/*

 * 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.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.Iterator;

import java.util.NoSuchElementException;

import java.util.concurrent.BlockingQueue;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.Executors;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.SynchronousQueue;

import junit.framework.Test;

public class SynchronousQueueTest extends JSR166TestCase {

    public static class Fair extends BlockingQueueTest {

        protected BlockingQueue emptyCollection() {

            return new SynchronousQueue(true);

        }

    }

    public static class NonFair extends BlockingQueueTest {

        protected BlockingQueue emptyCollection() {

            return new SynchronousQueue(false);

        }

    }

    public static void main(String[] args) {

        main(suite(), args);

    }

    public static Test suite() {

        return newTestSuite(SynchronousQueueTest.class,

                            new Fair().testSuite(),

                            new NonFair().testSuite());

    }

    /**

     * Any SynchronousQueue is both empty and full

     */

    public void testEmptyFull()      { testEmptyFull(false); }

    public void testEmptyFull_fair() { testEmptyFull(true); }

    public void testEmptyFull(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        assertTrue(q.isEmpty());

        assertEquals(0, q.size());

        assertEquals(0, q.remainingCapacity());

        assertFalse(q.offer(zero));

    }

    /**

     * offer fails if no active taker

     */

    public void testOffer()      { testOffer(false); }

    public void testOffer_fair() { testOffer(true); }

    public void testOffer(boolean fair) {

        SynchronousQueue q = new SynchronousQueue(fair);

        assertFalse(q.offer(one));

    }

    /**

     * add throws IllegalStateException if no active taker

     */

    public void testAdd()      { testAdd(false); }

    public void testAdd_fair() { testAdd(true); }

    public void testAdd(boolean fair) {

        SynchronousQueue q = new SynchronousQueue(fair);

        assertEquals(0, q.remainingCapacity());

        try {

            q.add(one);

            shouldThrow();

        } catch (IllegalStateException success) {}

    }

    /**

     * addAll(this) throws IllegalArgumentException

     */

    public void testAddAll_self()      { testAddAll_self(false); }

    public void testAddAll_self_fair() { testAddAll_self(true); }

    public void testAddAll_self(boolean fair) {

        SynchronousQueue q = new SynchronousQueue(fair);

        try {

            q.addAll(q);

            shouldThrow();

        } catch (IllegalArgumentException success) {}

    }

    /**

     * addAll throws IllegalStateException if no active taker

     */

    public void testAddAll_ISE()      { testAddAll_ISE(false); }

    public void testAddAll_ISE_fair() { testAddAll_ISE(true); }

    public void testAddAll_ISE(boolean fair) {

        SynchronousQueue q = new SynchronousQueue(fair);

        Integer[] ints = new Integer[1];

        for (int i = 0; i < ints.length; i++)

            ints[i] = i;

        Collection<Integer> coll = Arrays.asList(ints);

        try {

            q.addAll(coll);

            shouldThrow();

        } catch (IllegalStateException success) {}

    }

    /**

     * put blocks interruptibly if no active taker

     */

    public void testBlockingPut()      { testBlockingPut(false); }

    public void testBlockingPut_fair() { testBlockingPut(true); }

    public void testBlockingPut(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);

        Thread t = newStartedThread(new CheckedRunnable() {

            public void realRun() throws InterruptedException {

                Thread.currentThread().interrupt();

                try {

                    q.put(99);

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

                pleaseInterrupt.countDown();

                try {

                    q.put(99);

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

            }});

        await(pleaseInterrupt);

        t.interrupt();

        awaitTermination(t);

        assertEquals(0, q.remainingCapacity());

    }

    /**

     * put blocks interruptibly waiting for take

     */

    public void testPutWithTake()      { testPutWithTake(false); }

    public void testPutWithTake_fair() { testPutWithTake(true); }

    public void testPutWithTake(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        final CountDownLatch pleaseTake = new CountDownLatch(1);

        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);

        Thread t = newStartedThread(new CheckedRunnable() {

            public void realRun() throws InterruptedException {

                pleaseTake.countDown();

                q.put(one);

                Thread.currentThread().interrupt();

                try {

                    q.put(99);

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

                pleaseInterrupt.countDown();

                try {

                    q.put(99);

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

            }});

        await(pleaseTake);

        assertEquals(0, q.remainingCapacity());

        try { assertSame(one, q.take()); }

        catch (InterruptedException e) { threadUnexpectedException(e); }

        await(pleaseInterrupt);

        t.interrupt();

        awaitTermination(t);

        assertEquals(0, q.remainingCapacity());

