test/tck/SynchronousQueueTest.java

/*
 * 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 java.util.concurrent.ThreadLocalRandom;

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 ISE 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);
        assertThreadBlocks(t, Thread.State.WAITING);
        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);
        assertThreadBlocks(t, Thread.State.WAITING);
        t.interrupt();
        awaitTermination(t);
        assertEquals(0, q.remainingCapacity());
    }

    /**
     * timed offer times out if elements not taken
     */
    public void testTimedOffer() {
        final boolean fair = ThreadLocalRandom.current().nextBoolean();
        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());
                pleaseInterrupt.countDown();
                try {
                    q.offer(new Object(), 2 * LONG_DELAY_MS, MILLISECONDS);
                    shouldThrow();
                } catch (InterruptedException success) {}
                assertFalse(Thread.interrupted());
            }});

        await(pleaseInterrupt);
        assertThreadBlocks(t, Thread.State.TIMED_WAITING);
        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 boolean fair = ThreadLocalRandom.current().nextBoolean();
        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 boolean fair = ThreadLocalRandom.current().nextBoolean();
        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 {
                    q.poll(LONG_DELAY_MS, MILLISECONDS);
                    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);
        assertThreadBlocks(t, Thread.State.TIMED_WAITING);
        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(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 ISE
     */
    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());
                }});

            executor.execute(new CheckedRunnable() {
                public void realRun() throws InterruptedException {
                    threadsStarted.await();
                    assertSame(one, q.take());
                }});
        }
    }

    /**
     * timed poll retrieves elements across Executor threads
     */
    public void testPollInExecutor()      { testPollInExecutor(false); }
    public void testPollInExecutor_fair() { testPollInExecutor(true); }
    public void testPollInExecutor(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 {
                    assertNull(q.poll());
                    threadsStarted.await();
                    assertSame(one, q.poll(LONG_DELAY_MS, MILLISECONDS));
                    assertTrue(q.isEmpty());
                }});

            executor.execute(new CheckedRunnable() {
                public void realRun() throws InterruptedException {
                    threadsStarted.await();
                    q.put(one);
                }});
        }
    }

    /**
     * a deserialized serialized queue is usable
     */
    public void testSerialization() {
        final SynchronousQueue x = new SynchronousQueue();
        final SynchronousQueue y = new SynchronousQueue(false);
        final SynchronousQueue z = new SynchronousQueue(true);
        assertSerialEquals(x, y);
        assertNotSerialEquals(x, z);
        SynchronousQueue[] qs = { x, y, z };
        for (SynchronousQueue q : qs) {
            SynchronousQueue clone = serialClone(q);
            assertNotSame(q, clone);
            assertSerialEquals(q, clone);
            assertTrue(clone.isEmpty());
            assertEquals(0, clone.size());
            assertEquals(0, clone.remainingCapacity());
            assertFalse(clone.offer(zero));
        }
    }

    /**
     * drainTo(c) of empty queue doesn't transfer elements
     */
    public void testDrainTo()      { testDrainTo(false); }
    public void testDrainTo_fair() { testDrainTo(true); }
    public void testDrainTo(boolean fair) {
        final SynchronousQueue q = new SynchronousQueue(fair);
        ArrayList l = new ArrayList();
        q.drainTo(l);
        assertEquals(0, q.size());
        assertEquals(0, l.size());
    }

    /**
     * drainTo empties queue, unblocking a waiting put.
     */
    public void testDrainToWithActivePut()      { testDrainToWithActivePut(false); }
    public void testDrainToWithActivePut_fair() { testDrainToWithActivePut(true); }
    public void testDrainToWithActivePut(boolean fair) {
        final SynchronousQueue q = new SynchronousQueue(fair);
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() throws InterruptedException {
                q.put(one);
            }});

        ArrayList l = new ArrayList();
        long startTime = System.nanoTime();
        while (l.isEmpty()) {
            q.drainTo(l);
            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
                fail("timed out");
            Thread.yield();
        }
        assertEquals(1, l.size());
        assertSame(one, l.get(0));
        awaitTermination(t);
    }

