test/tck/ExecutorCompletionService9Test.java

/*
 * Written by Doug Lea and Martin Buchholz 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 static java.util.concurrent.TimeUnit.MILLISECONDS;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Set;
import java.util.HashSet;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.Future;

import junit.framework.Test;
import junit.framework.TestSuite;

public class ExecutorCompletionService9Test extends JSR166TestCase {
    public static void main(String[] args) {
        main(suite(), args);
    }
    public static Test suite() {
        return new TestSuite(ExecutorCompletionService9Test.class);
    }

    void solveAll(Executor e,
                  Collection<Callable<Integer>> solvers)
        throws InterruptedException, ExecutionException {
        CompletionService<Integer> cs
            = new ExecutorCompletionService<>(e);
        solvers.forEach((solver) -> cs.submit(solver));
        for (int i = solvers.size(); i > 0; i--) {
            Integer r = cs.take().get();
            if (r != null)
                use(r);
        }
    }

    void solveAny(Executor e,
                  Collection<Callable<Integer>> solvers)
        throws InterruptedException {
        CompletionService<Integer> cs
            = new ExecutorCompletionService<>(e);
        int n = solvers.size();
        List<Future<Integer>> futures = new ArrayList<>(n);
        Integer result = null;
        try {
            solvers.forEach((solver) -> futures.add(cs.submit(solver)));
            for (int i = n; i > 0; i--) {
                try {
                    Integer r = cs.take().get();
                    if (r != null) {
                        result = r;
                        break;
                    }
                } catch (ExecutionException ignore) {}
            }
        } finally {
            futures.forEach((future) -> future.cancel(true));
        }

        if (result != null)
            use(result);
    }

    HashSet<Integer> results;

    void use(Integer x) {
        if (results == null) results = new HashSet<Integer>();
        results.add(x);
    }

    /**
     * The first "solvers" sample code in the class javadoc works.
     */
    public void testSolveAll()
        throws InterruptedException, ExecutionException {
        Set<Callable<Integer>> solvers = Set.of(
            () -> null,
            () -> 1,
            () -> 2,
            () -> 3,
            () -> null);
        solveAll(ForkJoinPool.commonPool(), solvers);
        assertEquals(Set.of(1, 2, 3), results);
    }
    
    /**
     * The second "solvers" sample code in the class javadoc works.
     */
    public void testSolveAny()
        throws InterruptedException {
        Set<Callable<Integer>> solvers = Set.of(
            () -> { throw new ArithmeticException(); },
            () -> null,
            () -> 1,
            () -> 2);
        solveAny(ForkJoinPool.commonPool(), solvers);
        assertEquals(1, results.size());
        Integer elt = results.iterator().next();
        assertTrue(elt.equals(1) || elt.equals(2));
    }

}
Revision:	1.1
Committed:	Sun May 22 01:09:21 2016 UTC (7 years, 11 months ago) by jsr166
Branch:	MAIN
Log Message:	improve and test ExecutorCompletionService sample code
#	User	Rev	Content
1	jsr166	1.1	/*
2			* Written by Doug Lea and Martin Buchholz with assistance from
3			* members of JCP JSR-166 Expert Group and released to the public
4			* domain, as explained at
5			* http://creativecommons.org/publicdomain/zero/1.0/
6			*/
7
8			import static java.util.concurrent.TimeUnit.MILLISECONDS;
9
10			import java.util.ArrayList;
11			import java.util.Collection;
12			import java.util.List;
13			import java.util.Set;
14			import java.util.HashSet;
15			import java.util.concurrent.Callable;
16			import java.util.concurrent.CompletionService;
17			import java.util.concurrent.ExecutionException;
18			import java.util.concurrent.ExecutorCompletionService;
19			import java.util.concurrent.Executor;
20			import java.util.concurrent.ExecutorService;
21			import java.util.concurrent.ForkJoinPool;
22			import java.util.concurrent.Future;
23
24			import junit.framework.Test;
25			import junit.framework.TestSuite;
26
27			public class ExecutorCompletionService9Test extends JSR166TestCase {
28			public static void main(String[] args) {
29			main(suite(), args);
30			}
31			public static Test suite() {
32			return new TestSuite(ExecutorCompletionService9Test.class);
33			}
34
35			void solveAll(Executor e,
36			Collection<Callable<Integer>> solvers)
37			throws InterruptedException, ExecutionException {
38			CompletionService<Integer> cs
39			= new ExecutorCompletionService<>(e);
40			solvers.forEach((solver) -> cs.submit(solver));
41			for (int i = solvers.size(); i > 0; i--) {
42			Integer r = cs.take().get();
43			if (r != null)
44			use(r);
45			}
46			}
47
48			void solveAny(Executor e,
49			Collection<Callable<Integer>> solvers)
50			throws InterruptedException {
51			CompletionService<Integer> cs
52			= new ExecutorCompletionService<>(e);
53			int n = solvers.size();
54			List<Future<Integer>> futures = new ArrayList<>(n);
55			Integer result = null;
56			try {
57			solvers.forEach((solver) -> futures.add(cs.submit(solver)));
58			for (int i = n; i > 0; i--) {
59			try {
60			Integer r = cs.take().get();
61			if (r != null) {
62			result = r;
63			break;
64			}
65			} catch (ExecutionException ignore) {}
66			}
67			} finally {
68			futures.forEach((future) -> future.cancel(true));
69			}
70
71			if (result != null)
72			use(result);
73			}
74
75			HashSet<Integer> results;
76
77			void use(Integer x) {
78			if (results == null) results = new HashSet<Integer>();
79			results.add(x);
80			}
81
82			/**
83			* The first "solvers" sample code in the class javadoc works.
84			*/
85			public void testSolveAll()
86			throws InterruptedException, ExecutionException {
87			Set<Callable<Integer>> solvers = Set.of(
88			() -> null,
89			() -> 1,
90			() -> 2,
91			() -> 3,
92			() -> null);
93			solveAll(ForkJoinPool.commonPool(), solvers);
94			assertEquals(Set.of(1, 2, 3), results);
95			}
96
97			/**
98			* The second "solvers" sample code in the class javadoc works.
99			*/
100			public void testSolveAny()
101			throws InterruptedException {
102			Set<Callable<Integer>> solvers = Set.of(
103			() -> { throw new ArithmeticException(); },
104			() -> null,
105			() -> 1,
106			() -> 2);
107			solveAny(ForkJoinPool.commonPool(), solvers);
108			assertEquals(1, results.size());
109			Integer elt = results.iterator().next();
110			assertTrue(elt.equals(1) \|\| elt.equals(2));
111			}
112
113			}