| 1 |
/* |
| 2 |
* Written by Doug Lea with assistance from members of JCP JSR-166 |
| 3 |
* Expert Group and released to the public domain, as explained at |
| 4 |
* http://creativecommons.org/licenses/publicdomain |
| 5 |
* Other contributors include Andrew Wright, Jeffrey Hayes, |
| 6 |
* Pat Fisher, Mike Judd. |
| 7 |
*/ |
| 8 |
|
| 9 |
import junit.framework.*; |
| 10 |
import java.util.concurrent.atomic.*; |
| 11 |
|
| 12 |
public class AtomicStampedReferenceTest extends JSR166TestCase { |
| 13 |
public static void main (String[] args) { |
| 14 |
junit.textui.TestRunner.run (suite()); |
| 15 |
} |
| 16 |
public static Test suite() { |
| 17 |
return new TestSuite(AtomicStampedReferenceTest.class); |
| 18 |
} |
| 19 |
|
| 20 |
/** |
| 21 |
* constructor initializes to given reference and stamp |
| 22 |
*/ |
| 23 |
public void testConstructor() { |
| 24 |
AtomicStampedReference ai = new AtomicStampedReference(one, 0); |
| 25 |
assertEquals(one,ai.getReference()); |
| 26 |
assertEquals(0, ai.getStamp()); |
| 27 |
AtomicStampedReference a2 = new AtomicStampedReference(null, 1); |
| 28 |
assertNull(a2.getReference()); |
| 29 |
assertEquals(1, a2.getStamp()); |
| 30 |
|
| 31 |
} |
| 32 |
|
| 33 |
/** |
| 34 |
* get returns the last values of reference and stamp set |
| 35 |
*/ |
| 36 |
public void testGetSet() { |
| 37 |
int[] mark = new int[1]; |
| 38 |
AtomicStampedReference ai = new AtomicStampedReference(one, 0); |
| 39 |
assertEquals(one,ai.getReference()); |
| 40 |
assertEquals(0, ai.getStamp()); |
| 41 |
assertEquals(one, ai.get(mark)); |
| 42 |
assertEquals(0, mark[0]); |
| 43 |
ai.set(two, 0); |
| 44 |
assertEquals(two,ai.getReference()); |
| 45 |
assertEquals(0, ai.getStamp()); |
| 46 |
assertEquals(two, ai.get(mark)); |
| 47 |
assertEquals(0, mark[0]); |
| 48 |
ai.set(one, 1); |
| 49 |
assertEquals(one,ai.getReference()); |
| 50 |
assertEquals(1, ai.getStamp()); |
| 51 |
assertEquals(one, ai.get(mark)); |
| 52 |
assertEquals(1,mark[0]); |
| 53 |
} |
| 54 |
|
| 55 |
/** |
| 56 |
* attemptStamp succeeds in single thread |
| 57 |
*/ |
| 58 |
public void testAttemptStamp() { |
| 59 |
int[] mark = new int[1]; |
| 60 |
AtomicStampedReference ai = new AtomicStampedReference(one, 0); |
| 61 |
assertEquals(0, ai.getStamp()); |
| 62 |
assertTrue(ai.attemptStamp(one, 1)); |
| 63 |
assertEquals(1, ai.getStamp()); |
| 64 |
assertEquals(one, ai.get(mark)); |
| 65 |
assertEquals(1, mark[0]); |
| 66 |
} |
| 67 |
|
| 68 |
/** |
| 69 |
* compareAndSet succeeds in changing values if equal to expected reference |
| 70 |
* and stamp else fails |
| 71 |
*/ |
| 72 |
public void testCompareAndSet() { |
| 73 |
int[] mark = new int[1]; |
| 74 |
AtomicStampedReference ai = new AtomicStampedReference(one, 0); |
| 75 |
