Przemyslaw Szczepaniak | b8b7511 | 2016-03-11 15:59:10 +0000 | [diff] [blame] | 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 | package jsr166; |
| 8 | |
| 9 | import java.util.concurrent.CyclicBarrier; |
| 10 | import java.util.concurrent.Executors; |
| 11 | import java.util.concurrent.ExecutorService; |
| 12 | import java.util.concurrent.atomic.DoubleAdder; |
| 13 | |
| 14 | import junit.framework.Test; |
| 15 | import junit.framework.TestSuite; |
| 16 | |
| 17 | public class DoubleAdderTest extends JSR166TestCase { |
| 18 | // android-note: Removed because the CTS runner does a bad job of |
| 19 | // retrying tests that have suite() declarations. |
| 20 | // |
| 21 | // public static void main(String[] args) { |
| 22 | // main(suite(), args); |
| 23 | // } |
| 24 | // public static Test suite() { |
| 25 | // return new TestSuite(DoubleAdderTest.class); |
| 26 | // } |
| 27 | |
| 28 | /** |
| 29 | * default constructed initializes to zero |
| 30 | */ |
| 31 | public void testConstructor() { |
| 32 | DoubleAdder ai = new DoubleAdder(); |
| 33 | assertEquals(0.0, ai.sum()); |
| 34 | } |
| 35 | |
| 36 | /** |
| 37 | * add adds given value to current, and sum returns current value |
| 38 | */ |
| 39 | public void testAddAndSum() { |
| 40 | DoubleAdder ai = new DoubleAdder(); |
| 41 | ai.add(2.0); |
| 42 | assertEquals(2.0, ai.sum()); |
| 43 | ai.add(-4.0); |
| 44 | assertEquals(-2.0, ai.sum()); |
| 45 | } |
| 46 | |
| 47 | /** |
| 48 | * reset() causes subsequent sum() to return zero |
| 49 | */ |
| 50 | public void testReset() { |
| 51 | DoubleAdder ai = new DoubleAdder(); |
| 52 | ai.add(2.0); |
| 53 | assertEquals(2.0, ai.sum()); |
| 54 | ai.reset(); |
| 55 | assertEquals(0.0, ai.sum()); |
| 56 | } |
| 57 | |
| 58 | /** |
| 59 | * sumThenReset() returns sum; subsequent sum() returns zero |
| 60 | */ |
| 61 | public void testSumThenReset() { |
| 62 | DoubleAdder ai = new DoubleAdder(); |
| 63 | ai.add(2.0); |
| 64 | assertEquals(2.0, ai.sum()); |
| 65 | assertEquals(2.0, ai.sumThenReset()); |
| 66 | assertEquals(0.0, ai.sum()); |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * a deserialized serialized adder holds same value |
| 71 | */ |
| 72 | public void testSerialization() throws Exception { |
| 73 | DoubleAdder x = new DoubleAdder(); |
| 74 | DoubleAdder y = serialClone(x); |
| 75 | assertNotSame(x, y); |
| 76 | x.add(-22.0); |
| 77 | DoubleAdder z = serialClone(x); |
| 78 | assertEquals(-22.0, x.sum()); |
| 79 | assertEquals(0.0, y.sum()); |
| 80 | assertEquals(-22.0, z.sum()); |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * toString returns current value. |
| 85 | */ |
| 86 | public void testToString() { |
| 87 | DoubleAdder ai = new DoubleAdder(); |
| 88 | assertEquals(Double.toString(0.0), ai.toString()); |
| 89 | ai.add(1.0); |
| 90 | assertEquals(Double.toString(1.0), ai.toString()); |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * intValue returns current value. |
| 95 | */ |
| 96 | public void testIntValue() { |
| 97 | DoubleAdder ai = new DoubleAdder(); |
| 98 | assertEquals(0, ai.intValue()); |
| 99 | ai.add(1.0); |
| 100 | assertEquals(1, ai.intValue()); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * longValue returns current value. |
| 105 | */ |
| 106 | public void testLongValue() { |
| 107 | DoubleAdder ai = new DoubleAdder(); |
| 108 | assertEquals(0, ai.longValue()); |
| 109 | ai.add(1.0); |
| 110 | assertEquals(1, ai.longValue()); |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * floatValue returns current value. |
| 115 | */ |
| 116 | public void testFloatValue() { |
| 117 | DoubleAdder ai = new DoubleAdder(); |
| 118 | assertEquals(0.0f, ai.floatValue()); |
| 119 | ai.add(1.0); |
| 120 | assertEquals(1.0f, ai.floatValue()); |
| 121 | } |
| 122 | |
| 123 | /** |
| 124 | * doubleValue returns current value. |
| 125 | */ |
| 126 | public void testDoubleValue() { |
| 127 | DoubleAdder ai = new DoubleAdder(); |
| 128 | assertEquals(0.0, ai.doubleValue()); |
| 129 | ai.add(1.0); |
| 130 | assertEquals(1.0, ai.doubleValue()); |
| 131 | } |
| 132 | |
| 133 | /** |
| 134 | * adds by multiple threads produce correct sum |
| 135 | */ |
| 136 | public void testAddAndSumMT() throws Throwable { |
| 137 | final int incs = 1000000; |
| 138 | final int nthreads = 4; |
| 139 | final ExecutorService pool = Executors.newCachedThreadPool(); |
| 140 | DoubleAdder a = new DoubleAdder(); |
| 141 | CyclicBarrier barrier = new CyclicBarrier(nthreads + 1); |
| 142 | for (int i = 0; i < nthreads; ++i) |
| 143 | pool.execute(new AdderTask(a, barrier, incs)); |
| 144 | barrier.await(); |
| 145 | barrier.await(); |
| 146 | double total = (long)nthreads * incs; |
| 147 | double sum = a.sum(); |
| 148 | assertEquals(sum, total); |
| 149 | pool.shutdown(); |
| 150 | } |
| 151 | |
| 152 | static final class AdderTask implements Runnable { |
| 153 | final DoubleAdder adder; |
| 154 | final CyclicBarrier barrier; |
| 155 | final int incs; |
| 156 | volatile double result; |
| 157 | AdderTask(DoubleAdder adder, CyclicBarrier barrier, int incs) { |
| 158 | this.adder = adder; |
| 159 | this.barrier = barrier; |
| 160 | this.incs = incs; |
| 161 | } |
| 162 | |
| 163 | public void run() { |
| 164 | try { |
| 165 | barrier.await(); |
| 166 | DoubleAdder a = adder; |
| 167 | for (int i = 0; i < incs; ++i) |
| 168 | a.add(1.0); |
| 169 | result = a.sum(); |
| 170 | barrier.await(); |
| 171 | } catch (Throwable t) { throw new Error(t); } |
| 172 | } |
| 173 | } |
| 174 | |
| 175 | } |