    }

    /**

     * timed offer times out if elements not taken

     */

    public void testTimedOffer() {

        final SynchronousQueue q = new SynchronousQueue(fair);

        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);

        Thread t = newStartedThread(new CheckedRunnable() {

            public void realRun() throws InterruptedException {

                long startTime = System.nanoTime();

                assertFalse(q.offer(new Object(), timeoutMillis(), MILLISECONDS));

                assertTrue(millisElapsedSince(startTime) >= timeoutMillis());

                Thread.currentThread().interrupt();

                try {

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

                pleaseInterrupt.countDown();

                try {

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

            }});

        await(pleaseInterrupt);

        t.interrupt();

        awaitTermination(t);

    }

    /**

     * poll return null if no active putter

     */

    public void testPoll()      { testPoll(false); }

    public void testPoll_fair() { testPoll(true); }

    public void testPoll(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        assertNull(q.poll());

    }

    /**

     * timed poll with zero timeout times out if no active putter

     */

    public void testTimedPoll0()      { testTimedPoll0(false); }

    public void testTimedPoll0_fair() { testTimedPoll0(true); }

    public void testTimedPoll0(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        try { assertNull(q.poll(0, MILLISECONDS)); }

        catch (InterruptedException e) { threadUnexpectedException(e); }

    }

    /**

     * timed poll with nonzero timeout times out if no active putter

     */

    public void testTimedPoll() {

        final SynchronousQueue q = new SynchronousQueue(fair);

        final long startTime = System.nanoTime();

        try { assertNull(q.poll(timeoutMillis(), MILLISECONDS)); }

        catch (InterruptedException e) { threadUnexpectedException(e); }

        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());

    }

    /**

     * timed poll before a delayed offer times out, returning null;

     * after offer succeeds; on interruption throws

     */

    public void testTimedPollWithOffer() {

        final SynchronousQueue q = new SynchronousQueue(fair);

        final CountDownLatch pleaseOffer = new CountDownLatch(1);

        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);

        Thread t = newStartedThread(new CheckedRunnable() {

            public void realRun() throws InterruptedException {

                long startTime = System.nanoTime();

                assertNull(q.poll(timeoutMillis(), MILLISECONDS));

                assertTrue(millisElapsedSince(startTime) >= timeoutMillis());

                pleaseOffer.countDown();

                startTime = System.nanoTime();

                assertSame(zero, q.poll(LONG_DELAY_MS, MILLISECONDS));

                Thread.currentThread().interrupt();

                try {

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

                pleaseInterrupt.countDown();

                try {

                    q.poll(LONG_DELAY_MS, MILLISECONDS);

                    shouldThrow();

                } catch (InterruptedException success) {}

                assertFalse(Thread.interrupted());

                assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);

            }});

        await(pleaseOffer);

        long startTime = System.nanoTime();

        try { assertTrue(q.offer(zero, LONG_DELAY_MS, MILLISECONDS)); }

        catch (InterruptedException e) { threadUnexpectedException(e); }

        assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);

        await(pleaseInterrupt);

        t.interrupt();

        awaitTermination(t);

    }

    /**

     * peek() returns null if no active putter

     */

    public void testPeek()      { testPeek(false); }

    public void testPeek_fair() { testPeek(true); }

    public void testPeek(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        assertNull(q.peek());

    }

    /**

     * element() throws NoSuchElementException if no active putter

     */

    public void testElement()      { testElement(false); }

    public void testElement_fair() { testElement(true); }

    public void testElement(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        try {

            q.element();

            shouldThrow();

        } catch (NoSuchElementException success) {}

    }

    /**

     * remove() throws NoSuchElementException if no active putter

     */

    public void testRemove()      { testRemove(false); }

    public void testRemove_fair() { testRemove(true); }

    public void testRemove(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        try {

            q.remove();

            shouldThrow();

        } catch (NoSuchElementException success) {}

    }

    /**

     * contains returns false

     */

    public void testContains()      { testContains(false); }

    public void testContains_fair() { testContains(true); }

    public void testContains(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        assertFalse(q.contains(zero));

    }

    /**

     * clear ensures isEmpty

     */

    public void testClear()      { testClear(false); }

    public void testClear_fair() { testClear(true); }

    public void testClear(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        q.clear();

        assertTrue(q.isEmpty());

