| 4 |
|
* http://creativecommons.org/publicdomain/zero/1.0/ |
| 5 |
|
*/ |
| 6 |
|
|
| 7 |
< |
import junit.framework.*; |
| 8 |
< |
import java.util.concurrent.*; |
| 7 |
> |
import java.util.concurrent.Executors; |
| 8 |
> |
import java.util.concurrent.ExecutorService; |
| 9 |
> |
import java.util.concurrent.Phaser; |
| 10 |
> |
import java.util.concurrent.ThreadLocalRandom; |
| 11 |
|
import java.util.concurrent.atomic.LongAccumulator; |
| 12 |
|
|
| 13 |
+ |
import junit.framework.Test; |
| 14 |
+ |
import junit.framework.TestSuite; |
| 15 |
+ |
|
| 16 |
|
public class LongAccumulatorTest extends JSR166TestCase { |
| 17 |
|
public static void main(String[] args) { |
| 18 |
< |
junit.textui.TestRunner.run(suite()); |
| 18 |
> |
main(suite(), args); |
| 19 |
|
} |
| 20 |
|
public static Test suite() { |
| 21 |
|
return new TestSuite(LongAccumulatorTest.class); |
| 22 |
|
} |
| 23 |
|
|
| 24 |
|
/** |
| 25 |
< |
* default constructed initializes to zero |
| 25 |
> |
* new instance initialized to supplied identity |
| 26 |
|
*/ |
| 27 |
|
public void testConstructor() { |
| 28 |
< |
LongAccumulator ai = new LongAccumulator(Long::max, 0L); |
| 29 |
< |
assertEquals(0, ai.get()); |
| 28 |
> |
for (long identity : new long[] { Long.MIN_VALUE, 0, Long.MAX_VALUE }) |
| 29 |
> |
assertEquals(identity, |
| 30 |
> |
new LongAccumulator(Long::max, identity).get()); |
| 31 |
|
} |
| 32 |
|
|
| 33 |
|
/** |
| 34 |
|
* accumulate accumulates given value to current, and get returns current value |
| 35 |
|
*/ |
| 36 |
|
public void testAccumulateAndGet() { |
| 37 |
< |
LongAccumulator ai = new LongAccumulator(Long::max, 0L); |
| 38 |
< |
ai.accumulate(2); |
| 39 |
< |
assertEquals(2, ai.get()); |
| 40 |
< |
ai.accumulate(-4); |
| 41 |
< |
assertEquals(2, ai.get()); |
| 42 |
< |
ai.accumulate(4); |
| 43 |
< |
assertEquals(4, ai.get()); |
| 37 |
> |
LongAccumulator acc = new LongAccumulator(Long::max, 0L); |
| 38 |
> |
acc.accumulate(2); |
| 39 |
> |
assertEquals(2, acc.get()); |
| 40 |
> |
acc.accumulate(-4); |
| 41 |
> |
assertEquals(2, acc.get()); |
| 42 |
> |
acc.accumulate(4); |
| 43 |
> |
assertEquals(4, acc.get()); |
| 44 |
|
} |
| 45 |
|
|
| 46 |
|
/** |
| 47 |
< |
* reset zeroes get |
| 47 |
> |
* reset() causes subsequent get() to return zero |
| 48 |
|
*/ |
| 49 |
|
public void testReset() { |
| 50 |
< |
LongAccumulator ai = new LongAccumulator(Long::max, 0L); |
| 51 |
< |
ai.accumulate(2); |
| 52 |
< |
assertEquals(2, ai.get()); |
| 53 |
< |
ai.reset(); |
| 54 |
< |
assertEquals(0, ai.get()); |
| 50 |
> |
LongAccumulator acc = new LongAccumulator(Long::max, 0L); |
| 51 |
> |
acc.accumulate(2); |
| 52 |
> |
assertEquals(2, acc.get()); |
| 53 |
> |
acc.reset(); |
| 54 |
> |
assertEquals(0, acc.get()); |
| 55 |
|
} |
| 56 |
|
|
| 57 |
|
/** |
| 58 |
< |
* getThenReset returns get then zeros |
| 58 |
> |
* getThenReset() returns current value; subsequent get() returns zero |