    /**
     * drainTo(c, n) empties up to n elements of queue into c
     */
    public void testDrainToN() throws InterruptedException {
        final SynchronousQueue q = new SynchronousQueue();
        Thread t1 = newStartedThread(new CheckedRunnable() {
            public void realRun() throws InterruptedException {
                q.put(one);
            }});

        Thread t2 = newStartedThread(new CheckedRunnable() {
            public void realRun() throws InterruptedException {
                q.put(two);
            }});

        ArrayList l = new ArrayList();
        int drained;
        while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
        assertEquals(1, drained);
        assertEquals(1, l.size());
        while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
        assertEquals(1, drained);
        assertEquals(2, l.size());
        assertTrue(l.contains(one));
        assertTrue(l.contains(two));
        awaitTermination(t1);
        awaitTermination(t2);
    }

    /**
     * remove(null), contains(null) always return false
     */
    public void testNeverContainsNull() {
        Collection<?> q = new SynchronousQueue();
        assertFalse(q.contains(null));
        assertFalse(q.remove(null));
    }

}
Revision:	1.58
Committed:	Sun May 14 04:02:06 2017 UTC (7 years ago) by jsr166
Branch:	MAIN
Changes since 1.57:	+7 -0 lines
Log Message:	improve testPutWithTake
#	Content
1	/*
2	* Written by Doug Lea with assistance from members of JCP JSR-166
3	* Expert Group and released to the public domain, as explained at
4	* http://creativecommons.org/publicdomain/zero/1.0/
5	* Other contributors include Andrew Wright, Jeffrey Hayes,
6	* Pat Fisher, Mike Judd.
7	*/
8
9	import static java.util.concurrent.TimeUnit.MILLISECONDS;
10
11	import java.util.ArrayList;
12	import java.util.Arrays;
13	import java.util.Collection;
14	import java.util.Iterator;
15	import java.util.NoSuchElementException;
16	import java.util.concurrent.BlockingQueue;
17	import java.util.concurrent.CountDownLatch;
18	import java.util.concurrent.Executors;
19	import java.util.concurrent.ExecutorService;
20	import java.util.concurrent.SynchronousQueue;
21	import java.util.concurrent.ThreadLocalRandom;
22
23	import junit.framework.Test;
24
25	public class SynchronousQueueTest extends JSR166TestCase {
26
27	public static class Fair extends BlockingQueueTest {
28	protected BlockingQueue emptyCollection() {
29	return new SynchronousQueue(true);
30	}
31	}
32
33	public static class NonFair extends BlockingQueueTest {
34	protected BlockingQueue emptyCollection() {
35	return new SynchronousQueue(false);
36	}
37	}
38
39	public static void main(String[] args) {
40	main(suite(), args);
41	}
42
43	public static Test suite() {
44	return newTestSuite(SynchronousQueueTest.class,
45	new Fair().testSuite(),
46	new NonFair().testSuite());
47	}
48
49	/**
50	* Any SynchronousQueue is both empty and full
51	*/
52	public void testEmptyFull() { testEmptyFull(false); }
53	public void testEmptyFull_fair() { testEmptyFull(true); }
54	public void testEmptyFull(boolean fair) {
55	final SynchronousQueue q = new SynchronousQueue(fair);
56	assertTrue(q.isEmpty());
57	assertEquals(0, q.size());
58	assertEquals(0, q.remainingCapacity());
59	assertFalse(q.offer(zero));
60	}
61
62	/**
63	* offer fails if no active taker
64	*/
65	public void testOffer() { testOffer(false); }
66	public void testOffer_fair() { testOffer(true); }
67	public void testOffer(boolean fair) {
68	SynchronousQueue q = new SynchronousQueue(fair);
69	assertFalse(q.offer(one));
70	}
71
72	/**
