| 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 |
*/ |
| 6 |
|
| 7 |
import java.util.concurrent.CyclicBarrier; |
| 8 |
import java.util.concurrent.Executors; |
| 9 |
import java.util.concurrent.ExecutorService; |
| 10 |
import java.util.concurrent.atomic.LongAdder; |
| 11 |
|
| 12 |
import junit.framework.Test; |
| 13 |
import junit.framework.TestSuite; |
| 14 |
|
| 15 |
public class LongAdderTest extends JSR166TestCase { |
| 16 |
public static void main(String[] args) { |
| 17 |
main(suite(), args); |
| 18 |
} |
| 19 |
public static Test suite() { |
| 20 |
return new TestSuite(LongAdderTest.class); |
| 21 |
} |
| 22 |
|
| 23 |
/** |
| 24 |
* default constructed initializes to zero |
| 25 |
*/ |
| 26 |
public void testConstructor() { |
| 27 |
LongAdder ai = new LongAdder(); |
| 28 |
assertEquals(0, ai.sum()); |
| 29 |
} |
| 30 |
|
| 31 |
/** |
| 32 |
* add adds given value to current, and sum returns current value |
| 33 |
*/ |
| 34 |
public void testAddAndSum() { |
| 35 |
LongAdder ai = new LongAdder(); |
| 36 |
ai.add(2); |
| 37 |
assertEquals(2, ai.sum()); |
| 38 |
ai.add(-4); |
| 39 |
assertEquals(-2, ai.sum()); |
| 40 |
} |
| 41 |
|
| 42 |
/** |
| 43 |
* decrement decrements and sum returns current value |
| 44 |
*/ |
| 45 |
public void testDecrementAndSum() { |
| 46 |
LongAdder ai = new LongAdder(); |
| 47 |
ai.decrement(); |
| 48 |
assertEquals(-1, ai.sum()); |
| 49 |
ai.decrement(); |
| 50 |
assertEquals(-2, ai.sum()); |
| 51 |
} |
| 52 |
|
| 53 |
/** |
| 54 |
* incrementAndGet increments and returns current value |
| 55 |
*/ |
| 56 |
public void testIncrementAndSum() { |
| 57 |
LongAdder ai = new LongAdder(); |
| 58 |
ai.increment(); |
| 59 |
assertEquals(1, ai.sum()); |
| 60 |
ai.increment(); |
| 61 |
assertEquals(2, ai.sum()); |
| 62 |
} |
| 63 |
|
| 64 |
/** |
| 65 |
* reset() causes subsequent sum() to return zero |
| 66 |
*/ |
| 67 |
public void testReset() { |
| 68 |
LongAdder ai = new LongAdder(); |
| 69 |
ai.add(2); |
| 70 |
assertEquals(2, ai.sum()); |
| 71 |
ai.reset(); |
| 72 |
assertEquals(0, ai.sum()); |
| 73 |
} |
| 74 |
|
| 75 |
/** |
| 76 |
* sumThenReset() returns sum; subsequent sum() returns zero |
| 77 |
*/ |
| 78 |
public void testSumThenReset() { |
| 79 |
LongAdder ai = new LongAdder(); |
| 80 |
ai.add(2); |
| 81 |
assertEquals(2, ai.sum()); |
| 82 |
assertEquals(2, ai.sumThenReset()); |
| 83 |
assertEquals(0, ai.sum()); |
| 84 |
} |
| 85 |
|
| 86 |
/** |
| 87 |
* a deserialized/reserialized adder holds same value |
| 88 |
*/ |
| 89 |
public void testSerialization() throws Exception { |
| 90 |
LongAdder x = new LongAdder(); |
| 91 |
LongAdder y = serialClone(x); |
| 92 |
assertNotSame(x, y); |
| 93 |
x.add(-22); |
| 94 |
LongAdder z = serialClone(x); |
| 95 |
assertNotSame(y, z); |
| 96 |
assertEquals(-22, x.sum()); |
| 97 |
assertEquals(0, y.sum()); |
| 98 |
assertEquals(-22, z.sum()); |
| 99 |
} |
