/*

 * Copyright (c) 2006, 2011, 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 6399443

 * @run main/othervm/timeout=1000 AutoShutdown

 * @author Martin Buchholz

 */

import java.lang.ref.WeakReference;

import java.util.Arrays;

import java.util.concurrent.ConcurrentLinkedQueue;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.Executor;

import java.util.concurrent.TimeUnit;

public class AutoShutdown {

    static void await(CountDownLatch latch) throws InterruptedException {

            throw new AssertionError("timed out waiting for latch");

    }

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

        final Executor[] executors = {

            newSingleThreadExecutor(),

            newSingleThreadExecutor(defaultThreadFactory()),

            // TODO: should these executors also auto-shutdown?

            //newFixedThreadPool(1),

            //newSingleThreadScheduledExecutor(),

            //newSingleThreadScheduledExecutor(defaultThreadFactory()),

        };

        final ConcurrentLinkedQueue<WeakReference<Thread>> poolThreads

            = new ConcurrentLinkedQueue<>();

        final CountDownLatch threadStarted

            = new CountDownLatch(executors.length);

        final CountDownLatch pleaseProceed

            = new CountDownLatch(1);

        Runnable task = new Runnable() { public void run() {

            try {

                poolThreads.add(new WeakReference<>(Thread.currentThread()));

                threadStarted.countDown();

                await(pleaseProceed);

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

        }};

        for (Executor executor : executors)

            executor.execute(task);

        await(threadStarted);

        pleaseProceed.countDown();

        Arrays.fill(executors, null);   // make executors unreachable

        boolean done = false;

        for (long timeout = 1L; !done && timeout <= 128L; timeout *= 2) {

            System.gc();

            done = true;

            for (WeakReference<Thread> ref : poolThreads) {

                Thread thread = ref.get();

                if (thread != null) {

                    TimeUnit.SECONDS.timedJoin(thread, timeout);

                    if (thread.isAlive())

                        done = false;

                }

            }

        }

        if (!done)

            throw new AssertionError("pool threads did not terminate");

    }

    //--------------------- 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 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");}

}