ExecutorTest.java

/*
 * Copyright 2010-2017 Norwegian Agency for Public Management and eGovernment (Difi)
 *
 * Licensed under the EUPL, Version 1.1 or – as soon they
 * will be approved by the European Commission - subsequent
 * versions of the EUPL (the "Licence");
 *
 * You may not use this work except in compliance with the Licence.
 *
 * You may obtain a copy of the Licence at:
 *
 * https://joinup.ec.europa.eu/community/eupl/og_page/eupl
 *
 * Unless required by applicable law or agreed to in
 * writing, software distributed under the Licence is
 * distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied.
 * See the Licence for the specific language governing
 * permissions and limitations under the Licence.
 */

package eu.sendregning.oxalis;

import org.testng.annotations.Test;

import java.util.concurrent.*;

import static org.testng.Assert.assertEquals;

/**
 * @author steinar
 *         Date: 09.01.2017
 *         Time: 15.40
 */
public class ExecutorTest {

    @Test
    public void executeSeveralTasksSomeOfWhichFails() throws Exception {

        ExecutorService executorService = Executors.newFixedThreadPool(2);
        ExecutorCompletionService<TestResult> ecs = new ExecutorCompletionService<>(executorService);

        for (int i = 0; i < 50; i++) {

            final int n = i;

            Future<TestResult> future = ecs.submit(new Callable<TestResult>() {

                @Override
                public TestResult call() throws Exception {
                    System.out.println(Thread.currentThread().getName() + " executing no #" + n);
                    if (n > 0 && n % 10 == 0) {
                        throw new Exception("Odd things happening for no #" + n);
                    }
                    return new TestResult(n);
                }
            });
        }


        int executedTaskCount = 0;
        int failed = 0;
        for (int i = 0; i < 50; i++, executedTaskCount++) {
            try {
                Future<TestResult> future = ecs.take();
                TestResult tr = future.get();
                System.out.println(tr.getId() + " executedTaskCount");
            } catch (InterruptedException e) {
                System.err.println(e.getMessage());
            } catch (ExecutionException e) {
                // Figure out which task failed
                System.out.println("Execution failed: " + e.getMessage());
                failed++;
            }
        }
        assertEquals(executedTaskCount, 50);
        assertEquals(failed, 4);
    }

    static class TestResult {
        private final int id;

        public TestResult(int id) {
            this.id = id;
        }

        public int getId() {
            return id;
        }
    }
}