| /* |
| * Copyright (c) 2006, 2007, Oracle and/or its affiliates. All rights reserved. |
| * 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. |
| */ |
| |
| /* |
| * @test |
| * @bug 6503247 6574123 |
| * @summary Test resilience to tryAcquire methods that throw |
| * @author Martin Buchholz |
| */ |
| |
| import java.util.*; |
| import java.util.concurrent.*; |
| import java.util.concurrent.locks.*; |
| |
| /** |
| * This uses a variant of the standard Mutex demo, except with a |
| * tryAcquire method that randomly throws various Throwable |
| * subclasses. |
| */ |
| @SuppressWarnings({"deprecation", "serial"}) |
| public class FlakyMutex implements Lock { |
| static class MyError extends Error {} |
| static class MyException extends Exception {} |
| static class MyRuntimeException extends RuntimeException {} |
| |
| static final Random rnd = new Random(); |
| |
| static void maybeThrow() { |
| switch (rnd.nextInt(10)) { |
| case 0: throw new MyError(); |
| case 1: throw new MyRuntimeException(); |
| case 2: Thread.currentThread().stop(new MyException()); break; |
| default: /* Do nothing */ break; |
| } |
| } |
| |
| static void checkThrowable(Throwable t) { |
| check((t instanceof MyError) || |
| (t instanceof MyException) || |
| (t instanceof MyRuntimeException)); |
| } |
| |
| static void realMain(String[] args) throws Throwable { |
| final int nThreads = 3; |
| final CyclicBarrier barrier = new CyclicBarrier(nThreads + 1); |
| final FlakyMutex m = new FlakyMutex(); |
| final ExecutorService es = Executors.newFixedThreadPool(nThreads); |
| for (int i = 0; i < nThreads; i++) { |
| es.submit(new Runnable() { public void run() { |
| try { |
| barrier.await(); |
| for (int i = 0; i < 10000; i++) { |
| for (;;) { |
| try { m.lock(); break; } |
| catch (Throwable t) { checkThrowable(t); } |
| } |
| |
| try { check (! m.tryLock()); } |
| catch (Throwable t) { checkThrowable(t); } |
| |
| try { check (! m.tryLock(1, TimeUnit.MICROSECONDS)); } |
| catch (Throwable t) { checkThrowable(t); } |
| |
| m.unlock(); |
| } |
| } catch (Throwable t) { unexpected(t); }}});} |
| barrier.await(); |
| es.shutdown(); |
| check(es.awaitTermination(10, TimeUnit.SECONDS)); |
| } |
| |
| private static class FlakySync extends AbstractQueuedLongSynchronizer { |
| private static final long serialVersionUID = -1L; |
| |
| public boolean isHeldExclusively() { return getState() == 1; } |
| |
| public boolean tryAcquire(long acquires) { |
| // Sneak in some tests for queue state |
| if (hasQueuedPredecessors()) |
| check(getFirstQueuedThread() != Thread.currentThread()); |
| if (getFirstQueuedThread() == Thread.currentThread()) { |
| check(hasQueuedThreads()); |
| check(!hasQueuedPredecessors()); |
| } else { |
| // Might be true, but only transiently |
| do {} while (hasQueuedPredecessors() != hasQueuedThreads()); |
| } |
| |
| maybeThrow(); |
| return compareAndSetState(0, 1); |
| } |
| |
| public boolean tryRelease(long releases) { |
| setState(0); |
| return true; |
| } |
| |
| Condition newCondition() { return new ConditionObject(); } |
| } |
| |
| private final FlakySync sync = new FlakySync(); |
| public void lock() { sync.acquire(1); } |
| public boolean tryLock() { return sync.tryAcquire(1); } |
| public void lockInterruptibly() throws InterruptedException { |
| sync.acquireInterruptibly(1); |
| } |
| public boolean tryLock(long timeout, TimeUnit unit) throws InterruptedException { |
| return sync.tryAcquireNanos(1, unit.toNanos(timeout)); |
| } |
| public void unlock() { sync.release(1); } |
| public Condition newCondition() { return sync.newCondition(); } |
| public boolean isLocked() { return sync.isHeldExclusively(); } |
| public boolean hasQueuedThreads() { return sync.hasQueuedThreads(); } |
| |
| //--------------------- Infrastructure --------------------------- |
| static volatile int passed = 0, failed = 0; |
| static void pass() {passed++;} |
| static void fail() {failed++; Thread.dumpStack();} |
| static void fail(String msg) {System.out.println(msg); fail();} |
| static void unexpected(Throwable t) {failed++; t.printStackTrace();} |
| static void check(boolean cond) {if (cond) pass(); else fail();} |
| static void equal(Object x, Object y) { |
| if (x == null ? y == null : x.equals(y)) pass(); |
| else fail(x + " not equal to " + y);} |
| public static void main(String[] args) throws Throwable { |
| try {realMain(args);} catch (Throwable t) {unexpected(t);} |
| System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed); |
| if (failed > 0) throw new AssertionError("Some tests failed");} |
| } |