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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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*/ |
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|
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import junit.framework.*; |
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import java.util.concurrent.*; |
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import java.util.concurrent.atomic.LongAdder; |
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|
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public class LongAdderTest extends JSR166TestCase { |
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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(LongAdderTest.class); |
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} |
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|
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/** |
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* default constructed initializes to zero |
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*/ |
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public void testConstructor() { |
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LongAdder ai = new LongAdder(); |
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assertEquals(0, ai.sum()); |
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} |
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|
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/** |
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* add adds given value to current, and sum returns current value |
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*/ |
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public void testAddAndSum() { |
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LongAdder ai = new LongAdder(); |
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ai.add(2); |
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assertEquals(2, ai.sum()); |
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ai.add(-4); |
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assertEquals(-2, ai.sum()); |
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} |
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|
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/** |
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* decrement decrements and sum returns current value |
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*/ |
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public void testDecrementAndsum() { |
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LongAdder ai = new LongAdder(); |
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ai.decrement(); |
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assertEquals(-1, ai.sum()); |
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ai.decrement(); |
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assertEquals(-2, ai.sum()); |
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} |
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|
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/** |
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* incrementAndGet increments and returns current value |
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*/ |
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public void testIncrementAndsum() { |
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LongAdder ai = new LongAdder(); |
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ai.increment(); |
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assertEquals(1, ai.sum()); |
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ai.increment(); |
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assertEquals(2, ai.sum()); |
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} |
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|
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/** |
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* reset zeroes sum |
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*/ |
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public void testReset() { |
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LongAdder ai = new LongAdder(); |
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ai.add(2); |
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assertEquals(2, ai.sum()); |
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ai.reset(); |
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assertEquals(0, ai.sum()); |
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} |
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|
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/** |
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* sumThenReset returns sum then zeros |
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*/ |
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public void testSumThenReset() { |
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LongAdder ai = new LongAdder(); |
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ai.add(2); |
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assertEquals(2, ai.sum()); |
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assertEquals(2, ai.sumThenReset()); |
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assertEquals(0, ai.sum()); |
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} |
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|
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/** |
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* a deserialized serialized adder holds same value |
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*/ |
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public void testSerialization() throws Exception { |
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LongAdder x = new LongAdder(); |
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LongAdder y = serialClone(x); |
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assertNotSame(x, y); |
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x.add(-22); |
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LongAdder z = serialClone(x); |
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assertNotSame(y, z); |
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assertEquals(-22, x.sum()); |
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assertEquals(0, y.sum()); |
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assertEquals(-22, z.sum()); |
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} |
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|
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/** |
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* toString returns current value. |
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*/ |
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public void testToString() { |
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LongAdder ai = new LongAdder(); |
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assertEquals("0", ai.toString()); |
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ai.increment(); |
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assertEquals(Long.toString(1), ai.toString()); |
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} |
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|
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/** |
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* intValue returns current value. |
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*/ |
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public void testIntValue() { |
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LongAdder ai = new LongAdder(); |
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assertEquals(0, ai.intValue()); |
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ai.increment(); |
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assertEquals(1, ai.intValue()); |
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} |
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|
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/** |
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* longValue returns current value. |
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*/ |
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public void testLongValue() { |
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LongAdder ai = new LongAdder(); |
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assertEquals(0, ai.longValue()); |
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ai.increment(); |
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assertEquals(1, ai.longValue()); |
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} |
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|
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/** |
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* floatValue returns current value. |
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*/ |
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public void testFloatValue() { |
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LongAdder ai = new LongAdder(); |
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assertEquals(0.0f, ai.floatValue()); |
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ai.increment(); |
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assertEquals(1.0f, ai.floatValue()); |
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} |
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|
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/** |
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* doubleValue returns current value. |
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*/ |
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public void testDoubleValue() { |
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LongAdder ai = new LongAdder(); |
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assertEquals(0.0, ai.doubleValue()); |
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ai.increment(); |
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assertEquals(1.0, ai.doubleValue()); |
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} |
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|
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/** |
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* adds by multiple threads produce correct sum |
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*/ |
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public void testAddAndSumMT() { |
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final int incs = 1000000; |
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final int nthreads = 4; |
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final ExecutorService pool = Executors.newCachedThreadPool(); |
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LongAdder a = new LongAdder(); |
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Phaser phaser = new Phaser(nthreads + 1); |
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for (int i = 0; i < nthreads; ++i) |
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pool.execute(new AdderTask(a, phaser, incs)); |
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phaser.arriveAndAwaitAdvance(); |
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phaser.arriveAndAwaitAdvance(); |
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long total = (long)nthreads * incs; |
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long sum = a.sum(); |
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assertEquals(sum, total); |
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pool.shutdown(); |
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} |
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|
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static final class AdderTask implements Runnable { |
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final LongAdder adder; |
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final Phaser phaser; |
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final int incs; |
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volatile long result; |
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AdderTask(LongAdder adder, Phaser phaser, int incs) { |
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this.adder = adder; |
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this.phaser = phaser; |
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this.incs = incs; |
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} |
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|
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public void run() { |
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phaser.arriveAndAwaitAdvance(); |
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LongAdder a = adder; |
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for (int i = 0; i < incs; ++i) |
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a.add(1L); |
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result = a.sum(); |
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phaser.arrive(); |
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} |
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} |
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|
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} |