73	* add throws IllegalStateException if no active taker
74	*/
75	public void testAdd() { testAdd(false); }
76	public void testAdd_fair() { testAdd(true); }
77	public void testAdd(boolean fair) {
78	SynchronousQueue q = new SynchronousQueue(fair);
79	assertEquals(0, q.remainingCapacity());
80	try {
81	q.add(one);
82	shouldThrow();
83	} catch (IllegalStateException success) {}
84	}
85
86	/**
87	* addAll(this) throws IllegalArgumentException
88	*/
89	public void testAddAll_self() { testAddAll_self(false); }
90	public void testAddAll_self_fair() { testAddAll_self(true); }
91	public void testAddAll_self(boolean fair) {
92	SynchronousQueue q = new SynchronousQueue(fair);
93	try {
94	q.addAll(q);
95	shouldThrow();
96	} catch (IllegalArgumentException success) {}
97	}
98
99	/**
100	* addAll throws ISE if no active taker
101	*/
102	public void testAddAll_ISE() { testAddAll_ISE(false); }
103	public void testAddAll_ISE_fair() { testAddAll_ISE(true); }
104	public void testAddAll_ISE(boolean fair) {
105	SynchronousQueue q = new SynchronousQueue(fair);
106	Integer[] ints = new Integer[1];
107	for (int i = 0; i < ints.length; i++)
108	ints[i] = i;
109	Collection<Integer> coll = Arrays.asList(ints);
110	try {
111	q.addAll(coll);
112	shouldThrow();
113	} catch (IllegalStateException success) {}
114	}
115
116	/**
117	* put blocks interruptibly if no active taker
118	*/
119	public void testBlockingPut() { testBlockingPut(false); }
120	public void testBlockingPut_fair() { testBlockingPut(true); }
121	public void testBlockingPut(boolean fair) {
122	final SynchronousQueue q = new SynchronousQueue(fair);
123	final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
124	Thread t = newStartedThread(new CheckedRunnable() {
125	public void realRun() throws InterruptedException {
126	Thread.currentThread().interrupt();
127	try {
128	q.put(99);
129	shouldThrow();
130	} catch (InterruptedException success) {}
131	assertFalse(Thread.interrupted());
132
133	pleaseInterrupt.countDown();
134	try {
135	q.put(99);
136	shouldThrow();
137	} catch (InterruptedException success) {}
138	assertFalse(Thread.interrupted());
139	}});
140
141	await(pleaseInterrupt);
142	assertThreadBlocks(t, Thread.State.WAITING);
143	t.interrupt();
144	awaitTermination(t);
145	assertEquals(0, q.remainingCapacity());
146	}
147
148	/**
149	* put blocks interruptibly waiting for take
150	*/
151	public void testPutWithTake() { testPutWithTake(false); }
152	public void testPutWithTake_fair() { testPutWithTake(true); }
153	public void testPutWithTake(boolean fair) {
154	final SynchronousQueue q = new SynchronousQueue(fair);
155	final CountDownLatch pleaseTake = new CountDownLatch(1);
156	final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
157	Thread t = newStartedThread(new CheckedRunnable() {
158	public void realRun() throws InterruptedException {
159	pleaseTake.countDown();
160	q.put(one);
161
162	Thread.currentThread().interrupt();
163	try {
164	q.put(99);
165	shouldThrow();
166	} catch (InterruptedException success) {}
167	assertFalse(Thread.interrupted());
168
169	pleaseInterrupt.countDown();
170	try {
171	q.put(99);
172	shouldThrow();
173	} catch (InterruptedException success) {}
174	assertFalse(Thread.interrupted());
175	}});
176
177	await(pleaseTake);
178	assertEquals(0, q.remainingCapacity());
179	try { assertSame(one, q.take()); }
180	catch (InterruptedException e) { threadUnexpectedException(e); }
181
182	await(pleaseInterrupt);
183	assertThreadBlocks(t, Thread.State.WAITING);
184	t.interrupt();
185	awaitTermination(t);
186	assertEquals(0, q.remainingCapacity());
187	}
188
189	/**
