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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.AtomicReference; |
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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 AtomicReferenceTest 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(AtomicReferenceTest.class); |
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} |
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|
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/** |
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* constructor initializes to given value |
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*/ |
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public void testConstructor() { |
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AtomicReference<Item> ai = new AtomicReference<>(one); |
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assertSame(one, ai.get()); |
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} |
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|
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/** |
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* default constructed initializes to null |
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*/ |
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public void testConstructor2() { |
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AtomicReference<Item> ai = new AtomicReference<>(); |
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assertNull(ai.get()); |
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} |
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|
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/** |
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* get returns the last value set |
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*/ |
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public void testGetSet() { |
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AtomicReference<Item> ai = new AtomicReference<>(one); |
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assertSame(one, ai.get()); |
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ai.set(two); |
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assertSame(two, ai.get()); |
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ai.set(minusThree); |
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assertSame(minusThree, ai.get()); |
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} |
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|
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/** |
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* get returns the last value lazySet in same thread |
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*/ |
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public void testGetLazySet() { |
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AtomicReference<Item> ai = new AtomicReference<>(one); |
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assertSame(one, ai.get()); |
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ai.lazySet(two); |
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assertSame(two, ai.get()); |
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ai.lazySet(minusThree); |
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assertSame(minusThree, ai.get()); |
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} |
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|
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/** |
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* compareAndSet succeeds in changing value if equal to expected else fails |
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*/ |
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public void testCompareAndSet() { |
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AtomicReference<Item> ai = new AtomicReference<>(one); |
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assertTrue(ai.compareAndSet(one, two)); |
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assertTrue(ai.compareAndSet(two, minusFour)); |
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assertSame(minusFour, ai.get()); |
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assertFalse(ai.compareAndSet(minusFive, seven)); |
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assertSame(minusFour, ai.get()); |
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assertTrue(ai.compareAndSet(minusFour, seven)); |
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assertSame(seven, ai.get()); |
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} |
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|
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/** |
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* compareAndSet in one thread enables another waiting for 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 AtomicReference<Item> ai = new AtomicReference<>(one); |
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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)) |
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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)); |
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t.join(LONG_DELAY_MS); |
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assertFalse(t.isAlive()); |
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assertSame(three, ai.get()); |
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} |
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|
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/** |
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* repeated weakCompareAndSet succeeds in changing value when equal |
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* to expected |
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*/ |
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@SuppressWarnings("deprecation") |
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public void testWeakCompareAndSet() { |
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AtomicReference<Item> ai = new AtomicReference<>(one); |
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do {} while (!ai.weakCompareAndSet(one, two)); |
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do {} while (!ai.weakCompareAndSet(two, minusFour)); |
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assertSame(minusFour, ai.get()); |
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do {} while (!ai.weakCompareAndSet(minusFour, seven)); |
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assertSame(seven, ai.get()); |
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} |
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|
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/** |
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* getAndSet returns previous value and sets to given value |
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*/ |
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public void testGetAndSet() { |
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AtomicReference<Item> ai = new AtomicReference<>(one); |
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assertSame(one, ai.getAndSet(zero)); |
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assertSame(zero, ai.getAndSet(minusTen)); |
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assertSame(minusTen, ai.getAndSet(one)); |
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} |
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|
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/** |
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* a deserialized/reserialized atomic holds same value |
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*/ |
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public void testSerialization() throws Exception { |
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AtomicReference<Item> x = new AtomicReference<>(); |
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AtomicReference<Item> y = serialClone(x); |
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assertNotSame(x, y); |
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x.set(one); |
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AtomicReference<Item> z = serialClone(x); |
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assertNotSame(y, z); |
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assertEquals(one, x.get()); |
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assertNull(y.get()); |
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assertEquals(one, z.get()); |
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} |
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|
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/** |
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* toString returns current value. |
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*/ |
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public void testToString() { |
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AtomicReference<Item> ai = new AtomicReference<>(one); |
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assertEquals(one.toString(), ai.toString()); |
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ai.set(two); |
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assertEquals(two.toString(), ai.toString()); |
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} |
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|
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} |