assertEquals(one, ai.get(mark)); |
| 76 |
assertEquals(0, ai.getStamp()); |
| 77 |
assertEquals(0, mark[0]); |
| 78 |
|
| 79 |
assertTrue(ai.compareAndSet(one, two, 0, 0)); |
| 80 |
assertEquals(two, ai.get(mark)); |
| 81 |
assertEquals(0, mark[0]); |
| 82 |
|
| 83 |
assertTrue(ai.compareAndSet(two, m3, 0, 1)); |
| 84 |
assertEquals(m3, ai.get(mark)); |
| 85 |
assertEquals(1, mark[0]); |
| 86 |
|
| 87 |
assertFalse(ai.compareAndSet(two, m3, 1, 1)); |
| 88 |
assertEquals(m3, ai.get(mark)); |
| 89 |
assertEquals(1, mark[0]); |
| 90 |
} |
| 91 |
|
| 92 |
/** |
| 93 |
* compareAndSet in one thread enables another waiting for reference value |
| 94 |
* to succeed |
| 95 |
*/ |
| 96 |
public void testCompareAndSetInMultipleThreads() throws Exception { |
| 97 |
final AtomicStampedReference ai = new AtomicStampedReference(one, 0); |
| 98 |
Thread t = new Thread(new CheckedRunnable() { |
| 99 |
public void realRun() { |
| 100 |
while (!ai.compareAndSet(two, three, 0, 0)) |
| 101 |
Thread.yield(); |
| 102 |
}}); |
| 103 |
|
| 104 |
t.start(); |
| 105 |
assertTrue(ai.compareAndSet(one, two, 0, 0)); |
| 106 |
t.join(LONG_DELAY_MS); |
| 107 |
assertFalse(t.isAlive()); |
| 108 |
assertEquals(ai.getReference(), three); |
| 109 |
assertEquals(ai.getStamp(), 0); |
| 110 |
} |
| 111 |
|
| 112 |
/** |
| 113 |
* compareAndSet in one thread enables another waiting for stamp value |
| 114 |
* to succeed |
| 115 |
*/ |
| 116 |
public void testCompareAndSetInMultipleThreads2() throws Exception { |
| 117 |
final AtomicStampedReference ai = new AtomicStampedReference(one, 0); |
| 118 |
Thread t = new Thread(new CheckedRunnable() { |
| 119 |
public void realRun() { |
| 120 |
while (!ai.compareAndSet(one, one, 1, 2)) |
| 121 |
Thread.yield(); |
| 122 |
}}); |
| 123 |
|
| 124 |
t.start(); |
| 125 |
assertTrue(ai.compareAndSet(one, one, 0, 1)); |
| 126 |
t.join(LONG_DELAY_MS); |
| 127 |
assertFalse(t.isAlive()); |
| 128 |
assertEquals(ai.getReference(), one); |
| 129 |
assertEquals(ai.getStamp(), 2); |
| 130 |
} |
| 131 |
|
| 132 |
/** |
| 133 |
* repeated weakCompareAndSet succeeds in changing values when equal |
| 134 |
* to expected |
| 135 |
*/ |
| 136 |
public void testWeakCompareAndSet() { |
| 137 |
int[] mark = new int[1]; |
| 138 |
AtomicStampedReference ai = new AtomicStampedReference(one, 0); |
| 139 |
assertEquals(one, ai.get(mark)); |
| 140 |
assertEquals(0, ai.getStamp ()); |
| 141 |
assertEquals(0, mark[0]); |
| 142 |
|
| 143 |
while (!ai.weakCompareAndSet(one, two, 0, 0)); |
| 144 |
assertEquals(two, ai.get(mark)); |
| 145 |
assertEquals(0, mark[0]); |
| 146 |
|
| 147 |
while (!ai.weakCompareAndSet(two, m3, 0, 1)); |
| 148 |
assertEquals(m3, ai.get(mark)); |
| 149 |
assertEquals(1, mark[0]); |
| 150 |
} |
| 151 |
|
| 152 |
} |
