* |
486 |
< |
* @param bound the bound on the random number to be returned. Must be |
463 |
< |
* positive. |
486 |
> |
* @param bound the upper bound (exclusive). Must be positive. |
487 |
|
* @return a pseudorandom {@code long} value between zero |
488 |
|
* (inclusive) and the bound (exclusive) |
489 |
|
* @throws IllegalArgumentException if {@code bound} is not positive |
490 |
|
*/ |
491 |
|
public long nextLong(long bound) { |
492 |
|
if (bound <= 0) |
493 |
< |
throw new IllegalArgumentException(BadBound); |
493 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
494 |
|
// Specialize internalNextLong for origin 0 |
495 |
|
long r = mix64(nextSeed()); |
496 |
|
long m = bound - 1; |
518 |
|
*/ |
519 |
|
public long nextLong(long origin, long bound) { |
520 |
|
if (origin >= bound) |
521 |
< |
throw new IllegalArgumentException(BadRange); |
521 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
522 |
|
return internalNextLong(origin, bound); |
523 |
|
} |
524 |
|
|
527 |
|
* (inclusive) and one (exclusive). |
528 |
|
* |
529 |
|
* @return a pseudorandom {@code double} value between zero |
530 |
< |
* (inclusive) and one (exclusive) |
530 |
> |
* (inclusive) and one (exclusive) |
531 |
|
*/ |
532 |
|
public double nextDouble() { |
533 |
|
return (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT; |
537 |
|
* Returns a pseudorandom {@code double} value between 0.0 |
538 |
|
* (inclusive) and the specified bound (exclusive). |
539 |
|
* |
540 |
< |
* @param bound the bound on the random number to be returned. Must be |
518 |
< |
* positive. |
540 |
> |
* @param bound the upper bound (exclusive). Must be positive. |
541 |
|
* @return a pseudorandom {@code double} value between zero |
542 |
|
* (inclusive) and the bound (exclusive) |
543 |
|
* @throws IllegalArgumentException if {@code bound} is not positive |
544 |
|
*/ |
545 |
|
public double nextDouble(double bound) { |
546 |
|
if (!(bound > 0.0)) |
547 |
< |
throw new IllegalArgumentException(BadBound); |
547 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
548 |
|
double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound; |
549 |
|
return (result < bound) ? result : // correct for rounding |
550 |
|
Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1); |
555 |
|
* origin (inclusive) and bound (exclusive). |
556 |
|
* |
557 |
|
* @param origin the least value returned |
558 |
< |
* @param bound the upper bound |
558 |
> |
* @param bound the upper bound (exclusive) |
559 |
|
* @return a pseudorandom {@code double} value between the origin |
560 |
|
* (inclusive) and the bound (exclusive) |
561 |
|
* @throws IllegalArgumentException if {@code origin} is greater than |
563 |
|
*/ |
564 |
|
public double nextDouble(double origin, double bound) { |
565 |
|
if (!(origin < bound)) |
566 |
< |
throw new IllegalArgumentException(BadRange); |
566 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
567 |
|
return internalNextDouble(origin, bound); |
568 |
|
} |
569 |
|
|
591 |
|
*/ |
592 |
|
public IntStream ints(long streamSize) { |
593 |
|
if (streamSize < 0L) |
594 |
< |
throw new IllegalArgumentException(BadSize); |
594 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
595 |
|
return StreamSupport.intStream |
596 |
|
(new RandomIntsSpliterator |
597 |
|
(this, 0L, streamSize, Integer.MAX_VALUE, 0), |
616 |
|
|
617 |
|
/** |
618 |
|
* Returns a stream producing the given {@code streamSize} number |
619 |
< |
* of pseudorandom {@code int} values, each conforming to the |
620 |
< |
* given origin and bound. |
619 |
> |
* of pseudorandom {@code int} values from this generator and/or one split |
620 |
> |
* from it; each value conforms to the given origin (inclusive) and bound |
621 |
> |
* (exclusive). |
622 |
|
* |
623 |
|
* @param streamSize the number of values to generate |
624 |
< |
* @param randomNumberOrigin the origin of each random value |
625 |
< |
* @param randomNumberBound the bound of each random value |
624 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
625 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
626 |
|
* @return a stream of pseudorandom {@code int} values, |
627 |
< |
* each with the given origin and bound |
627 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
628 |
|
* @throws IllegalArgumentException if {@code streamSize} is |
629 |
|
* less than zero, or {@code randomNumberOrigin} |
630 |
|
* is greater than or equal to {@code randomNumberBound} |
632 |
|
public IntStream ints(long streamSize, int randomNumberOrigin, |
633 |
|
int randomNumberBound) { |
634 |
|
if (streamSize < 0L) |
635 |
< |
throw new IllegalArgumentException(BadSize); |
635 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
636 |
|
if (randomNumberOrigin >= randomNumberBound) |
637 |
< |
throw new IllegalArgumentException(BadRange); |
637 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
638 |
|
return StreamSupport.intStream |
639 |
|
(new RandomIntsSpliterator |
640 |
|
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound), |
643 |
|
|
644 |
|
/** |
645 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
646 |
< |
* int} values, each conforming to the given origin and bound. |
646 |
> |
