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/* |
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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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* http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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import junit.framework.*; |
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import java.util.*; |
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import java.util.concurrent.ThreadLocalRandom; |
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import java.util.concurrent.atomic.AtomicLong; |
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import java.util.concurrent.atomic.AtomicInteger; |
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import java.util.concurrent.atomic.AtomicReference; |
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import java.util.concurrent.atomic.LongAdder; |
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|
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public class ThreadLocalRandomTest extends JSR166TestCase { |
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|
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public static void main(String[] args) { |
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junit.textui.TestRunner.run(suite()); |
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} |
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public static Test suite() { |
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return new TestSuite(ThreadLocalRandomTest.class); |
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} |
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|
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/* |
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* Testing coverage notes: |
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* |
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* 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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|
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// max numbers of calls to detect getting stuck on one value |
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static final int NCALLS = 10000; |
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|
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// max sampled int bound |
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static final int MAX_INT_BOUND = (1 << 28); |
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|
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// max sampled long bound |
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static final long MAX_LONG_BOUND = (1L << 42); |
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|
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// Number of replications for other checks |
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static final int REPS = 20; |
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|
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/** |
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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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shouldThrow(); |
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} catch (UnsupportedOperationException success) {} |
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} |
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|
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/** |
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* Repeated calls to nextInt produce at least two distinct results |
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*/ |
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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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/** |
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* Repeated calls to nextLong produce at least two distinct results |
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*/ |
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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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/** |
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* Repeated calls to nextBoolean produce at least two distinct results |
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*/ |
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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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/** |
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* Repeated calls to nextFloat produce at least two distinct results |
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*/ |
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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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/** |
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* Repeated calls to nextDouble produce at least two distinct results |
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*/ |
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public void testNextDouble() { |
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double f = ThreadLocalRandom.current().nextDouble(); |
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int i = 0; |
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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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/** |
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* Repeated calls to nextGaussian produce at least two distinct results |
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*/ |
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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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/** |
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* nextInt(negative) throws IllegalArgumentException |
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*/ |
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public void testNextIntBoundedNeg() { |
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try { |
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int f = ThreadLocalRandom.current().nextInt(-17); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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} |
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|
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/** |
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* nextInt(least >= bound) throws IllegalArgumentException |
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*/ |
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public void testNextIntBadBounds() { |
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try { |
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int f = ThreadLocalRandom.current().nextInt(17, 2); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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} |
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|
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/** |
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* nextInt(bound) returns 0 <= value < bound; |
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* repeated calls produce at least two distinct results |
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*/ |
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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; |
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while (i < NCALLS && |
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(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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|
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/** |
