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/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* 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 java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.List;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorCompletionService;
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(cs::submit);
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);
}
ArrayList<Integer> results;
void use(Integer x) {
if (results == null) results = new ArrayList<Integer>();
results.add(x);
}
/**
* The first "solvers" sample code in the class javadoc works.
*/
public void testSolveAll()
throws InterruptedException, ExecutionException {
results = null;
Set<Callable<Integer>> solvers = Set.of(
() -> null,
() -> 1,
() -> 2,
() -> 3,
() -> null);
solveAll(cachedThreadPool, solvers);
results.sort(Comparator.naturalOrder());
assertEquals(List.of(1, 2, 3), results);
}
/**
* The second "solvers" sample code in the class javadoc works.
*/
public void testSolveAny()
throws InterruptedException {
results = null;
Set<Callable<Integer>> solvers = Set.of(
() -> { throw new ArithmeticException(); },
() -> null,
() -> 1,
() -> 2);
solveAny(cachedThreadPool, solvers);
assertEquals(1, results.size());
Integer elt = results.get(0);
assertTrue(elt.equals(1) || elt.equals(2));
}
}
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