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.LongAdder; |
| 13 | |
| 14 | import junit.framework.Test; |
| 15 | import junit.framework.TestSuite; |
| 16 | |
| 17 | public class LongAdderTest 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(LongAdderTest.class); |
| 26 | // } |
| 27 | |
| 28 | /** |
| 29 | * default constructed initializes to zero |
| 30 | */ |
| 31 | public void testConstructor() { |
| 32 | LongAdder ai = new LongAdder(); |
| 33 | assertEquals(0, ai.sum()); |
| 34 | } |
| 35 | |
| 36 | /** |
| 37 | * add adds given value to current, and sum returns current value |
| 38 | */ |
| 39 | public void testAddAndSum() { |
| 40 | LongAdder ai = new LongAdder(); |
| 41 | ai.add(2); |
| 42 | assertEquals(2, ai.sum()); |
| 43 | ai.add(-4); |
| 44 | assertEquals(-2, ai.sum()); |
| 45 | } |
| 46 | |
| 47 | /** |
| 48 | * decrement decrements and sum returns current value |
| 49 | */ |
| 50 | public void testDecrementAndsum() { |
| 51 | LongAdder ai = new LongAdder(); |
| 52 | ai.decrement(); |
| 53 | assertEquals(-1, ai.sum()); |
| 54 | ai.decrement(); |
| 55 | assertEquals(-2, ai.sum()); |
| 56 | } |
| 57 | |
| 58 | /** |
| 59 | * incrementAndGet increments and returns current value |
| 60 | */ |
| 61 | public void testIncrementAndsum() { |
| 62 | LongAdder ai = new LongAdder(); |
| 63 | ai.increment(); |
| 64 | assertEquals(1, ai.sum()); |
| 65 | ai.increment(); |
| 66 | assertEquals(2, ai.sum()); |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * reset() causes subsequent sum() to return zero |
| 71 | */ |
| 72 | public void testReset() { |
| 73 | LongAdder ai = new LongAdder(); |
| 74 | ai.add(2); |
| 75 | assertEquals(2, ai.sum()); |
| 76 | ai.reset(); |
| 77 | assertEquals(0, ai.sum()); |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * sumThenReset() returns sum; subsequent sum() returns zero |
| 82 | */ |
| 83 | public void testSumThenReset() { |
| 84 | LongAdder ai = new LongAdder(); |
| 85 | ai.add(2); |
| 86 | assertEquals(2, ai.sum()); |
| 87 | assertEquals(2, ai.sumThenReset()); |
| 88 | assertEquals(0, ai.sum()); |
| 89 | } |
| 90 | |
| 91 | /** |
| 92 | * a deserialized serialized adder holds same value |
| 93 | */ |
| 94 | public void testSerialization() throws Exception { |
| 95 | LongAdder x = new LongAdder(); |
| 96 | LongAdder y = serialClone(x); |
| 97 | assertNotSame(x, y); |
| 98 | x.add(-22); |
| 99 | LongAdder z = serialClone(x); |
| 100 | assertNotSame(y, z); |
| 101 | assertEquals(-22, x.sum()); |
| 102 | assertEquals(0, y.sum()); |
| 103 | assertEquals(-22, z.sum()); |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * toString returns current value. |
| 108 | */ |
| 109 | public void testToString() { |
| 110 | LongAdder ai = new LongAdder(); |
| 111 | assertEquals("0", ai.toString()); |
| 112 | ai.increment(); |
| 113 | assertEquals(Long.toString(1), ai.toString()); |
| 114 | } |
| 115 | |
| 116 | /** |
| 117 | * intValue returns current value. |
| 118 | */ |
| 119 | public void testIntValue() { |
| 120 | LongAdder ai = new LongAdder(); |
| 121 | assertEquals(0, ai.intValue()); |
| 122 | ai.increment(); |
| 123 | assertEquals(1, ai.intValue()); |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * longValue returns current value. |
| 128 | */ |
| 129 | public void testLongValue() { |
| 130 | LongAdder ai = new LongAdder(); |
| 131 | assertEquals(0, ai.longValue()); |
| 132 | ai.increment(); |
| 133 | assertEquals(1, ai.longValue()); |
| 134 | } |
| 135 | |
| 136 | /** |
| 137 | * floatValue returns current value. |
| 138 | */ |
| 139 | public void testFloatValue() { |
| 140 | LongAdder ai = new LongAdder(); |
| 141 | assertEquals(0.0f, ai.floatValue()); |
| 142 | ai.increment(); |
| 143 | assertEquals(1.0f, ai.floatValue()); |
| 144 | } |
| 145 | |
| 146 | /** |
| 147 | * doubleValue returns current value. |
| 148 | */ |
| 149 | public void testDoubleValue() { |
| 150 | LongAdder ai = new LongAdder(); |
| 151 | assertEquals(0.0, ai.doubleValue()); |
| 152 | ai.increment(); |
| 153 | assertEquals(1.0, ai.doubleValue()); |
| 154 | } |
| 155 | |
| 156 | /** |
| 157 | * adds by multiple threads produce correct sum |
| 158 | */ |
| 159 | public void testAddAndSumMT() throws Throwable { |
| 160 | final int incs = 1000000; |
| 161 | final int nthreads = 4; |
| 162 | final ExecutorService pool = Executors.newCachedThreadPool(); |
| 163 | LongAdder a = new LongAdder(); |
| 164 | CyclicBarrier barrier = new CyclicBarrier(nthreads + 1); |
| 165 | for (int i = 0; i < nthreads; ++i) |
| 166 | pool.execute(new AdderTask(a, barrier, incs)); |
| 167 | barrier.await(); |
| 168 | barrier.await(); |
| 169 | long total = (long)nthreads * incs; |
| 170 | long sum = a.sum(); |
| 171 | assertEquals(sum, total); |
| 172 | pool.shutdown(); |
| 173 | } |
| 174 | |
| 175 | static final class AdderTask implements Runnable { |
| 176 | final LongAdder adder; |
| 177 | final CyclicBarrier barrier; |
| 178 | final int incs; |
| 179 | volatile long result; |
| 180 | AdderTask(LongAdder adder, CyclicBarrier barrier, int incs) { |
| 181 | this.adder = adder; |
| 182 | this.barrier = barrier; |
| 183 | this.incs = incs; |
| 184 | } |
| 185 | |
| 186 | public void run() { |
| 187 | try { |
| 188 | barrier.await(); |
| 189 | LongAdder a = adder; |
| 190 | for (int i = 0; i < incs; ++i) |
| 191 | a.add(1L); |
| 192 | result = a.sum(); |
| 193 | barrier.await(); |
| 194 | } catch (Throwable t) { throw new Error(t); } |
| 195 | } |
| 196 | } |
| 197 | |
| 198 | } |