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dl |
1.1 |
/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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jsr166 |
1.8 |
* http://creativecommons.org/publicdomain/zero/1.0/ |
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dl |
1.1 |
*/ |
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import junit.framework.*; |
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import java.util.*; |
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jsr166 |
1.10 |
import java.util.concurrent.ThreadLocalRandom; |
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jsr166 |
1.11 |
import java.util.concurrent.atomic.AtomicLong; |
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import java.util.concurrent.atomic.AtomicReference; |
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dl |
1.1 |
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public class ThreadLocalRandomTest extends JSR166TestCase { |
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public static void main(String[] args) { |
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jsr166 |
1.7 |
junit.textui.TestRunner.run(suite()); |
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dl |
1.1 |
} |
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public static Test suite() { |
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jsr166 |
1.4 |
return new TestSuite(ThreadLocalRandomTest.class); |
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dl |
1.1 |
} |
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jsr166 |
1.13 |
/* |
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dl |
1.1 |
* Testing coverage notes: |
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jsr166 |
1.2 |
* |
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dl |
1.1 |
* We don't test randomness properties, but only that repeated |
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* calls, up to NCALLS tries, produce at least one different |
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* result. For bounded versions, we sample various intervals |
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* across multiples of primes. |
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*/ |
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jsr166 |
1.14 |
// max numbers of calls to detect getting stuck on one value |
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dl |
1.1 |
static final int NCALLS = 10000; |
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// max sampled int bound |
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static final int MAX_INT_BOUND = (1 << 28); |
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jsr166 |
1.14 |
// max sampled long bound |
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dl |
1.1 |
static final long MAX_LONG_BOUND = (1L << 42); |
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dl |
1.15 |
// Number of replications for other checks |
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static final int REPS = 20; |
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dl |
1.1 |
/** |
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* setSeed throws UnsupportedOperationException |
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*/ |
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public void testSetSeed() { |
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try { |
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ThreadLocalRandom.current().setSeed(17); |
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jsr166 |
1.3 |
shouldThrow(); |
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jsr166 |
1.5 |
} catch (UnsupportedOperationException success) {} |
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dl |
1.1 |
} |
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/** |
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jsr166 |
1.14 |
* Repeated calls to nextInt produce at least two distinct results |
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dl |
1.1 |
*/ |
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public void testNextInt() { |
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int f = ThreadLocalRandom.current().nextInt(); |
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int i = 0; |
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while (i < NCALLS && ThreadLocalRandom.current().nextInt() == f) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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/** |
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jsr166 |
1.14 |
* Repeated calls to nextLong produce at least two distinct results |
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dl |
1.1 |
*/ |
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public void testNextLong() { |
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long f = ThreadLocalRandom.current().nextLong(); |
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int i = 0; |
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while (i < NCALLS && ThreadLocalRandom.current().nextLong() == f) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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/** |
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jsr166 |
1.14 |
* Repeated calls to nextBoolean produce at least two distinct results |
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dl |
1.1 |
*/ |
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public void testNextBoolean() { |
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boolean f = ThreadLocalRandom.current().nextBoolean(); |
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int i = 0; |
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while (i < NCALLS && ThreadLocalRandom.current().nextBoolean() == f) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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/** |
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jsr166 |
1.14 |
* Repeated calls to nextFloat produce at least two distinct results |
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dl |
1.1 |
*/ |
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public void testNextFloat() { |
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float f = ThreadLocalRandom.current().nextFloat(); |
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int i = 0; |
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while (i < NCALLS && ThreadLocalRandom.current().nextFloat() == f) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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/** |
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jsr166 |
1.14 |
* Repeated calls to nextDouble produce at least two distinct results |
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dl |
1.1 |
*/ |
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public void testNextDouble() { |
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double f = ThreadLocalRandom.current().nextDouble(); |
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jsr166 |
1.14 |
int i = 0; |
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dl |
1.1 |
while (i < NCALLS && ThreadLocalRandom.current().nextDouble() == f) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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/** |
