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/publicdomain/zero/1.0/ 5 * Other contributors include Andrew Wright, Jeffrey Hayes, 6 * Pat Fisher, Mike Judd. 7 */ 8 9 package jsr166; 10 11 import java.util.concurrent.atomic.AtomicStampedReference; 12 13 import junit.framework.Test; 14 import junit.framework.TestSuite; 15 16 public class AtomicStampedReferenceTest extends JSR166TestCase { 17 // android-note: Removed because the CTS runner does a bad job of 18 // retrying tests that have suite() declarations. 19 // 20 // public static void main(String[] args) { 21 // main(suite(), args); 22 // } 23 // public static Test suite() { 24 // return new TestSuite(AtomicStampedReferenceTest.class); 25 // } 26 27 /** 28 * constructor initializes to given reference and stamp 29 */ 30 public void testConstructor() { 31 AtomicStampedReference ai = new AtomicStampedReference(one, 0); 32 assertSame(one, ai.getReference()); 33 assertEquals(0, ai.getStamp()); 34 AtomicStampedReference a2 = new AtomicStampedReference(null, 1); 35 assertNull(a2.getReference()); 36 assertEquals(1, a2.getStamp()); 37 } 38 39 /** 40 * get returns the last values of reference and stamp set 41 */ 42 public void testGetSet() { 43 int[] mark = new int[1]; 44 AtomicStampedReference ai = new AtomicStampedReference(one, 0); 45 assertSame(one, ai.getReference()); 46 assertEquals(0, ai.getStamp()); 47 assertSame(one, ai.get(mark)); 48 assertEquals(0, mark[0]); 49 ai.set(two, 0); 50 assertSame(two, ai.getReference()); 51 assertEquals(0, ai.getStamp()); 52 assertSame(two, ai.get(mark)); 53 assertEquals(0, mark[0]); 54 ai.set(one, 1); 55 assertSame(one, ai.getReference()); 56 assertEquals(1, ai.getStamp()); 57 assertSame(one, ai.get(mark)); 58 assertEquals(1, mark[0]); 59 } 60 61 /** 62 * attemptStamp succeeds in single thread 63 */ 64 public void testAttemptStamp() { 65 int[] mark = new int[1]; 66 AtomicStampedReference ai = new AtomicStampedReference(one, 0); 67 assertEquals(0, ai.getStamp()); 68 assertTrue(ai.attemptStamp(one, 1)); 69 assertEquals(1, ai.getStamp()); 70 assertSame(one, ai.get(mark)); 71 assertEquals(1, mark[0]); 72 } 73 74 /** 75 * compareAndSet succeeds in changing values if equal to expected reference 76 * and stamp else fails 77 */ 78 public void testCompareAndSet() { 79 int[] mark = new int[1]; 80 AtomicStampedReference ai = new AtomicStampedReference(one, 0); 81 assertSame(one, ai.get(mark)); 82 assertEquals(0, ai.getStamp()); 83 assertEquals(0, mark[0]); 84 85 assertTrue(ai.compareAndSet(one, two, 0, 0)); 86 assertSame(two, ai.get(mark)); 87 assertEquals(0, mark[0]); 88 89 assertTrue(ai.compareAndSet(two, m3, 0, 1)); 90 assertSame(m3, ai.get(mark)); 91 assertEquals(1, mark[0]); 92 93 assertFalse(ai.compareAndSet(two, m3, 1, 1)); 94 assertSame(m3, ai.get(mark)); 95 assertEquals(1, mark[0]); 96 } 97 98 /** 99 * compareAndSet in one thread enables another waiting for reference value 100 * to succeed 101 */ 102 public void testCompareAndSetInMultipleThreads() throws Exception { 103 final AtomicStampedReference ai = new AtomicStampedReference(one, 0); 104 Thread t = new Thread(new CheckedRunnable() { 105 public void realRun() { 106 while (!ai.compareAndSet(two, three, 0, 0)) 107 Thread.yield(); 108 }}); 109 110 t.start(); 111 assertTrue(ai.compareAndSet(one, two, 0, 0)); 112 t.join(LONG_DELAY_MS); 113 assertFalse(t.isAlive()); 114 assertSame(three, ai.getReference()); 115 assertEquals(0, ai.getStamp()); 116 } 117 118 /** 119 * compareAndSet in one thread enables another waiting for stamp value 120 * to succeed 121 */ 122 public void testCompareAndSetInMultipleThreads2() throws Exception { 123 final AtomicStampedReference ai = new AtomicStampedReference(one, 0); 124 Thread t = new Thread(new CheckedRunnable() { 125 public void realRun() { 126 while (!ai.compareAndSet(one, one, 1, 2)) 127 Thread.yield(); 128 }}); 129 130 t.start(); 131 assertTrue(ai.compareAndSet(one, one, 0, 1)); 132 t.join(LONG_DELAY_MS); 133 assertFalse(t.isAlive()); 134 assertSame(one, ai.getReference()); 135 assertEquals(2, ai.getStamp()); 136 } 137 138 /** 139 * repeated weakCompareAndSet succeeds in changing values when equal 140 * to expected 141 */ 142 public void testWeakCompareAndSet() { 143 int[] mark = new int[1]; 144 AtomicStampedReference ai = new AtomicStampedReference(one, 0); 145 assertSame(one, ai.get(mark)); 146 assertEquals(0, ai.getStamp()); 147 assertEquals(0, mark[0]); 148 149 do {} while (!ai.weakCompareAndSet(one, two, 0, 0)); 150 assertSame(two, ai.get(mark)); 151 assertEquals(0, mark[0]); 152 153 do {} while (!ai.weakCompareAndSet(two, m3, 0, 1)); 154 assertSame(m3, ai.get(mark)); 155 assertEquals(1, mark[0]); 156 } 157 158 } 159