190	* timed offer times out if elements not taken
191	*/
192	public void testTimedOffer() {
193	final boolean fair = ThreadLocalRandom.current().nextBoolean();
194	final SynchronousQueue q = new SynchronousQueue(fair);
195	final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
196	Thread t = newStartedThread(new CheckedRunnable() {
197	public void realRun() throws InterruptedException {
198	long startTime = System.nanoTime();
199	assertFalse(q.offer(new Object(), timeoutMillis(), MILLISECONDS));
200	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
201	pleaseInterrupt.countDown();
202	try {
203	q.offer(new Object(), 2 * LONG_DELAY_MS, MILLISECONDS);
204	shouldThrow();
205	} catch (InterruptedException success) {}
206	assertFalse(Thread.interrupted());
207	}});
208
209	await(pleaseInterrupt);
210	assertThreadBlocks(t, Thread.State.TIMED_WAITING);
211	t.interrupt();
212	awaitTermination(t);
213	}
214
215	/**
216	* poll return null if no active putter
217	*/
218	public void testPoll() { testPoll(false); }
219	public void testPoll_fair() { testPoll(true); }
220	public void testPoll(boolean fair) {
221	final SynchronousQueue q = new SynchronousQueue(fair);
222	assertNull(q.poll());
223	}
224
225	/**
226	* timed poll with zero timeout times out if no active putter
227	*/
228	public void testTimedPoll0() { testTimedPoll0(false); }
229	public void testTimedPoll0_fair() { testTimedPoll0(true); }
230	public void testTimedPoll0(boolean fair) {
231	final SynchronousQueue q = new SynchronousQueue(fair);
232	try { assertNull(q.poll(0, MILLISECONDS)); }
233	catch (InterruptedException e) { threadUnexpectedException(e); }
234	}
235
236	/**
237	* timed poll with nonzero timeout times out if no active putter
238	*/
239	public void testTimedPoll() {
240	final boolean fair = ThreadLocalRandom.current().nextBoolean();
241	final SynchronousQueue q = new SynchronousQueue(fair);
242	final long startTime = System.nanoTime();
243	try { assertNull(q.poll(timeoutMillis(), MILLISECONDS)); }
244	catch (InterruptedException e) { threadUnexpectedException(e); }
245	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
246	}
247
248	/**
249	* timed poll before a delayed offer times out, returning null;
250	* after offer succeeds; on interruption throws
251	*/
252	public void testTimedPollWithOffer() {
253	final boolean fair = ThreadLocalRandom.current().nextBoolean();
254	final SynchronousQueue q = new SynchronousQueue(fair);
255	final CountDownLatch pleaseOffer = new CountDownLatch(1);
256	final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
257	Thread t = newStartedThread(new CheckedRunnable() {
258	public void realRun() throws InterruptedException {
259	long startTime = System.nanoTime();
260	assertNull(q.poll(timeoutMillis(), MILLISECONDS));
261	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
262
263	pleaseOffer.countDown();
264	startTime = System.nanoTime();
265	assertSame(zero, q.poll(LONG_DELAY_MS, MILLISECONDS));
266
267	Thread.currentThread().interrupt();
268	try {
269	q.poll(LONG_DELAY_MS, MILLISECONDS);
270	shouldThrow();
271	} catch (InterruptedException success) {}
272	assertFalse(Thread.interrupted());
273
274	pleaseInterrupt.countDown();
275	try {
276	q.poll(LONG_DELAY_MS, MILLISECONDS);
277	shouldThrow();
278	} catch (InterruptedException success) {}
279	assertFalse(Thread.interrupted());
280
281	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
282	}});
283
284	await(pleaseOffer);
285	long startTime = System.nanoTime();
286	try { assertTrue(q.offer(zero, LONG_DELAY_MS, MILLISECONDS)); }