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jsr166 |
1.14 |
* Repeated calls to nextGaussian produce at least two distinct results |
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dl |
1.1 |
*/ |
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public void testNextGaussian() { |
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double f = ThreadLocalRandom.current().nextGaussian(); |
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int i = 0; |
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while (i < NCALLS && ThreadLocalRandom.current().nextGaussian() == f) |
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++i; |
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assertTrue(i < NCALLS); |
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} |
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/** |
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jsr166 |
1.14 |
* nextInt(negative) throws IllegalArgumentException |
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dl |
1.1 |
*/ |
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public void testNextIntBoundedNeg() { |
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try { |
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jsr166 |
1.6 |
int f = ThreadLocalRandom.current().nextInt(-17); |
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jsr166 |
1.3 |
shouldThrow(); |
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jsr166 |
1.5 |
} catch (IllegalArgumentException success) {} |
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dl |
1.1 |
} |
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/** |
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jsr166 |
1.14 |
* nextInt(least >= bound) throws IllegalArgumentException |
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dl |
1.1 |
*/ |
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public void testNextIntBadBounds() { |
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try { |
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jsr166 |
1.6 |
int f = ThreadLocalRandom.current().nextInt(17, 2); |
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jsr166 |
1.3 |
shouldThrow(); |
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jsr166 |
1.5 |
} catch (IllegalArgumentException success) {} |
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dl |
1.1 |
} |
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/** |
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* nextInt(bound) returns 0 <= value < bound; |
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jsr166 |
1.14 |
* repeated calls produce at least two distinct results |
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dl |
1.1 |
*/ |
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public void testNextIntBounded() { |
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// sample bound space across prime number increments |
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for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) { |
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int f = ThreadLocalRandom.current().nextInt(bound); |
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assertTrue(0 <= f && f < bound); |
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int i = 0; |
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int j; |
149 |
jsr166 |
1.2 |
while (i < NCALLS && |
150 |
dl |
1.1 |
(j = ThreadLocalRandom.current().nextInt(bound)) == f) { |
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assertTrue(0 <= j && j < bound); |
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++i; |
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} |
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assertTrue(i < NCALLS); |
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} |
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} |
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/** |
159 |
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* nextInt(least, bound) returns least <= value < bound; |
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jsr166 |
1.14 |
* repeated calls produce at least two distinct results |
161 |
dl |
1.1 |
*/ |
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public void testNextIntBounded2() { |
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for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) { |
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for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) { |
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int f = ThreadLocalRandom.current().nextInt(least, bound); |
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assertTrue(least <= f && f < bound); |
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int i = 0; |
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int j; |
169 |
jsr166 |
1.2 |
while (i < NCALLS && |
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dl |
1.1 |
(j = ThreadLocalRandom.current().nextInt(least, bound)) == f) { |
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assertTrue(least <= j && j < bound); |
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++i; |
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} |
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assertTrue(i < NCALLS); |
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} |
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} |
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} |
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/** |
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jsr166 |
1.14 |
* nextLong(negative) throws IllegalArgumentException |
181 |
dl |
1.1 |
*/ |
182 |
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public void testNextLongBoundedNeg() { |
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try { |
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jsr166 |
1.6 |
long f = ThreadLocalRandom.current().nextLong(-17); |
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jsr166 |
1.3 |
shouldThrow(); |
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jsr166 |
1.5 |
} catch (IllegalArgumentException success) {} |
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dl |
1.1 |
} |
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/** |
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jsr166 |
1.14 |
* nextLong(least >= bound) throws IllegalArgumentException |
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dl |
1.1 |
*/ |
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public void testNextLongBadBounds() { |
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try { |
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jsr166 |
1.6 |
long f = ThreadLocalRandom.current().nextLong(17, 2); |
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jsr166 |
1.3 |
shouldThrow(); |
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jsr166 |
1.5 |
} catch (IllegalArgumentException success) {} |
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dl |
1.1 |
} |
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/** |
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* nextLong(bound) returns 0 <= value < bound; |
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jsr166 |
