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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.AtomicReferenceFieldUpdater; |
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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 AtomicReferenceFieldUpdaterTest extends JSR166TestCase { |
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volatile Integer x = null; |
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Object z; |
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Integer w; |
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volatile int i; |
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|
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public static void main(String[] args) { |
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junit.textui.TestRunner.run(suite()); |
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} |
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public static Test suite() { |
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return new TestSuite(AtomicReferenceFieldUpdaterTest.class); |
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} |
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|
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AtomicReferenceFieldUpdater<AtomicReferenceFieldUpdaterTest, Integer> updaterFor(String fieldName) { |
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return AtomicReferenceFieldUpdater.newUpdater |
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(AtomicReferenceFieldUpdaterTest.class, Integer.class, fieldName); |
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} |
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|
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/** |
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* Construction with non-existent field throws RuntimeException |
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*/ |
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public void testConstructor() { |
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try { |
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updaterFor("y"); |
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shouldThrow(); |
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} catch (RuntimeException success) { |
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assertNotNull(success.getCause()); |
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} |
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} |
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|
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/** |
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* construction with field not of given type throws ClassCastException |
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*/ |
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public void testConstructor2() { |
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try { |
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updaterFor("z"); |
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shouldThrow(); |
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} catch (ClassCastException success) {} |
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} |
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|
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/** |
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* Constructor with non-volatile field throws IllegalArgumentException |
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*/ |
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public void testConstructor3() { |
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try { |
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updaterFor("w"); |
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shouldThrow(); |
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} catch (IllegalArgumentException success) {} |
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} |
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|
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/** |
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* Constructor with non-reference field throws ClassCastException |
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*/ |
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public void testConstructor4() { |
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try { |
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updaterFor("i"); |
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shouldThrow(); |
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} catch (ClassCastException success) {} |
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} |
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|
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/** |
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* get returns the last value set or assigned |
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*/ |
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public void testGetSet() { |
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AtomicReferenceFieldUpdater<AtomicReferenceFieldUpdaterTest, Integer> a; |
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a = updaterFor("x"); |
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x = one; |
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assertSame(one, a.get(this)); |
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a.set(this, two); |
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assertSame(two, a.get(this)); |
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a.set(this, m3); |
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assertSame(m3, a.get(this)); |
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} |
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|
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/** |
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* get returns the last value lazySet by same thread |
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*/ |
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public void testGetLazySet() { |
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AtomicReferenceFieldUpdater<AtomicReferenceFieldUpdaterTest, Integer> a; |
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a = updaterFor("x"); |
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x = one; |
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assertSame(one, a.get(this)); |
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a.lazySet(this, two); |
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assertSame(two, a.get(this)); |
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a.lazySet(this, m3); |
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assertSame(m3, a.get(this)); |
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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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AtomicReferenceFieldUpdater<AtomicReferenceFieldUpdaterTest, Integer> a; |
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a = updaterFor("x"); |
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x = one; |
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assertTrue(a.compareAndSet(this, one, two)); |
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assertTrue(a.compareAndSet(this, two, m4)); |
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assertSame(m4, a.get(this)); |
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assertFalse(a.compareAndSet(this, m5, seven)); |
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assertFalse(seven == a.get(this)); |
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assertTrue(a.compareAndSet(this, m4, seven)); |
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assertSame(seven, a.get(this)); |
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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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x = one; |
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final AtomicReferenceFieldUpdater<AtomicReferenceFieldUpdaterTest, Integer> a; |
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a = updaterFor("x"); |
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|
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Thread t = new Thread(new CheckedRunnable() { |
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public void realRun() { |
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while (!a.compareAndSet(AtomicReferenceFieldUpdaterTest.this, 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(a.compareAndSet(this, one, two)); |
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t.join(LONG_DELAY_MS); |
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assertFalse(t.isAlive()); |
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assertSame(three, a.get(this)); |
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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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public void testWeakCompareAndSet() { |
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AtomicReferenceFieldUpdater<AtomicReferenceFieldUpdaterTest, Integer> a; |
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a = updaterFor("x"); |
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x = one; |
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do {} while (!a.weakCompareAndSet(this, one, two)); |
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do {} while (!a.weakCompareAndSet(this, two, m4)); |
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assertSame(m4, a.get(this)); |
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do {} while (!a.weakCompareAndSet(this, m4, seven)); |
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assertSame(seven, a.get(this)); |
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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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AtomicReferenceFieldUpdater<AtomicReferenceFieldUpdaterTest, Integer> a; |
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a = updaterFor("x"); |
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x = one; |
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assertSame(one, a.getAndSet(this, zero)); |
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assertSame(zero, a.getAndSet(this, m10)); |
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assertSame(m10, a.getAndSet(this, 1)); |
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} |
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|
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} |