287	catch (InterruptedException e) { threadUnexpectedException(e); }
288	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
289
290	await(pleaseInterrupt);
291	assertThreadBlocks(t, Thread.State.TIMED_WAITING);
292	t.interrupt();
293	awaitTermination(t);
294	}
295
296	/**
297	* peek() returns null if no active putter
298	*/
299	public void testPeek() { testPeek(false); }
300	public void testPeek_fair() { testPeek(true); }
301	public void testPeek(boolean fair) {
302	final SynchronousQueue q = new SynchronousQueue(fair);
303	assertNull(q.peek());
304	}
305
306	/**
307	* element() throws NoSuchElementException if no active putter
308	*/
309	public void testElement() { testElement(false); }
310	public void testElement_fair() { testElement(true); }
311	public void testElement(boolean fair) {
312	final SynchronousQueue q = new SynchronousQueue(fair);
313	try {
314	q.element();
315	shouldThrow();
316	} catch (NoSuchElementException success) {}
317	}
318
319	/**
320	* remove() throws NoSuchElementException if no active putter
321	*/
322	public void testRemove() { testRemove(false); }
323	public void testRemove_fair() { testRemove(true); }
324	public void testRemove(boolean fair) {
325	final SynchronousQueue q = new SynchronousQueue(fair);
326	try {
327	q.remove();
328	shouldThrow();
329	} catch (NoSuchElementException success) {}
330	}
331
332	/**
333	* contains returns false
334	*/
335	public void testContains() { testContains(false); }
336	public void testContains_fair() { testContains(true); }
337	public void testContains(boolean fair) {
338	final SynchronousQueue q = new SynchronousQueue(fair);
339	assertFalse(q.contains(zero));
340	}
341
342	/**
343	* clear ensures isEmpty
344	*/
345	public void testClear() { testClear(false); }
346	public void testClear_fair() { testClear(true); }
347	public void testClear(boolean fair) {
348	final SynchronousQueue q = new SynchronousQueue(fair);
349	q.clear();
350	assertTrue(q.isEmpty());
351	}
352
353	/**
354	* containsAll returns false unless empty
355	*/
356	public void testContainsAll() { testContainsAll(false); }
357	public void testContainsAll_fair() { testContainsAll(true); }
358	public void testContainsAll(boolean fair) {
359	final SynchronousQueue q = new SynchronousQueue(fair);
360	Integer[] empty = new Integer[0];
361	assertTrue(q.containsAll(Arrays.asList(empty)));
362	Integer[] ints = new Integer[1]; ints[0] = zero;
363	assertFalse(q.containsAll(Arrays.asList(ints)));
364	}
365
366	/**
367	* retainAll returns false
368	*/
369	public void testRetainAll() { testRetainAll(false); }
370	public void testRetainAll_fair() { testRetainAll(true); }
371	public void testRetainAll(boolean fair) {
372	final SynchronousQueue q = new SynchronousQueue(fair);
373	Integer[] empty = new Integer[0];
374	assertFalse(q.retainAll(Arrays.asList(empty)));
375	Integer[] ints = new Integer[1]; ints[0] = zero;
376	assertFalse(q.retainAll(Arrays.asList(ints)));
377	}
378
379	/**
380	* removeAll returns false
381	*/
382	public void testRemoveAll() { testRemoveAll(false); }
383	public void testRemoveAll_fair() { testRemoveAll(true); }
384	public void testRemoveAll(boolean fair) {
385	final SynchronousQueue q = new SynchronousQueue(fair);
386	Integer[] empty = new Integer[0];
387	assertFalse(q.removeAll(Arrays.asList(empty)));
388	Integer[] ints = new Integer[1]; ints[0] = zero;
389	assertFalse(q.containsAll(Arrays.asList(ints)));
390	}
391
392	/**
393	* toArray is empty
394	*/
395	public void testToArray() { testToArray(false); }
396	public void testToArray_fair() { testToArray(true); }
397	public void testToArray(boolean fair) {