1.14 |
* repeated calls produce at least two distinct results |
202 |
dl |
1.1 |
*/ |
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public void testNextLongBounded() { |
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for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) { |
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long f = ThreadLocalRandom.current().nextLong(bound); |
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assertTrue(0 <= f && f < bound); |
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int i = 0; |
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long j; |
209 |
jsr166 |
1.2 |
while (i < NCALLS && |
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dl |
1.1 |
(j = ThreadLocalRandom.current().nextLong(bound)) == f) { |
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assertTrue(0 <= j && j < bound); |
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++i; |
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} |
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assertTrue(i < NCALLS); |
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} |
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} |
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/** |
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* nextLong(least, bound) returns least <= value < bound; |
220 |
jsr166 |
1.14 |
* repeated calls produce at least two distinct results |
221 |
dl |
1.1 |
*/ |
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public void testNextLongBounded2() { |
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for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) { |
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for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) { |
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long f = ThreadLocalRandom.current().nextLong(least, bound); |
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assertTrue(least <= f && f < bound); |
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int i = 0; |
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long j; |
229 |
jsr166 |
1.2 |
while (i < NCALLS && |
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dl |
1.1 |
(j = ThreadLocalRandom.current().nextLong(least, bound)) == f) { |
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assertTrue(least <= j && j < bound); |
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++i; |
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} |
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assertTrue(i < NCALLS); |
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} |
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} |
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} |
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/** |
240 |
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* nextDouble(least, bound) returns least <= value < bound; |
241 |
jsr166 |
1.14 |
* repeated calls produce at least two distinct results |
242 |
dl |
1.1 |
*/ |
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public void testNextDoubleBounded2() { |
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for (double least = 0.0001; least < 1.0e20; least *= 8) { |
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for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) { |
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double f = ThreadLocalRandom.current().nextDouble(least, bound); |
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assertTrue(least <= f && f < bound); |
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int i = 0; |
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double j; |
250 |
jsr166 |
1.2 |
while (i < NCALLS && |
251 |
dl |
1.1 |
(j = ThreadLocalRandom.current().nextDouble(least, bound)) == f) { |
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assertTrue(least <= j && j < bound); |
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++i; |
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} |
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assertTrue(i < NCALLS); |
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} |
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} |
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} |
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260 |
jsr166 |
1.11 |
/** |
261 |
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* Different threads produce different pseudo-random sequences |
262 |
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*/ |
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public void testDifferentSequences() { |
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// Don't use main thread's ThreadLocalRandom - it is likely to |
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// be polluted by previous tests. |
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final AtomicReference<ThreadLocalRandom> threadLocalRandom = |
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new AtomicReference<ThreadLocalRandom>(); |
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final AtomicLong rand = new AtomicLong(); |
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long firstRand = 0; |
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ThreadLocalRandom firstThreadLocalRandom = null; |
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273 |
jsr166 |
1.18 |
Runnable getRandomState = new CheckedRunnable() { |
274 |
jsr166 |
1.11 |
public void realRun() { |
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ThreadLocalRandom current = ThreadLocalRandom.current(); |
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assertSame(current, ThreadLocalRandom.current()); |
277 |
dl |
1.12 |
// test bug: the following is not guaranteed and not true in JDK8 |
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// assertNotSame(current, threadLocalRandom.get()); |
279 |
jsr166 |
1.11 |
rand.set(current.nextLong()); |
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threadLocalRandom.set(current); |
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}}; |
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Thread first = newStartedThread(getRandomState); |
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awaitTermination(first); |
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firstRand = rand.get(); |
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firstThreadLocalRandom = threadLocalRandom.get(); |
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288 |
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for (int i = 0; i < NCALLS; i++) { |
289 |
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Thread t = newStartedThread(getRandomState); |
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awaitTermination(t); |
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if (firstRand != rand.get()) |
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return; |
293 |
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} |
294 |
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fail("all threads generate the same pseudo-random sequence"); |
295 |
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} |
296 |
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297 |
dl |
1.1 |
} |