* int} values from this generator and/or one split from it; each value |
647 |
> |
* conforms to the given origin (inclusive) and bound (exclusive). |
648 |
|
* |
649 |
|
* @implNote This method is implemented to be equivalent to {@code |
650 |
|
* ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
651 |
|
* |
652 |
< |
* @param randomNumberOrigin the origin of each random value |
653 |
< |
* @param randomNumberBound the bound of each random value |
652 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
653 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
654 |
|
* @return a stream of pseudorandom {@code int} values, |
655 |
< |
* each with the given origin and bound |
655 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
656 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
657 |
|
* is greater than or equal to {@code randomNumberBound} |
658 |
|
*/ |
659 |
|
public IntStream ints(int randomNumberOrigin, int randomNumberBound) { |
660 |
|
if (randomNumberOrigin >= randomNumberBound) |
661 |
< |
throw new IllegalArgumentException(BadRange); |
661 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
662 |
|
return StreamSupport.intStream |
663 |
|
(new RandomIntsSpliterator |
664 |
|
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
677 |
|
*/ |
678 |
|
public LongStream longs(long streamSize) { |
679 |
|
if (streamSize < 0L) |
680 |
< |
throw new IllegalArgumentException(BadSize); |
680 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
681 |
|
return StreamSupport.longStream |
682 |
|
(new RandomLongsSpliterator |
683 |
|
(this, 0L, streamSize, Long.MAX_VALUE, 0L), |
702 |
|
|
703 |
|
/** |
704 |
|
* Returns a stream producing the given {@code streamSize} number of |
705 |
< |
* pseudorandom {@code long} values, each conforming to the |
706 |
< |
* given origin and bound. |
705 |
> |
* pseudorandom {@code long} values from this generator and/or one split |
706 |
> |
* from it; each value conforms to the given origin (inclusive) and bound |
707 |
> |
* (exclusive). |
708 |
|
* |
709 |
|
* @param streamSize the number of values to generate |
710 |
< |
* @param randomNumberOrigin the origin of each random value |
711 |
< |
* @param randomNumberBound the bound of each random value |
710 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
711 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
712 |
|
* @return a stream of pseudorandom {@code long} values, |
713 |
< |
* each with the given origin and bound |
713 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
714 |
|
* @throws IllegalArgumentException if {@code streamSize} is |
715 |
|
* less than zero, or {@code randomNumberOrigin} |
716 |
|
* is greater than or equal to {@code randomNumberBound} |
718 |
|
public LongStream longs(long streamSize, long randomNumberOrigin, |
719 |
|
long randomNumberBound) { |
720 |
|
if (streamSize < 0L) |
721 |
< |
throw new IllegalArgumentException(BadSize); |
721 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
722 |
|
if (randomNumberOrigin >= randomNumberBound) |
723 |
< |
throw new IllegalArgumentException(BadRange); |
723 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
724 |
|
return StreamSupport.longStream |
725 |
|
(new RandomLongsSpliterator |
726 |
|
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound), |
729 |
|
|
730 |
|
/** |
731 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
732 |
< |
* long} values, each conforming to the given origin and bound. |
732 |
> |
* long} values from this generator and/or one split from it; each value |
733 |
> |
* conforms to the given origin (inclusive) and bound (exclusive). |
734 |
|
* |
735 |
|
* @implNote This method is implemented to be equivalent to {@code |
736 |
|
* longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
737 |
|
* |
738 |
< |
* @param randomNumberOrigin the origin of each random value |
739 |
< |
* @param randomNumberBound the bound of each random value |
738 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
739 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
740 |
|
* @return a stream of pseudorandom {@code long} values, |
741 |
< |
* each with the given origin and bound |
741 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
742 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
743 |
|
* is greater than or equal to {@code randomNumberBound} |
744 |
|
*/ |
745 |
|
public LongStream longs(long randomNumberOrigin, long randomNumberBound) { |
746 |
|
if (randomNumberOrigin >= randomNumberBound) |
747 |
< |
throw new IllegalArgumentException(BadRange); |
747 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
748 |
|
return StreamSupport.longStream |
749 |
|
(new RandomLongsSpliterator |
750 |
|
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
753 |
|
|
754 |
|
/** |
755 |
|
* Returns a stream producing the given {@code streamSize} number of |
756 |
< |
* pseudorandom {@code double} values, each between zero |
757 |
< |
* (inclusive) and one (exclusive). |
756 |
> |
* pseudorandom {@code double} values from this generator and/or one split |
757 |
> |
* from it; each value is between zero (inclusive) and one (exclusive). |
758 |
|
* |
759 |
|
* @param streamSize the number of values to generate |
760 |
|
