369 lines
12 KiB
Java
369 lines
12 KiB
Java
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/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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* This file is available under and governed by the GNU General Public
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* License version 2 only, as published by the Free Software Foundation.
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* However, the following notice accompanied the original version of this
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* file:
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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 java.util.concurrent.ThreadLocalRandom;
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import java.util.concurrent.atomic.AtomicLong;
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import java.util.concurrent.atomic.AtomicReference;
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import junit.framework.Test;
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import junit.framework.TestSuite;
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public class ThreadLocalRandomTest extends JSR166TestCase {
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public static void main(String[] args) {
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main(suite(), args);
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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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* 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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// max numbers of calls to detect getting stuck on one value
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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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// max sampled long bound
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static final long MAX_LONG_BOUND = (1L << 42);
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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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* 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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* 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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* 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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* 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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* 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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* 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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* 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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* nextInt(non-positive) throws IllegalArgumentException
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*/
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public void testNextIntBoundNonPositive() {
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ThreadLocalRandom rnd = ThreadLocalRandom.current();
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for (int bound : new int[] { 0, -17, Integer.MIN_VALUE }) {
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try {
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rnd.nextInt(bound);
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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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int[][] badBoundss = {
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{ 17, 2 },
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{ -42, -42 },
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{ Integer.MAX_VALUE, Integer.MIN_VALUE },
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};
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ThreadLocalRandom rnd = ThreadLocalRandom.current();
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for (int[] badBounds : badBoundss) {
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try {
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rnd.nextInt(badBounds[0], badBounds[1]);
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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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* 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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* nextLong(non-positive) throws IllegalArgumentException
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*/
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public void testNextLongBoundNonPositive() {
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ThreadLocalRandom rnd = ThreadLocalRandom.current();
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for (long bound : new long[] { 0L, -17L, Long.MIN_VALUE }) {
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try {
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rnd.nextLong(bound);
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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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long[][] badBoundss = {
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{ 17L, 2L },
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{ -42L, -42L },
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{ Long.MAX_VALUE, Long.MIN_VALUE },
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};
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ThreadLocalRandom rnd = ThreadLocalRandom.current();
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for (long[] badBounds : badBoundss) {
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try {
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rnd.nextLong(badBounds[0], badBounds[1]);
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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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* 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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* nextDouble(non-positive) throws IllegalArgumentException
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*/
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public void testNextDoubleBoundNonPositive() {
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ThreadLocalRandom rnd = ThreadLocalRandom.current();
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double[] badBounds = {
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0.0d,
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-17.0d,
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-Double.MIN_VALUE,
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Double.NEGATIVE_INFINITY,
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Double.NaN,
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};
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for (double bound : badBounds) {
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try {
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rnd.nextDouble(bound);
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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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* 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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* 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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long firstRand = 0;
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ThreadLocalRandom firstThreadLocalRandom = null;
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Runnable 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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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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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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