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/*
* 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/
* Other contributors include Andrew Wright, Jeffrey Hayes,
* Pat Fisher, Mike Judd.
*/
import junit.framework.Test;
import junit.framework.TestSuite;
import java.util.ArrayDeque;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class ReentrantReadWriteLock20Test extends JSR166TestCase {
public static void main(String[] args) {
main(suite(), args);
}
public static Test suite() {
return new TestSuite(ReentrantReadWriteLock20Test.class);
}
public void test66kReadersFair() throws InterruptedException { test66kReaders(true); }
public void test66kReadersUnfair() throws InterruptedException { test66kReaders(false); }
private void test66kReaders(boolean fairness) throws InterruptedException {
final var failure = new AtomicReference<Throwable>();
final var lock = new ReentrantReadWriteLock(fairness);
final var numThreads = 0x10000;
final var threads = new ArrayDeque<Thread>(numThreads);
final var latch = new CountDownLatch(1);
try {
for(int i = 0; i < numThreads && failure.get() == null;++i) {
var t = Thread.ofVirtual().unstarted(() -> {
try {
lock.readLock().lock();
} catch (Throwable ex) {
failure.compareAndSet(null, ex);
return;
}
try {
while (latch.getCount() > 0) {
try {
latch.await();
} catch (InterruptedException ie) {
failure.compareAndSet(null, ie);
}
}
}
finally {
lock.readLock().unlock();
}
});
threads.addLast(t);
t.start();
}
} finally {
latch.countDown(); // Make sure waiters are signalled
Thread next;
while ((next = threads.pollFirst()) != null) {
while (next.isAlive()) {
next.join();
}
}
}
assertEquals(null, failure.get());
}
}
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