* @return a stream of {@code double} values |
763 |
|
*/ |
764 |
|
public DoubleStream doubles(long streamSize) { |
765 |
|
if (streamSize < 0L) |
766 |
< |
throw new IllegalArgumentException(BadSize); |
766 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
767 |
|
return StreamSupport.doubleStream |
768 |
|
(new RandomDoublesSpliterator |
769 |
|
(this, 0L, streamSize, Double.MAX_VALUE, 0.0), |
772 |
|
|
773 |
|
/** |
774 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
775 |
< |
* double} values, each between zero (inclusive) and one |
776 |
< |
* (exclusive). |
775 |
> |
* double} values from this generator and/or one split from it; each value |
776 |
> |
* is between zero (inclusive) and one (exclusive). |
777 |
|
* |
778 |
|
* @implNote This method is implemented to be equivalent to {@code |
779 |
|
* doubles(Long.MAX_VALUE)}. |
789 |
|
|
790 |
|
/** |
791 |
|
* Returns a stream producing the given {@code streamSize} number of |
792 |
< |
* pseudorandom {@code double} values, each conforming to the |
793 |
< |
* given origin and bound. |
792 |
> |
* pseudorandom {@code double} values from this generator and/or one split |
793 |
> |
* from it; each value conforms to the given origin (inclusive) and bound |
794 |
> |
* (exclusive). |
795 |
|
* |
796 |
|
* @param streamSize the number of values to generate |
797 |
< |
* @param randomNumberOrigin the origin of each random value |
798 |
< |
* @param randomNumberBound the bound of each random value |
797 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
798 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
799 |
|
* @return a stream of pseudorandom {@code double} values, |
800 |
< |
* each with the given origin and bound |
800 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
801 |
|
* @throws IllegalArgumentException if {@code streamSize} is |
802 |
< |
* less than zero |
776 |
< |
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
802 |
> |
* less than zero, or {@code randomNumberOrigin} |
803 |
|
* is greater than or equal to {@code randomNumberBound} |
804 |
|
*/ |
805 |
|
public DoubleStream doubles(long streamSize, double randomNumberOrigin, |
806 |
|
double randomNumberBound) { |
807 |
|
if (streamSize < 0L) |
808 |
< |
throw new IllegalArgumentException(BadSize); |
808 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
809 |
|
if (!(randomNumberOrigin < randomNumberBound)) |
810 |
< |
throw new IllegalArgumentException(BadRange); |
810 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
811 |
|
return StreamSupport.doubleStream |
812 |
|
(new RandomDoublesSpliterator |
813 |
|
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound), |
816 |
|
|
817 |
|
/** |
818 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
819 |
< |
* double} values, each conforming to the given origin and bound. |
819 |
> |
* double} values from this generator and/or one split from it; each value |
820 |
> |
* conforms to the given origin (inclusive) and bound (exclusive). |
821 |
|
* |
822 |
|
* @implNote This method is implemented to be equivalent to {@code |
823 |
|
* doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
824 |
|
* |
825 |
< |
* @param randomNumberOrigin the origin of each random value |
826 |
< |
* @param randomNumberBound the bound of each random value |
825 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
826 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
827 |
|
* @return a stream of pseudorandom {@code double} values, |
828 |
< |
* each with the given origin and bound |
828 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
829 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
830 |
|
* is greater than or equal to {@code randomNumberBound} |
831 |
|
*/ |
832 |
|
public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) { |
833 |
|
if (!(randomNumberOrigin < randomNumberBound)) |
834 |
< |
throw new IllegalArgumentException(BadRange); |
834 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
835 |
|
return StreamSupport.doubleStream |
836 |
|
(new RandomDoublesSpliterator |
837 |
|
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
846 |
|
* approach. The long and double versions of this class are |
847 |
|
* identical except for types. |
848 |
|
*/ |
849 |
< |
static final class RandomIntsSpliterator implements Spliterator.OfInt { |
849 |
> |
private static final class RandomIntsSpliterator |
850 |
> |
implements Spliterator.OfInt { |
851 |
|
final SplittableRandom rng; |
852 |
|
long index; |
853 |
|
final long fence; |
902 |
|
/** |
903 |
|
* Spliterator for long streams. |
904 |
|
*/ |
905 |
< |
static final class RandomLongsSpliterator implements Spliterator.OfLong { |
905 |
> |
private static final class RandomLongsSpliterator |
906 |
> |
implements Spliterator.OfLong { |
907 |
|
final SplittableRandom rng; |
908 |
|
long index; |
909 |
|
final long fence; |
959 |
|
/** |
960 |
|
* Spliterator for double streams. |
961 |
|
*/ |
962 |
< |
static final class RandomDoublesSpliterator implements Spliterator.OfDouble { |
962 |
> |
private static final class RandomDoublesSpliterator |
963 |
> |
implements Spliterator.OfDouble { |
964 |
|
final SplittableRandom rng; |
965 |
|
long index; |
966 |
|
final long fence; |