/*
* 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/
* Other contributors include Andrew Wright, Jeffrey Hayes,
* Pat Fisher, Mike Judd.
*/
import java.util.concurrent.atomic.AtomicStampedReference;
import junit.framework.Test;
import junit.framework.TestSuite;
public class AtomicStampedReferenceTest extends JSR166TestCase {
public static void main(String[] args) {
main(suite(), args);
}
public static Test suite() {
return new TestSuite(AtomicStampedReferenceTest.class);
}
/**
* constructor initializes to given reference and stamp
*/
public void testConstructor() {
AtomicStampedReference ai = new AtomicStampedReference(one, 0);
assertSame(one, ai.getReference());
assertEquals(0, ai.getStamp());
AtomicStampedReference a2 = new AtomicStampedReference(null, 1);
assertNull(a2.getReference());
assertEquals(1, a2.getStamp());
}
/**
* get returns the last values of reference and stamp set
*/
public void testGetSet() {
int[] mark = new int[1];
AtomicStampedReference ai = new AtomicStampedReference(one, 0);
assertSame(one, ai.getReference());
assertEquals(0, ai.getStamp());
assertSame(one, ai.get(mark));
assertEquals(0, mark[0]);
ai.set(two, 0);
assertSame(two, ai.getReference());
assertEquals(0, ai.getStamp());
assertSame(two, ai.get(mark));
assertEquals(0, mark[0]);
ai.set(one, 1);
assertSame(one, ai.getReference());
assertEquals(1, ai.getStamp());
assertSame(one, ai.get(mark));
assertEquals(1, mark[0]);
}
/**
* attemptStamp succeeds in single thread
*/
public void testAttemptStamp() {
int[] mark = new int[1];
AtomicStampedReference ai = new AtomicStampedReference(one, 0);
assertEquals(0, ai.getStamp());
assertTrue(ai.attemptStamp(one, 1));
assertEquals(1, ai.getStamp());
assertSame(one, ai.get(mark));
assertEquals(1, mark[0]);
}
/**
* compareAndSet succeeds in changing values if equal to expected reference
* and stamp else fails
*/
public void testCompareAndSet() {
int[] mark = new int[1];
AtomicStampedReference ai = new AtomicStampedReference(one, 0);
assertSame(one, ai.get(mark));
assertEquals(0, ai.getStamp());
assertEquals(0, mark[0]);
assertTrue(ai.compareAndSet(one, two, 0, 0));
assertSame(two, ai.get(mark));
assertEquals(0, mark[0]);
assertTrue(ai.compareAndSet(two, m3, 0, 1));
assertSame(m3, ai.get(mark));
assertEquals(1, mark[0]);
assertFalse(ai.compareAndSet(two, m3, 1, 1));
assertSame(m3, ai.get(mark));
assertEquals(1, mark[0]);
}
/**
* compareAndSet in one thread enables another waiting for reference value
* to succeed
*/
public void testCompareAndSetInMultipleThreads() throws Exception {
final AtomicStampedReference ai = new AtomicStampedReference(one, 0);
Thread t = new Thread(new CheckedRunnable() {
public void realRun() {
while (!ai.compareAndSet(two, three, 0, 0))
Thread.yield();
}});
t.start();
assertTrue(ai.compareAndSet(one, two, 0, 0));
t.join(LONG_DELAY_MS);
assertFalse(t.isAlive());
assertSame(three, ai.getReference());
assertEquals(0, ai.getStamp());
}
/**
* compareAndSet in one thread enables another waiting for stamp value
* to succeed
*/
public void testCompareAndSetInMultipleThreads2() throws Exception {
final AtomicStampedReference ai = new AtomicStampedReference(one, 0);
Thread t = new Thread(new CheckedRunnable() {
public void realRun() {
while (!ai.compareAndSet(one, one, 1, 2))
Thread.yield();
}});
t.start();
assertTrue(ai.compareAndSet(one, one, 0, 1));
t.join(LONG_DELAY_MS);
assertFalse(t.isAlive());
assertSame(one, ai.getReference());
assertEquals(2, ai.getStamp());
}
/**
* repeated weakCompareAndSet succeeds in changing values when equal
* to expected
*/
public void testWeakCompareAndSet() {
int[] mark = new int[1];
AtomicStampedReference ai = new AtomicStampedReference(one, 0);
assertSame(one, ai.get(mark));
assertEquals(0, ai.getStamp());
assertEquals(0, mark[0]);
do {} while (!ai.weakCompareAndSet(one, two, 0, 0));
assertSame(two, ai.get(mark));
assertEquals(0, mark[0]);
do {} while (!ai.weakCompareAndSet(two, m3, 0, 1));
assertSame(m3, ai.get(mark));
assertEquals(1, mark[0]);
}
}