    }

    /**

     * containsAll returns false unless empty

     */

    public void testContainsAll()      { testContainsAll(false); }

    public void testContainsAll_fair() { testContainsAll(true); }

    public void testContainsAll(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        Integer[] empty = new Integer[0];

        assertTrue(q.containsAll(Arrays.asList(empty)));

        Integer[] ints = new Integer[1]; ints[0] = zero;

        assertFalse(q.containsAll(Arrays.asList(ints)));

    }

    /**

     * retainAll returns false

     */

    public void testRetainAll()      { testRetainAll(false); }

    public void testRetainAll_fair() { testRetainAll(true); }

    public void testRetainAll(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        Integer[] empty = new Integer[0];

        assertFalse(q.retainAll(Arrays.asList(empty)));

        Integer[] ints = new Integer[1]; ints[0] = zero;

        assertFalse(q.retainAll(Arrays.asList(ints)));

    }

    /**

     * removeAll returns false

     */

    public void testRemoveAll()      { testRemoveAll(false); }

    public void testRemoveAll_fair() { testRemoveAll(true); }

    public void testRemoveAll(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        Integer[] empty = new Integer[0];

        assertFalse(q.removeAll(Arrays.asList(empty)));

        Integer[] ints = new Integer[1]; ints[0] = zero;

        assertFalse(q.containsAll(Arrays.asList(ints)));

    }

    /**

     * toArray is empty

     */

    public void testToArray()      { testToArray(false); }

    public void testToArray_fair() { testToArray(true); }

    public void testToArray(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        Object[] o = q.toArray();

        assertEquals(0, o.length);

    }

    /**

     * toArray(Integer array) returns its argument with the first

     * element (if present) nulled out

     */

    public void testToArray2()      { testToArray2(false); }

    public void testToArray2_fair() { testToArray2(true); }

    public void testToArray2(boolean fair) {

        final SynchronousQueue<Integer> q = new SynchronousQueue<>(fair);

        Integer[] a;

        a = new Integer[0];

        assertSame(a, q.toArray(a));

        a = new Integer[3];

        Arrays.fill(a, 42);

        assertSame(a, q.toArray(a));

        assertNull(a[0]);

        for (int i = 1; i < a.length; i++)

            assertEquals(42, (int) a[i]);

    }

    /**

     * toArray(null) throws NPE

     */

    public void testToArray_null()      { testToArray_null(false); }

    public void testToArray_null_fair() { testToArray_null(true); }

    public void testToArray_null(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        try {

            Object[] o = q.toArray((Object[])null);

            shouldThrow();

        } catch (NullPointerException success) {}

    }

    /**

     * iterator does not traverse any elements

     */

    public void testIterator()      { testIterator(false); }

    public void testIterator_fair() { testIterator(true); }

    public void testIterator(boolean fair) {

        assertIteratorExhausted(new SynchronousQueue(fair).iterator());

    }

    /**

     * iterator remove throws IllegalStateException

     */

    public void testIteratorRemove()      { testIteratorRemove(false); }

    public void testIteratorRemove_fair() { testIteratorRemove(true); }

    public void testIteratorRemove(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        Iterator it = q.iterator();

        try {

            it.remove();

            shouldThrow();

        } catch (IllegalStateException success) {}

    }

    /**

     * toString returns a non-null string

     */

    public void testToString()      { testToString(false); }

    public void testToString_fair() { testToString(true); }

    public void testToString(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        String s = q.toString();

        assertNotNull(s);

    }

    /**

     * offer transfers elements across Executor tasks

     */

    public void testOfferInExecutor()      { testOfferInExecutor(false); }

    public void testOfferInExecutor_fair() { testOfferInExecutor(true); }

    public void testOfferInExecutor(boolean fair) {

        final SynchronousQueue q = new SynchronousQueue(fair);

        final CheckedBarrier threadsStarted = new CheckedBarrier(2);

        final ExecutorService executor = Executors.newFixedThreadPool(2);

        try (PoolCleaner cleaner = cleaner(executor)) {

            executor.execute(new CheckedRunnable() {

                public void realRun() throws InterruptedException {

                    assertFalse(q.offer(one));

                    threadsStarted.await();

                    assertTrue(q.offer(one, LONG_DELAY_MS, MILLISECONDS));

                    assertEquals(0, q.remainingCapacity());

                }});