398	final SynchronousQueue q = new SynchronousQueue(fair);
399	Object[] o = q.toArray();
400	assertEquals(0, o.length);
401	}
402
403	/**
404	* toArray(Integer array) returns its argument with the first
405	* element (if present) nulled out
406	*/
407	public void testToArray2() { testToArray2(false); }
408	public void testToArray2_fair() { testToArray2(true); }
409	public void testToArray2(boolean fair) {
410	final SynchronousQueue<Integer> q = new SynchronousQueue<>(fair);
411	Integer[] a;
412
413	a = new Integer[0];
414	assertSame(a, q.toArray(a));
415
416	a = new Integer[3];
417	Arrays.fill(a, 42);
418	assertSame(a, q.toArray(a));
419	assertNull(a[0]);
420	for (int i = 1; i < a.length; i++)
421	assertEquals(42, (int) a[i]);
422	}
423
424	/**
425	* toArray(null) throws NPE
426	*/
427	public void testToArray_null() { testToArray_null(false); }
428	public void testToArray_null_fair() { testToArray_null(true); }
429	public void testToArray_null(boolean fair) {
430	final SynchronousQueue q = new SynchronousQueue(fair);
431	try {
432	Object[] o = q.toArray(null);
433	shouldThrow();
434	} catch (NullPointerException success) {}
435	}
436
437	/**
438	* iterator does not traverse any elements
439	*/
440	public void testIterator() { testIterator(false); }
441	public void testIterator_fair() { testIterator(true); }
442	public void testIterator(boolean fair) {
443	assertIteratorExhausted(new SynchronousQueue(fair).iterator());
444	}
445
446	/**
447	* iterator remove throws ISE
448	*/
449	public void testIteratorRemove() { testIteratorRemove(false); }
450	public void testIteratorRemove_fair() { testIteratorRemove(true); }
451	public void testIteratorRemove(boolean fair) {
452	final SynchronousQueue q = new SynchronousQueue(fair);
453	Iterator it = q.iterator();
454	try {
455	it.remove();
456	shouldThrow();
457	} catch (IllegalStateException success) {}
458	}
459
460	/**
461	* toString returns a non-null string
462	*/
463	public void testToString() { testToString(false); }
464	public void testToString_fair() { testToString(true); }
465	public void testToString(boolean fair) {
466	final SynchronousQueue q = new SynchronousQueue(fair);
467	String s = q.toString();
468	assertNotNull(s);
469	}
470
471	/**
472	* offer transfers elements across Executor tasks
473	*/
474	public void testOfferInExecutor() { testOfferInExecutor(false); }
475	public void testOfferInExecutor_fair() { testOfferInExecutor(true); }
476	public void testOfferInExecutor(boolean fair) {
477	final SynchronousQueue q = new SynchronousQueue(fair);
478	final CheckedBarrier threadsStarted = new CheckedBarrier(2);
479	final ExecutorService executor = Executors.newFixedThreadPool(2);
480	try (PoolCleaner cleaner = cleaner(executor)) {
481
482	executor.execute(new CheckedRunnable() {
483	public void realRun() throws InterruptedException {
484	assertFalse(q.offer(one));
485	threadsStarted.await();
486	assertTrue(q.offer(one, LONG_DELAY_MS, MILLISECONDS));
487	assertEquals(0, q.remainingCapacity());
488	}});
489
490	executor.execute(new CheckedRunnable() {
491	public void realRun() throws InterruptedException {
492	threadsStarted.await();
493	assertSame(one, q.take());
494	}});
495	}
496	}
497
498	/**
499	* timed poll retrieves elements across Executor threads
500	*/
501	public void testPollInExecutor() { testPollInExecutor(false); }
502	public void testPollInExecutor_fair() { testPollInExecutor(true); }
503	public void testPollInExecutor(boolean fair) {
504	final SynchronousQueue q = new SynchronousQueue(fair);
505	final CheckedBarrier threadsStarted = new CheckedBarrier(2);
