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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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* Other contributors include Andrew Wright, Jeffrey Hayes, |
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* Pat Fisher, Mike Judd. |
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*/ |
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|
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import java.util.concurrent.atomic.AtomicStampedReference; |
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|
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import junit.framework.Test; |
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import junit.framework.TestSuite; |
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|
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public class AtomicStampedReferenceTest extends JSR166TestCase { |
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public static void main(String[] args) { |
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main(suite(), args); |
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} |
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public static Test suite() { |
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return new TestSuite(AtomicStampedReferenceTest.class); |
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} |
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|
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/** |
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* constructor initializes to given reference and stamp |
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*/ |
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public void testConstructor() { |
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AtomicStampedReference<Item> ai = new AtomicStampedReference<>(one, 0); |
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assertSame(one, ai.getReference()); |
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assertEquals(0, ai.getStamp()); |
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AtomicStampedReference<Item> a2 = new AtomicStampedReference<>(null, 1); |
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assertNull(a2.getReference()); |
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assertEquals(1, a2.getStamp()); |
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} |
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|
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/** |
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* get returns the last values of reference and stamp set |
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*/ |
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public void testGetSet() { |
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int[] mark = new int[1]; |
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AtomicStampedReference<Item> ai = new AtomicStampedReference<>(one, 0); |
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assertSame(one, ai.getReference()); |
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assertEquals(0, ai.getStamp()); |
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assertSame(one, ai.get(mark)); |
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assertEquals(0, mark[0]); |
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ai.set(two, 0); |
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assertSame(two, ai.getReference()); |
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assertEquals(0, ai.getStamp()); |
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assertSame(two, ai.get(mark)); |
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assertEquals(0, mark[0]); |
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ai.set(one, 1); |
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assertSame(one, ai.getReference()); |
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assertEquals(1, ai.getStamp()); |
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assertSame(one, ai.get(mark)); |
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assertEquals(1, mark[0]); |
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} |
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|
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/** |
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* attemptStamp succeeds in single thread |
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*/ |
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public void testAttemptStamp() { |
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int[] mark = new int[1]; |
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AtomicStampedReference<Item> ai = new AtomicStampedReference<>(one, 0); |
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assertEquals(0, ai.getStamp()); |
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assertTrue(ai.attemptStamp(one, 1)); |
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assertEquals(1, ai.getStamp()); |
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assertSame(one, ai.get(mark)); |
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assertEquals(1, mark[0]); |
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} |
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|
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/** |
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* compareAndSet succeeds in changing values if equal to expected reference |
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* and stamp else fails |
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*/ |
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public void testCompareAndSet() { |
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int[] mark = new int[1]; |
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AtomicStampedReference<Item> ai = new AtomicStampedReference<>(one, 0); |
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assertSame(one, ai.get(mark)); |
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assertEquals(0, ai.getStamp()); |
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assertEquals(0, mark[0]); |
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|
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assertTrue(ai.compareAndSet(one, two, 0, 0)); |
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assertSame(two, ai.get(mark)); |
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assertEquals(0, mark[0]); |
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|
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assertTrue(ai.compareAndSet(two, minusThree, 0, 1)); |
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assertSame(minusThree, ai.get(mark)); |
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assertEquals(1, mark[0]); |
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|
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assertFalse(ai.compareAndSet(two, minusThree, 1, 1)); |
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assertSame(minusThree, ai.get(mark)); |
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assertEquals(1, mark[0]); |
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} |
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|
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/** |
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* compareAndSet in one thread enables another waiting for reference value |
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* to succeed |
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*/ |
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public void testCompareAndSetInMultipleThreads() throws Exception { |
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final AtomicStampedReference<Item> ai = new AtomicStampedReference<>(one, 0); |
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Thread t = new Thread(new CheckedRunnable() { |
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public void realRun() { |
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while (!ai.compareAndSet(two, three, 0, 0)) |
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Thread.yield(); |
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}}); |
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|
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t.start(); |
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assertTrue(ai.compareAndSet(one, two, 0, 0)); |
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t.join(LONG_DELAY_MS); |
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assertFalse(t.isAlive()); |
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assertSame(three, ai.getReference()); |
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assertEquals(0, ai.getStamp()); |
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} |
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|
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/** |
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* compareAndSet in one thread enables another waiting for stamp value |
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* to succeed |
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*/ |
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public void testCompareAndSetInMultipleThreads2() throws Exception { |
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final AtomicStampedReference<Item> ai = new AtomicStampedReference<>(one, 0); |
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Thread t = new Thread(new CheckedRunnable() { |
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public void realRun() { |
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while (!ai.compareAndSet(one, one, 1, 2)) |
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Thread.yield(); |
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}}); |
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|
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t.start(); |
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assertTrue(ai.compareAndSet(one, one, 0, 1)); |
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t.join(LONG_DELAY_MS); |
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assertFalse(t.isAlive()); |
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assertSame(one, ai.getReference()); |
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assertEquals(2, ai.getStamp()); |
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} |
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|
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/** |
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* repeated weakCompareAndSet succeeds in changing values when equal |
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* to expected |
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*/ |
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public void testWeakCompareAndSet() { |
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int[] mark = new int[1]; |
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AtomicStampedReference<Item> ai = new AtomicStampedReference<>(one, 0); |
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assertSame(one, ai.get(mark)); |
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assertEquals(0, ai.getStamp()); |
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assertEquals(0, mark[0]); |
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|
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do {} while (!ai.weakCompareAndSet(one, two, 0, 0)); |
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assertSame(two, ai.get(mark)); |
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assertEquals(0, mark[0]); |
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|
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do {} while (!ai.weakCompareAndSet(two, minusThree, 0, 1)); |
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assertSame(minusThree, ai.get(mark)); |
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assertEquals(1, mark[0]); |
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} |
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|
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} |