| 100 |
|
| 101 |
/** |
| 102 |
* toString returns current value. |
| 103 |
*/ |
| 104 |
public void testToString() { |
| 105 |
LongAdder ai = new LongAdder(); |
| 106 |
assertEquals("0", ai.toString()); |
| 107 |
ai.increment(); |
| 108 |
assertEquals(Long.toString(1), ai.toString()); |
| 109 |
} |
| 110 |
|
| 111 |
/** |
| 112 |
* intValue returns current value. |
| 113 |
*/ |
| 114 |
public void testIntValue() { |
| 115 |
LongAdder ai = new LongAdder(); |
| 116 |
assertEquals(0, ai.intValue()); |
| 117 |
ai.increment(); |
| 118 |
assertEquals(1, ai.intValue()); |
| 119 |
} |
| 120 |
|
| 121 |
/** |
| 122 |
* longValue returns current value. |
| 123 |
*/ |
| 124 |
public void testLongValue() { |
| 125 |
LongAdder ai = new LongAdder(); |
| 126 |
assertEquals(0, ai.longValue()); |
| 127 |
ai.increment(); |
| 128 |
assertEquals(1, ai.longValue()); |
| 129 |
} |
| 130 |
|
| 131 |
/** |
| 132 |
* floatValue returns current value. |
| 133 |
*/ |
| 134 |
public void testFloatValue() { |
| 135 |
LongAdder ai = new LongAdder(); |
| 136 |
assertEquals(0.0f, ai.floatValue()); |
| 137 |
ai.increment(); |
| 138 |
assertEquals(1.0f, ai.floatValue()); |
| 139 |
} |
| 140 |
|
| 141 |
/** |
| 142 |
* doubleValue returns current value. |
| 143 |
*/ |
| 144 |
public void testDoubleValue() { |
| 145 |
LongAdder ai = new LongAdder(); |
| 146 |
assertEquals(0.0, ai.doubleValue()); |
| 147 |
ai.increment(); |
| 148 |
assertEquals(1.0, ai.doubleValue()); |
| 149 |
} |
| 150 |
|
| 151 |
/** |
| 152 |
* adds by multiple threads produce correct sum |
| 153 |
*/ |
| 154 |
public void testAddAndSumMT() throws Throwable { |
| 155 |
final int incs = 1000000; |
| 156 |
final int nthreads = 4; |
| 157 |
final ExecutorService pool = Executors.newCachedThreadPool(); |
| 158 |
LongAdder a = new LongAdder(); |
| 159 |
CyclicBarrier barrier = new CyclicBarrier(nthreads + 1); |
| 160 |
for (int i = 0; i < nthreads; ++i) |
| 161 |
pool.execute(new AdderTask(a, barrier, incs)); |
| 162 |
barrier.await(); |
| 163 |
barrier.await(); |
| 164 |
long total = (long)nthreads * incs; |
| 165 |
long sum = a.sum(); |
| 166 |
assertEquals(sum, total); |
| 167 |
pool.shutdown(); |
| 168 |
} |
| 169 |
|
| 170 |
static final class AdderTask implements Runnable { |
| 171 |
final LongAdder adder; |
| 172 |
final CyclicBarrier barrier; |
| 173 |
final int incs; |
| 174 |
volatile long result; |
| 175 |
AdderTask(LongAdder adder, CyclicBarrier barrier, int incs) { |
| 176 |
this.adder = adder; |
| 177 |
this.barrier = barrier; |
| 178 |
this.incs = incs; |
| 179 |
} |
| 180 |
|
| 181 |
public void run() { |
| 182 |
try { |
| 183 |
barrier.await(); |
| 184 |
LongAdder a = adder; |
| 185 |
for (int i = 0; i < incs; ++i) |
| 186 |
a.add(1L); |
| 187 |
result = a.sum(); |
| 188 |
barrier.await(); |
| 189 |
} catch (Throwable t) { throw new Error(t); } |
| 190 |
} |
| 191 |
} |
| 192 |
|
| 193 |
} |
