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/*
* Copyright (c) 2014, 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.
*
*/
package rtm;
import com.oracle.java.testlibrary.Utils;
import sun.misc.Unsafe;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
/**
* Test case for busy lock scenario.
* One thread enters the monitor and sleep for a while.
* Another thread is blocked on the same monitor.
*/
public class BusyLock implements CompilableTest, Runnable {
private static final int DEFAULT_TIMEOUT = 1000;
private final CyclicBarrier barrier;
// Following field have to be static in order to avoid escape analysis.
@SuppressWarnings("UnsuedDeclaration")
private static int field = 0;
private static final Unsafe UNSAFE = Utils.getUnsafe();
protected final Object monitor;
protected final int timeout;
public BusyLock() {
this(BusyLock.DEFAULT_TIMEOUT);
}
public BusyLock(int timeout) {
this.timeout = timeout;
this.monitor = new Object();
this.barrier = new CyclicBarrier(2);
}
@Override
public void run() {
try {
// wait until forceAbort leave monitor
barrier.await();
if (UNSAFE.tryMonitorEnter(monitor)) {
try {
barrier.await();
Thread.sleep(timeout);
} finally {
UNSAFE.monitorExit(monitor);
}
} else {
throw new RuntimeException("Monitor should be entered by " +
"::run() first.");
}
} catch (InterruptedException | BrokenBarrierException e) {
throw new RuntimeException("Synchronization error happened.", e);
}
}
public void syncAndTest() {
try {
barrier.await();
// wait until monitor is locked by a ::run method
barrier.await();
} catch (InterruptedException | BrokenBarrierException e) {
throw new RuntimeException("Synchronization error happened.", e);
}
test();
}
public void test() {
synchronized(monitor) {
BusyLock.field++;
}
}
@Override
public String getMethodWithLockName() {
return this.getClass().getName() + "::test";
}
@Override
public String[] getMethodsToCompileNames() {
return new String[] { getMethodWithLockName() };
}
/**
* Usage:
* BusyLock [ <inflate monitor> [ <timeout> ] ]
*
* Default values are:
* <ul>
* <li>inflate monitor = {@code true}</li>
* <li>timeout = {@code BusyLock.DEFAULT_TIMEOUT}</li>
* </ul>
*/
public static void main(String args[]) throws Exception {
int timeoutValue = BusyLock.DEFAULT_TIMEOUT;
boolean inflateMonitor = true;
if (args.length > 0 ) {
inflateMonitor = Boolean.valueOf(args[0]);
if (args.length > 1) {
timeoutValue = Integer.valueOf(args[1]);
}
}
BusyLock busyLock = new BusyLock(timeoutValue);
if (inflateMonitor) {
AbortProvoker.inflateMonitor(busyLock.monitor);
}
Thread t = new Thread(busyLock);
t.start();
busyLock.syncAndTest();
t.join();
}
}
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