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* nextInt(least, bound) returns least <= value < bound; |
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* repeated calls produce at least two distinct results |
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*/ |
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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; |
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while (i < NCALLS && |
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(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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/** |
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* nextLong(negative) throws IllegalArgumentException |
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*/ |
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public void testNextLongBoundedNeg() { |
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try { |
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long f = ThreadLocalRandom.current().nextLong(-17); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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} |
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|
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/** |
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* nextLong(least >= bound) throws IllegalArgumentException |
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*/ |
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public void testNextLongBadBounds() { |
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try { |
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long f = ThreadLocalRandom.current().nextLong(17, 2); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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} |
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|
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/** |
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* nextLong(bound) returns 0 <= value < bound; |
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* repeated calls produce at least two distinct results |
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*/ |
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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; |
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while (i < NCALLS && |
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(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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/** |
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* nextLong(least, bound) returns least <= value < bound; |
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* repeated calls produce at least two distinct results |
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*/ |
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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; |
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while (i < NCALLS && |
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(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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|
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/** |
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* nextDouble(least, bound) returns least <= value < bound; |
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* repeated calls produce at least two distinct results |
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*/ |
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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; |
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while (i < NCALLS && |
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(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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|
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/** |
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* Different threads produce different pseudo-random sequences |
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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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|
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long firstRand = 0; |
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ThreadLocalRandom firstThreadLocalRandom = null; |
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|
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final CheckedRunnable getRandomState = new CheckedRunnable() { |
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public void realRun() { |
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ThreadLocalRandom current = ThreadLocalRandom.current(); |
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assertSame(current, ThreadLocalRandom.current()); |
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// test bug: the following is not guaranteed and not true in JDK8 |
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// assertNotSame(current, threadLocalRandom.get()); |
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rand.set(current.nextLong()); |
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threadLocalRandom.set(current); |
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}}; |
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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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|
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for (int i = 0; i < NCALLS; i++) { |
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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; |
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} |
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fail("all threads generate the same pseudo-random sequence"); |
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} |
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|
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/** |
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* Invoking sized ints, long, doubles, with negative sizes throws |
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* IllegalArgumentException |
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*/ |
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public void testBadStreamSize() { |
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ThreadLocalRandom r = ThreadLocalRandom.current(); |
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try { |
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java.util.stream.IntStream x = r.ints(-1L); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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try { |
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java.util.stream.IntStream x = r.ints(-1L, 2, 3); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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try { |
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java.util.stream.LongStream x = r.longs(-1L); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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try { |
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java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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try { |
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java.util.stream.DoubleStream x = r.doubles(-1L); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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try { |
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java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
329 |
} |
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|
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/** |
