/*

 * 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

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/*

 * 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 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/

 * Other contributors include Andrew Wright, Jeffrey Hayes,

 * Pat Fisher, Mike Judd.

 */

import static java.util.concurrent.TimeUnit.MILLISECONDS;

import java.util.concurrent.CountDownLatch;

import junit.framework.Test;

import junit.framework.TestSuite;

public class CountDownLatchTest extends JSR166TestCase {

    public static void main(String[] args) {

        main(suite(), args);

    }

    public static Test suite() {

        return new TestSuite(CountDownLatchTest.class);

    }

    /**

     * negative constructor argument throws IAE

     */

    public void testConstructor() {

        try {

            new CountDownLatch(-1);

            shouldThrow();

        } catch (IllegalArgumentException success) {}

    }

    /**

     * getCount returns initial count and decreases after countDown

     */

    public void testGetCount() {

        final CountDownLatch l = new CountDownLatch(2);

        assertEquals(2, l.getCount());

        l.countDown();

        assertEquals(1, l.getCount());

    }

    /**

     * countDown decrements count when positive and has no effect when zero

     */

    public void testCountDown() {

        final CountDownLatch l = new CountDownLatch(1);

        assertEquals(1, l.getCount());

        l.countDown();

        assertEquals(0, l.getCount());

        l.countDown();

        assertEquals(0, l.getCount());

    }

    /**

     * await returns after countDown to zero, but not before

     */

    public void testAwait() {

        final CountDownLatch l = new CountDownLatch(2);

        final CountDownLatch pleaseCountDown = new CountDownLatch(1);

        Thread t = newStartedThread(new CheckedRunnable() {

            public void realRun() throws InterruptedException {

                assertEquals(2, l.getCount());

                pleaseCountDown.countDown();

                l.await();

                assertEquals(0, l.getCount());

            }});

        await(pleaseCountDown);

        assertEquals(2, l.getCount());

        l.countDown();

        assertEquals(1, l.getCount());

        assertThreadStaysAlive(t);

        l.countDown();

        assertEquals(0, l.getCount());

        awaitTermination(t);

    }

    /**

     * timed await returns after countDown to zero

     */

    public void testTimedAwait() {

        final CountDownLatch l = new CountDownLatch(2);

        final CountDownLatch pleaseCountDown = new CountDownLatch(1);

        Thread t = newStartedThread(new CheckedRunnable() {

            public void realRun() throws InterruptedException {

                assertEquals(2, l.getCount());

                pleaseCountDown.countDown();

                assertTrue(l.await(LONG_DELAY_MS, MILLISECONDS));

                assertEquals(0, l.getCount());

            }});

        await(pleaseCountDown);

        assertEquals(2, l.getCount());

        l.countDown();

        assertEquals(1, l.getCount());

        assertThreadStaysAlive(t);

        l.countDown();

        assertEquals(0, l.getCount());

        awaitTermination(t);

    }

    /**

     * await throws IE if interrupted before counted down

     */

    public void testAwait_Interruptible() {

        final CountDownLatch l = new CountDownLatch(1);

        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);

        Thread t = newStartedThread(new CheckedRunnable() {

            public void realRun() throws InterruptedException {

                Thread.currentThread().interrupt();

                try {

                    l.await();

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

                pleaseInterrupt.countDown();

                try {

                    l.await();

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

                assertEquals(1, l.getCount());

            }});

        await(pleaseInterrupt);

        assertThreadStaysAlive(t);

        t.interrupt();

        awaitTermination(t);

    }

    /**

     * timed await throws IE if interrupted before counted down

     */

    public void testTimedAwait_Interruptible() {

        final CountDownLatch l = new CountDownLatch(1);

        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);

        Thread t = newStartedThread(new CheckedRunnable() {

            public void realRun() throws InterruptedException {

                Thread.currentThread().interrupt();

                try {

                    l.await(LONG_DELAY_MS, MILLISECONDS);

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

                pleaseInterrupt.countDown();

                try {

                    l.await(LONG_DELAY_MS, MILLISECONDS);

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

                assertEquals(1, l.getCount());

            }});

        await(pleaseInterrupt);

        assertThreadStaysAlive(t);

        t.interrupt();

        awaitTermination(t);

    }

    /**

     * timed await times out if not counted down before timeout

     */

    public void testAwaitTimeout() throws InterruptedException {

        final CountDownLatch l = new CountDownLatch(1);

        Thread t = newStartedThread(new CheckedRunnable() {

            public void realRun() throws InterruptedException {

                assertEquals(1, l.getCount());

                assertFalse(l.await(timeoutMillis(), MILLISECONDS));

                assertEquals(1, l.getCount());

            }});

        awaitTermination(t);

        assertEquals(1, l.getCount());

    }

    /**

     * toString indicates current count

     */

    public void testToString() {

        CountDownLatch s = new CountDownLatch(2);

        assertTrue(s.toString().contains("Count = 2"));

        s.countDown();

        assertTrue(s.toString().contains("Count = 1"));

        s.countDown();

        assertTrue(s.toString().contains("Count = 0"));

    }

}