test/tck/LongAccumulatorTest.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

import junit.framework.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.LongAccumulator;

public class LongAccumulatorTest extends JSR166TestCase {
    public static void main(String[] args) {
        junit.textui.TestRunner.run(suite());
    }
    public static Test suite() {
        return new TestSuite(LongAccumulatorTest.class);
    }

    /**
     * default constructed initializes to zero
     */
    public void testConstructor() {
        LongAccumulator ai = new LongAccumulator(Long::max, 0L);
        assertEquals(0, ai.get());
    }

    /**
     * accumulate accumulates given value to current, and get returns current value
     */
    public void testAccumulateAndGet() {
        LongAccumulator ai = new LongAccumulator(Long::max, 0L);
        ai.accumulate(2);
        assertEquals(2, ai.get());
        ai.accumulate(-4);
        assertEquals(2, ai.get());
        ai.accumulate(4);
        assertEquals(4, ai.get());
    }

    /**
     * reset zeroes get
     */
    public void testReset() {
        LongAccumulator ai = new LongAccumulator(Long::max, 0L);
        ai.accumulate(2);
        assertEquals(2, ai.get());
        ai.reset();
        assertEquals(0, ai.get());
    }

    /**
     * getThenReset returns get then zeros
     */
    public void testGetThenReset() {
        LongAccumulator ai = new LongAccumulator(Long::max, 0L);
        ai.accumulate(2);
        assertEquals(2, ai.get());
        assertEquals(2, ai.getThenReset());
        assertEquals(0, ai.get());
    }

    /**
     * toString returns current value.
     */
    public void testToString() {
        LongAccumulator ai = new LongAccumulator(Long::max, 0L);
        assertEquals("0", ai.toString());
        ai.accumulate(1);
        assertEquals(Long.toString(1), ai.toString());
    }

    /**
     * intValue returns current value.
     */
    public void testIntValue() {
        LongAccumulator ai = new LongAccumulator(Long::max, 0L);
        assertEquals(0, ai.intValue());
        ai.accumulate(1);
        assertEquals(1, ai.intValue());
    }

    /**
     * longValue returns current value.
     */
    public void testLongValue() {
        LongAccumulator ai = new LongAccumulator(Long::max, 0L);
        assertEquals(0, ai.longValue());
        ai.accumulate(1);
        assertEquals(1, ai.longValue());
    }

    /**
     * floatValue returns current value.
     */
    public void testFloatValue() {
        LongAccumulator ai = new LongAccumulator(Long::max, 0L);
        assertEquals(0.0f, ai.floatValue());
        ai.accumulate(1);
        assertEquals(1.0f, ai.floatValue());
    }

    /**
     * doubleValue returns current value.
     */
    public void testDoubleValue() {
        LongAccumulator ai = new LongAccumulator(Long::max, 0L);
        assertEquals(0.0, ai.doubleValue());
        ai.accumulate(1);
        assertEquals(1.0, ai.doubleValue());
    }

    /**
     * accumulates by multiple threads produce correct result
     */
    public void testAccumulateAndGetMT() {
        final int incs = 1000000;
        final int nthreads = 4;
        final ExecutorService pool = Executors.newCachedThreadPool();
        LongAccumulator a = new LongAccumulator(Long::max, 0L);
        Phaser phaser = new Phaser(nthreads + 1);
        for (int i = 0; i < nthreads; ++i)
            pool.execute(new AccumulateerTask(a, phaser, incs));
        phaser.arriveAndAwaitAdvance();
        phaser.arriveAndAwaitAdvance();
        long expected = incs - 1;
        long result = a.get();
        assertEquals(expected, result);
        pool.shutdown();
    }

   static final class AccumulateerTask implements Runnable {
        final LongAccumulator accumulateer;
        final Phaser phaser;
        final int incs;
        volatile long result;
        AccumulateerTask(LongAccumulator accumulateer, Phaser phaser, int incs) { 
            this.accumulateer = accumulateer; 
            this.phaser = phaser;
            this.incs = incs;
        }

        public void run() {
            phaser.arriveAndAwaitAdvance();
            LongAccumulator a = accumulateer;
            for (int i = 0; i < incs; ++i)
                a.accumulate(i);
            result = a.get();
            phaser.arrive();
        }
    }

