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/*
* 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.
*/
package jsr166;
import java.util.concurrent.atomic.AtomicStampedReference;
import junit.framework.Test;
import junit.framework.TestSuite;
public class AtomicStampedReferenceTest extends JSR166TestCase {
// android-note: Removed because the CTS runner does a bad job of
// retrying tests that have suite() declarations.
//
// public static void main(String[] args) {
// main(suite(), args);
// }
// public static Test suite() {
// return new TestSuite(...);
// }
/**
* 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]);
}
}
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