| 59 |
|
*/ |
| 60 |
|
public void testGetThenReset() { |
| 61 |
< |
LongAccumulator ai = new LongAccumulator(Long::max, 0L); |
| 62 |
< |
ai.accumulate(2); |
| 63 |
< |
assertEquals(2, ai.get()); |
| 64 |
< |
assertEquals(2, ai.getThenReset()); |
| 65 |
< |
assertEquals(0, ai.get()); |
| 61 |
> |
LongAccumulator acc = new LongAccumulator(Long::max, 0L); |
| 62 |
> |
acc.accumulate(2); |
| 63 |
> |
assertEquals(2, acc.get()); |
| 64 |
> |
assertEquals(2, acc.getThenReset()); |
| 65 |
> |
assertEquals(0, acc.get()); |
| 66 |
|
} |
| 67 |
|
|
| 68 |
|
/** |
| 69 |
|
* toString returns current value. |
| 70 |
|
*/ |
| 71 |
|
public void testToString() { |
| 72 |
< |
LongAccumulator ai = new LongAccumulator(Long::max, 0L); |
| 73 |
< |
assertEquals("0", ai.toString()); |
| 74 |
< |
ai.accumulate(1); |
| 75 |
< |
assertEquals(Long.toString(1), ai.toString()); |
| 72 |
> |
LongAccumulator acc = new LongAccumulator(Long::max, 0L); |
| 73 |
> |
assertEquals("0", acc.toString()); |
| 74 |
> |
acc.accumulate(1); |
| 75 |
> |
assertEquals(Long.toString(1), acc.toString()); |
| 76 |
|
} |
| 77 |
|
|
| 78 |
|
/** |
| 79 |
|
* intValue returns current value. |
| 80 |
|
*/ |
| 81 |
|
public void testIntValue() { |
| 82 |
< |
LongAccumulator ai = new LongAccumulator(Long::max, 0L); |
| 83 |
< |
assertEquals(0, ai.intValue()); |
| 84 |
< |
ai.accumulate(1); |
| 85 |
< |
assertEquals(1, ai.intValue()); |
| 82 |
> |
LongAccumulator acc = new LongAccumulator(Long::max, 0L); |
| 83 |
> |
assertEquals(0, acc.intValue()); |
| 84 |
> |
acc.accumulate(1); |
| 85 |
> |
assertEquals(1, acc.intValue()); |
| 86 |
|
} |
| 87 |
|
|
| 88 |
|
/** |
| 89 |
|
* longValue returns current value. |
| 90 |
|
*/ |
| 91 |
|
public void testLongValue() { |
| 92 |
< |
LongAccumulator ai = new LongAccumulator(Long::max, 0L); |
| 93 |
< |
assertEquals(0, ai.longValue()); |
| 94 |
< |
ai.accumulate(1); |
| 95 |
< |
assertEquals(1, ai.longValue()); |
| 92 |
> |
LongAccumulator acc = new LongAccumulator(Long::max, 0L); |
| 93 |
> |
assertEquals(0, acc.longValue()); |
| 94 |
> |
acc.accumulate(1); |
| 95 |
> |
assertEquals(1, acc.longValue()); |
| 96 |
|
} |
| 97 |
|
|
| 98 |
|
/** |
| 99 |
|
* floatValue returns current value. |
| 100 |
|
*/ |
| 101 |
|
public void testFloatValue() { |
| 102 |
< |
LongAccumulator ai = new LongAccumulator(Long::max, 0L); |
| 103 |
< |
assertEquals(0.0f, ai.floatValue()); |
| 104 |
< |
ai.accumulate(1); |
| 105 |
< |
assertEquals(1.0f, ai.floatValue()); |
| 102 |
> |
LongAccumulator acc = new LongAccumulator(Long::max, 0L); |
| 103 |
> |
assertEquals(0.0f, acc.floatValue()); |
| 104 |
> |
acc.accumulate(1); |
| 105 |
> |
assertEquals(1.0f, acc.floatValue()); |
| 106 |
|
} |
| 107 |
|
|
| 108 |
|
/** |
| 109 |
|
* doubleValue returns current value. |
| 110 |
|
*/ |
| 111 |
|
public void testDoubleValue() { |
| 112 |
< |
LongAccumulator ai = new LongAccumulator(Long::max, 0L); |
