| /* |
| * 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 |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * 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); |
| } |
| } |