506	final ExecutorService executor = Executors.newFixedThreadPool(2);
507	try (PoolCleaner cleaner = cleaner(executor)) {
508	executor.execute(new CheckedRunnable() {
509	public void realRun() throws InterruptedException {
510	assertNull(q.poll());
511	threadsStarted.await();
512	assertSame(one, q.poll(LONG_DELAY_MS, MILLISECONDS));
513	assertTrue(q.isEmpty());
514	}});
515
516	executor.execute(new CheckedRunnable() {
517	public void realRun() throws InterruptedException {
518	threadsStarted.await();
519	q.put(one);
520	}});
521	}
522	}
523
524	/**
525	* a deserialized serialized queue is usable
526	*/
527	public void testSerialization() {
528	final SynchronousQueue x = new SynchronousQueue();
529	final SynchronousQueue y = new SynchronousQueue(false);
530	final SynchronousQueue z = new SynchronousQueue(true);
531	assertSerialEquals(x, y);
532	assertNotSerialEquals(x, z);
533	SynchronousQueue[] qs = { x, y, z };
534	for (SynchronousQueue q : qs) {
535	SynchronousQueue clone = serialClone(q);
536	assertNotSame(q, clone);
537	assertSerialEquals(q, clone);
538	assertTrue(clone.isEmpty());
539	assertEquals(0, clone.size());
540	assertEquals(0, clone.remainingCapacity());
541	assertFalse(clone.offer(zero));
542	}
543	}
544
545	/**
546	* drainTo(c) of empty queue doesn't transfer elements
547	*/
548	public void testDrainTo() { testDrainTo(false); }
549	public void testDrainTo_fair() { testDrainTo(true); }
550	public void testDrainTo(boolean fair) {
551	final SynchronousQueue q = new SynchronousQueue(fair);
552	ArrayList l = new ArrayList();
553	q.drainTo(l);
554	assertEquals(0, q.size());
555	assertEquals(0, l.size());
556	}
557
558	/**
559	* drainTo empties queue, unblocking a waiting put.
560	*/
561	public void testDrainToWithActivePut() { testDrainToWithActivePut(false); }
562	public void testDrainToWithActivePut_fair() { testDrainToWithActivePut(true); }
563	public void testDrainToWithActivePut(boolean fair) {
564	final SynchronousQueue q = new SynchronousQueue(fair);
565	Thread t = newStartedThread(new CheckedRunnable() {
566	public void realRun() throws InterruptedException {
567	q.put(one);
568	}});
569
570	ArrayList l = new ArrayList();
571	long startTime = System.nanoTime();
572	while (l.isEmpty()) {
573	q.drainTo(l);
574	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
575	fail("timed out");
576	Thread.yield();
577	}
578	assertEquals(1, l.size());
579	assertSame(one, l.get(0));
580	awaitTermination(t);
581	}
582
583	/**
584	* drainTo(c, n) empties up to n elements of queue into c
585	*/
586	public void testDrainToN() throws InterruptedException {
587	final SynchronousQueue q = new SynchronousQueue();
588	Thread t1 = newStartedThread(new CheckedRunnable() {
589	public void realRun() throws InterruptedException {
590	q.put(one);
591	}});
592
593	Thread t2 = newStartedThread(new CheckedRunnable() {
594	public void realRun() throws InterruptedException {
595	q.put(two);
596	}});
597
598	ArrayList l = new ArrayList();
599	int drained;
600	while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
601	assertEquals(1, drained);
602	assertEquals(1, l.size());
603	while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
604	assertEquals(1, drained);
605	assertEquals(2, l.size());
606	assertTrue(l.contains(one));
607	assertTrue(l.contains(two));
608	awaitTermination(t1);
609	awaitTermination(t2);
610	}
611
612	/**
613	* remove(null), contains(null) always return false
614	*/
615	public void testNeverContainsNull() {
616	Collection<?> q = new SynchronousQueue();
617	assertFalse(q.contains(null));
618	assertFalse(q.remove(null));
619	}
620
621	}