/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
/*
* @test
* @bug 6801020 6803402
* @summary Try to tickle race conditions in
* AbstractQueuedSynchronizer "shared" code
*/
import java.util.concurrent.Semaphore;
public class RacingReleases {
/** Increase this for better chance of tickling races */
static final int iterations = 1000;
public static void test(final boolean fair,
final boolean interruptibly)
throws Throwable {
for (int i = 0; i < iterations; i++) {
final Semaphore sem = new Semaphore(0, fair);
final Throwable[] badness = new Throwable[1];
Runnable blocker = interruptibly ?
new Runnable() {
public void run() {
try {
sem.acquire();
} catch (Throwable t) {
badness[0] = t;
throw new Error(t);
}}}
:
new Runnable() {
public void run() {
try {
sem.acquireUninterruptibly();
} catch (Throwable t) {
badness[0] = t;
throw new Error(t);
}}};
Thread b1 = new Thread(blocker);
Thread b2 = new Thread(blocker);
Runnable signaller = new Runnable() {
public void run() {
try {
sem.release();
} catch (Throwable t) {
badness[0] = t;
throw new Error(t);
}}};
Thread s1 = new Thread(signaller);
Thread s2 = new Thread(signaller);
Thread[] threads = { b1, b2, s1, s2 };
java.util.Collections.shuffle(java.util.Arrays.asList(threads));
for (Thread thread : threads)
thread.start();
for (Thread thread : threads) {
thread.join(60 * 1000);
if (thread.isAlive())
throw new Error
(String.format
("Semaphore stuck: permits %d, thread waiting %s%n",
sem.availablePermits(),
sem.hasQueuedThreads() ? "true" : "false"));
}
if (badness[0] != null)
throw new Error(badness[0]);
if (sem.availablePermits() != 0)
throw new Error(String.valueOf(sem.availablePermits()));
if (sem.hasQueuedThreads())
throw new Error(String.valueOf(sem.hasQueuedThreads()));
if (sem.getQueueLength() != 0)
throw new Error(String.valueOf(sem.getQueueLength()));
if (sem.isFair() != fair)
throw new Error(String.valueOf(sem.isFair()));
}
}
public static void main(String[] args) throws Throwable {
for (boolean fair : new boolean[] { true, false })
for (boolean interruptibly : new boolean[] { true, false })
test(fair, interruptibly);
}
}