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* Invoking bounded ints, long, doubles, with illegal bounds throws |
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* IllegalArgumentException |
334 |
*/ |
335 |
public void testBadStreamBounds() { |
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ThreadLocalRandom r = ThreadLocalRandom.current(); |
337 |
try { |
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java.util.stream.IntStream x = r.ints(2, 1); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
341 |
try { |
342 |
java.util.stream.IntStream x = r.ints(10, 42, 42); |
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shouldThrow(); |
344 |
} catch (IllegalArgumentException success) {} |
345 |
try { |
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java.util.stream.LongStream x = r.longs(-1L, -1L); |
347 |
shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
349 |
try { |
350 |
java.util.stream.LongStream x = r.longs(10, 1L, -2L); |
351 |
shouldThrow(); |
352 |
} catch (IllegalArgumentException success) {} |
353 |
try { |
354 |
java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); |
355 |
shouldThrow(); |
356 |
} catch (IllegalArgumentException success) {} |
357 |
try { |
358 |
java.util.stream.DoubleStream x = r.doubles(10, .5, .4); |
359 |
shouldThrow(); |
360 |
} catch (IllegalArgumentException success) {} |
361 |
} |
362 |
|
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/** |
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* A parallel sized stream of ints generates the given number of values |
365 |
*/ |
366 |
public void testIntsCount() { |
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LongAdder counter = new LongAdder(); |
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ThreadLocalRandom r = ThreadLocalRandom.current(); |
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long size = 0; |
370 |
for (int reps = 0; reps < REPS; ++reps) { |
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counter.reset(); |
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r.ints(size).parallel().forEach(x -> {counter.increment();}); |
373 |
assertEquals(size, counter.sum()); |
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size += 524959; |
375 |
} |
376 |
} |
377 |
|
378 |
/** |
379 |
* A parallel sized stream of longs generates the given number of values |
380 |
*/ |
381 |
public void testLongsCount() { |
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LongAdder counter = new LongAdder(); |
383 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
384 |
long size = 0; |
385 |
for (int reps = 0; reps < REPS; ++reps) { |
386 |
counter.reset(); |
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r.longs(size).parallel().forEach(x -> {counter.increment();}); |
388 |
assertEquals(size, counter.sum()); |
389 |
size += 524959; |
390 |
} |
391 |
} |
392 |
|
393 |
/** |
394 |
* A parallel sized stream of doubles generates the given number of values |
395 |
*/ |
396 |
public void testDoublesCount() { |
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LongAdder counter = new LongAdder(); |
398 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
399 |
long size = 0; |
400 |
for (int reps = 0; reps < REPS; ++reps) { |
401 |
counter.reset(); |
402 |
r.doubles(size).parallel().forEach(x -> {counter.increment();}); |
403 |
assertEquals(size, counter.sum()); |
404 |
size += 524959; |
405 |
} |
406 |
} |
407 |
|
408 |
/** |
409 |
* Each of a parallel sized stream of bounded ints is within bounds |
410 |
*/ |
411 |
public void testBoundedInts() { |
412 |
AtomicInteger fails = new AtomicInteger(0); |
413 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
414 |
long size = 12345L; |
415 |
for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) { |
416 |
for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) { |
417 |
final int lo = least, hi = bound; |
418 |
r.ints(size, lo, hi).parallel(). |
419 |
forEach(x -> {if (x < lo || x >= hi) |
420 |
fails.getAndIncrement(); }); |
421 |
} |
422 |
} |
423 |
assertEquals(0, fails.get()); |
424 |
} |
425 |
|
426 |
/** |
427 |
* Each of a parallel sized stream of bounded longs is within bounds |
428 |
*/ |
429 |
public void testBoundedLongs() { |
430 |
AtomicInteger fails = new AtomicInteger(0); |
431 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
432 |
long size = 123L; |
433 |
for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) { |
434 |
for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) { |
435 |
final long lo = least, hi = bound; |
436 |
r.longs(size, lo, hi).parallel(). |
437 |
forEach(x -> {if (x < lo || x >= hi) |
438 |
fails.getAndIncrement(); }); |
439 |
} |
440 |
} |
441 |
assertEquals(0, fails.get()); |
442 |
} |
443 |
|
444 |
/** |
445 |
* Each of a parallel sized stream of bounded doubles is within bounds |
446 |
*/ |
447 |
public void testBoundedDoubles() { |
448 |
AtomicInteger fails = new AtomicInteger(0); |
449 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
450 |
long size = 456; |
451 |
for (double least = 0.00011; least < 1.0e20; least *= 9) { |
452 |
for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) { |
453 |
final double lo = least, hi = bound; |
454 |
r.doubles(size, lo, hi).parallel(). |
455 |
forEach(x -> {if (x < lo || x >= hi) |
456 |
fails.getAndIncrement(); }); |
457 |
} |
458 |
} |
459 |
assertEquals(0, fails.get()); |
460 |
} |
461 |
|
462 |
/** |
463 |
* A parallel unsized stream of ints generates at least 100 values |
464 |
*/ |
465 |
public void testUnsizedIntsCount() { |
466 |
LongAdder counter = new LongAdder(); |
467 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
468 |
long size = 100; |
469 |
r.ints().limit(size).parallel().forEach(x -> {counter.increment();}); |
470 |
assertEquals(size, counter.sum()); |
471 |
} |
472 |
|
473 |
/** |
474 |
* A parallel unsized stream of longs generates at least 100 values |
475 |
*/ |
476 |
public void testUnsizedLongsCount() { |
477 |
LongAdder counter = new LongAdder(); |
478 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
479 |
long size = 100; |
480 |
r.longs().limit(size).parallel().forEach(x -> {counter.increment();}); |
481 |
assertEquals(size, counter.sum()); |
482 |
} |
483 |
|
484 |
/** |
485 |
* A parallel unsized stream of doubles generates at least 100 values |
486 |
*/ |
487 |
public void testUnsizedDoublesCount() { |
488 |
LongAdder counter = new LongAdder(); |
489 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
490 |
long size = 100; |
491 |
r.doubles().limit(size).parallel().forEach(x -> {counter.increment();}); |
492 |
assertEquals(size, counter.sum()); |
493 |
} |
494 |
|
495 |
/** |
496 |
* A sequential unsized stream of ints generates at least 100 values |
497 |
*/ |
498 |
public void testUnsizedIntsCountSeq() { |
499 |
LongAdder counter = new LongAdder(); |
500 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
501 |
long size = 100; |
502 |
r.ints().limit(size).forEach(x -> {counter.increment();}); |
503 |
assertEquals(size, counter.sum()); |
504 |
} |
505 |
|
506 |
/** |
507 |
* A sequential unsized stream of longs generates at least 100 values |
508 |
*/ |
509 |
public void testUnsizedLongsCountSeq() { |
510 |
LongAdder counter = new LongAdder(); |
511 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
512 |
long size = 100; |
513 |
r.longs().limit(size).forEach(x -> {counter.increment();}); |
514 |
assertEquals(size, counter.sum()); |
515 |
} |
516 |
|
517 |
/** |
518 |
* A sequential unsized stream of doubles generates at least 100 values |
519 |
*/ |
520 |
public void testUnsizedDoublesCountSeq() { |
521 |
LongAdder counter = new LongAdder(); |
522 |
ThreadLocalRandom r = ThreadLocalRandom.current(); |
523 |
long size = 100; |
524 |
r.doubles().limit(size).forEach(x -> {counter.increment();}); |
525 |
assertEquals(size, counter.sum()); |
526 |
} |
527 |
|
528 |
} |