| 113 |
< |
assertEquals(0.0, ai.doubleValue()); |
| 114 |
< |
ai.accumulate(1); |
| 115 |
< |
assertEquals(1.0, ai.doubleValue()); |
| 112 |
> |
LongAccumulator acc = new LongAccumulator(Long::max, 0L); |
| 113 |
> |
assertEquals(0.0, acc.doubleValue()); |
| 114 |
> |
acc.accumulate(1); |
| 115 |
> |
assertEquals(1.0, acc.doubleValue()); |
| 116 |
|
} |
| 117 |
|
|
| 118 |
|
/** |
| 119 |
|
* accumulates by multiple threads produce correct result |
| 120 |
|
*/ |
| 121 |
|
public void testAccumulateAndGetMT() { |
| 122 |
< |
final int incs = 1000000; |
| 123 |
< |
final int nthreads = 4; |
| 124 |
< |
final ExecutorService pool = Executors.newCachedThreadPool(); |
| 125 |
< |
LongAccumulator a = new LongAccumulator(Long::max, 0L); |
| 126 |
< |
Phaser phaser = new Phaser(nthreads + 1); |
| 127 |
< |
for (int i = 0; i < nthreads; ++i) |
| 128 |
< |
pool.execute(new AccumulateerTask(a, phaser, incs)); |
| 123 |
< |
phaser.arriveAndAwaitAdvance(); |
| 124 |
< |
phaser.arriveAndAwaitAdvance(); |
| 125 |
< |
long expected = incs - 1; |
| 126 |
< |
long result = a.get(); |
| 127 |
< |
assertEquals(expected, result); |
| 128 |
< |
pool.shutdown(); |
| 129 |
< |
} |
| 130 |
< |
|
| 131 |
< |
static final class AccumulateerTask implements Runnable { |
| 132 |
< |
final LongAccumulator accumulateer; |
| 133 |
< |
final Phaser phaser; |
| 134 |
< |
final int incs; |
| 135 |
< |
volatile long result; |
| 136 |
< |
AccumulateerTask(LongAccumulator accumulateer, Phaser phaser, int incs) { |
| 137 |
< |
this.accumulateer = accumulateer; |
| 138 |
< |
this.phaser = phaser; |
| 139 |
< |
this.incs = incs; |
| 140 |
< |
} |
| 141 |
< |
|
| 142 |
< |
public void run() { |
| 122 |
> |
final LongAccumulator acc |
| 123 |
> |
= new LongAccumulator((x, y) -> x + y, 0L); |
| 124 |
> |
final int nThreads = ThreadLocalRandom.current().nextInt(1, 5); |
| 125 |
> |
final Phaser phaser = new Phaser(nThreads + 1); |
| 126 |
> |
final int incs = expensiveTests ? 1_000_000 : 100_000; |
| 127 |
> |
final long total = nThreads * incs/2L * (incs - 1); // Gauss |
| 128 |
> |
final Runnable task = () -> { |
| 129 |
|
phaser.arriveAndAwaitAdvance(); |
| 130 |
< |
LongAccumulator a = accumulateer; |
| 131 |
< |
for (int i = 0; i < incs; ++i) |
| 132 |
< |
a.accumulate(i); |
| 133 |
< |
result = a.get(); |
| 130 |
> |
for (int i = 0; i < incs; i++) { |
| 131 |
> |
acc.accumulate((long) i); |
| 132 |
> |
assertTrue(acc.get() <= total); |
| 133 |
> |
} |
| 134 |
|
phaser.arrive(); |
| 135 |
+ |
}; |
| 136 |
+ |
final ExecutorService p = Executors.newCachedThreadPool(); |
| 137 |
+ |
try (PoolCleaner cleaner = cleaner(p)) { |
| 138 |
+ |
for (int i = nThreads; i-->0; ) |
| 139 |
+ |
p.execute(task); |
| 140 |
+ |
phaser.arriveAndAwaitAdvance(); |
| 141 |
+ |
phaser.arriveAndAwaitAdvance(); |
| 142 |
+ |
assertEquals(total, acc.get()); |
| 143 |
|
} |
| 144 |
|
} |
| 145 |
|
|