}
Revision:	1.1
Committed:	Wed Mar 20 20:29:02 2013 UTC (11 years, 1 month ago) by dl
Branch:	MAIN
Log Message:	Basic coverage for LongAdder and friends
#	Content
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 junit.framework.*;
8	import java.util.concurrent.*;
9	import java.util.concurrent.atomic.LongAccumulator;
10
11	public class LongAccumulatorTest extends JSR166TestCase {
12	public static void main(String[] args) {
13	junit.textui.TestRunner.run(suite());
14	}
15	public static Test suite() {
16	return new TestSuite(LongAccumulatorTest.class);
17	}
18
19	/**
20	* default constructed initializes to zero
21	*/
22	public void testConstructor() {
23	LongAccumulator ai = new LongAccumulator(Long::max, 0L);
24	assertEquals(0, ai.get());
25	}
26
27	/**
28	* accumulate accumulates given value to current, and get returns current value
29	*/
30	public void testAccumulateAndGet() {
31	LongAccumulator ai = new LongAccumulator(Long::max, 0L);
32	ai.accumulate(2);
33	assertEquals(2, ai.get());
34	ai.accumulate(-4);
35	assertEquals(2, ai.get());
36	ai.accumulate(4);
37	assertEquals(4, ai.get());
38	}
39
40	/**
41	* reset zeroes get
42	*/
43	public void testReset() {
44	LongAccumulator ai = new LongAccumulator(Long::max, 0L);
45	ai.accumulate(2);
46	assertEquals(2, ai.get());
47	ai.reset();
48	assertEquals(0, ai.get());
49	}
50
51	/**
52	* getThenReset returns get then zeros
53	*/
54	public void testGetThenReset() {
55	LongAccumulator ai = new LongAccumulator(Long::max, 0L);
56	ai.accumulate(2);
57	assertEquals(2, ai.get());
58	assertEquals(2, ai.getThenReset());
59	assertEquals(0, ai.get());
60	}
61
62	/**
63	* toString returns current value.
64	*/
65	public void testToString() {
66	LongAccumulator ai = new LongAccumulator(Long::max, 0L);
67	assertEquals("0", ai.toString());
68	ai.accumulate(1);
69	assertEquals(Long.toString(1), ai.toString());
70	}
71
72	/**
73	* intValue returns current value.
74	*/
75	public void testIntValue() {
76	LongAccumulator ai = new LongAccumulator(Long::max, 0L);
77	assertEquals(0, ai.intValue());
78	ai.accumulate(1);
79	assertEquals(1, ai.intValue());
80	}
81
82	/**
83	* longValue returns current value.
84	*/
85	public void testLongValue() {
86	LongAccumulator ai = new LongAccumulator(Long::max, 0L);
87	assertEquals(0, ai.longValue());
88	ai.accumulate(1);
89	assertEquals(1, ai.longValue());
90	}
91
92	/**
93	* floatValue returns current value.
94	*/
95	public void testFloatValue() {
96	LongAccumulator ai = new LongAccumulator(Long::max, 0L);
97	assertEquals(0.0f, ai.floatValue());
98	ai.accumulate(1);
99	assertEquals(1.0f, ai.floatValue());
100	}
101
102	/**
103	* doubleValue returns current value.
104	*/
105	public void testDoubleValue() {
106	LongAccumulator ai = new LongAccumulator(Long::max, 0L);
107	assertEquals(0.0, ai.doubleValue());
108	ai.accumulate(1);
109	assertEquals(1.0, ai.doubleValue());
110	}
111
112	/**
113	* accumulates by multiple threads produce correct result
114	*/
115	public void testAccumulateAndGetMT() {
116	final int incs = 1000000;
117	final int nthreads = 4;
118	final ExecutorService pool = Executors.newCachedThreadPool();
119	LongAccumulator a = new LongAccumulator(Long::max, 0L);
120	Phaser phaser = new Phaser(nthreads + 1);
121	for (int i = 0; i < nthreads; ++i)
122	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() {
143	phaser.arriveAndAwaitAdvance();
144	LongAccumulator a = accumulateer;
145	for (int i = 0; i < incs; ++i)
146	a.accumulate(i);
147	result = a.get();
148	phaser.arrive();
149	}
150	}
151
152	}