/*

 * Copyright (c) 2006, 2012, Oracle and/or its affiliates. All rights reserved.

 * 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.

 */

/*

 * @test

 * @bug 6431315

 * @summary ExecutorService.invokeAll might hang

 * @author Martin Buchholz

 */

import java.util.ArrayList;

import java.util.Collection;

import java.util.concurrent.Callable;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.RejectedExecutionException;

import java.util.concurrent.TimeUnit;

/**

 * Adapted from Doug Lea, which was...

 * adapted from a posting by Tom Sugden tom at epcc.ed.ac.uk

 */

public class BlockingTaskExecutor {

    static void realMain(String[] args) throws Throwable {

        for (int i = 1; i <= 100; i++) {

            System.out.print(".");

            test();

        }

    }

    static void test() throws Throwable {

        final ExecutorService executor = Executors.newCachedThreadPool();

        final NotificationReceiver notifiee1 = new NotificationReceiver();

        final NotificationReceiver notifiee2 = new NotificationReceiver();

        final Collection<Callable<Object>> tasks = new ArrayList<>();

        tasks.add(new BlockingTask(notifiee1));

        tasks.add(new BlockingTask(notifiee2));

        tasks.add(new NonBlockingTask());

        // start a thread to invoke the tasks

        Thread thread = new Thread() { public void run() {

            try { executor.invokeAll(tasks); }

            catch (RejectedExecutionException t) {/* OK */}

            catch (Throwable t) { unexpected(t); }}};

        thread.start();

        // Wait until tasks begin execution

        notifiee1.waitForNotification();

        notifiee2.waitForNotification();

        // Now try to shutdown the executor service while tasks

        // are blocked.  This should cause the tasks to be

        // interrupted.

        executor.shutdownNow();

        if (! executor.awaitTermination(5L, TimeUnit.SECONDS))

            throw new Error("Executor stuck");

        // Wait for the invocation thread to complete.

        thread.join(5000);

        if (thread.isAlive()) {

            thread.interrupt();

            thread.join(5000);

            throw new Error("invokeAll stuck");

        }

    }

    /**

     * A helper class with a method to wait for a notification.

     *

     * The notification is received via the

     * {@code sendNotification} method.

     */

    static class NotificationReceiver {

        /** Has the notifiee been notified? */

        boolean notified = false;

        /**

         * Notify the notification receiver.

         */

        public synchronized void sendNotification() {

            notified = true;

            notifyAll();

        }

        /**

         * Waits until a notification has been received.

         *

         * @throws InterruptedException if the wait is interrupted

         */

        public synchronized void waitForNotification()

            throws InterruptedException {

            while (! notified)

                wait();

        }

    }

    /**

     * A callable task that blocks until it is interrupted.

     * This task sends a notification to a notification receiver when

     * it is first called.

     */

    static class BlockingTask implements Callable<Object> {

        private final NotificationReceiver notifiee;

        BlockingTask(NotificationReceiver notifiee) {

            this.notifiee = notifiee;

        }

        public Object call() throws InterruptedException {

            notifiee.sendNotification();

            // wait indefinitely until task is interrupted

            while (true) {

                synchronized (this) {

                    wait();

                }

            }

        }

    }

    /**

     * A callable task that simply returns a string result.

     */

    static class NonBlockingTask implements Callable<Object> {

        public Object call() {

            return "NonBlockingTaskResult";

        }

    }

    //--------------------- Infrastructure ---------------------------

    static volatile int passed = 0, failed = 0;

    static void pass() {passed++;}

    static void fail() {failed++; Thread.dumpStack();}

    static void fail(String msg) {System.out.println(msg); fail();}

    static void unexpected(Throwable t) {failed++; t.printStackTrace();}

    static void check(boolean cond) {if (cond) pass(); else fail();}

    static void equal(Object x, Object y) {

        if (x == null ? y == null : x.equals(y)) pass();

        else fail(x + " not equal to " + y);}

    public static void main(String[] args) throws Throwable {

        try {realMain(args);} catch (Throwable t) {unexpected(t);}

        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);

        if (failed > 0) throw new AssertionError("Some tests failed");}

}