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 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);
        if (randomBoolean()) 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);
        if (randomBoolean()) 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());

                Thread.currentThread().interrupt();
                try {
                    q.offer(new Object(), randomTimeout(), randomTimeUnit());
                    shouldThrow();
                } catch (InterruptedException success) {}
                assertFalse(Thread.interrupted());

                pleaseInterrupt.countDown();
                try {
                    q.offer(new Object(), LONG_DELAY_MS, MILLISECONDS);
                    shouldThrow();
                } catch (InterruptedException success) {}
                assertFalse(Thread.interrupted());

                assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
            }});

        await(pleaseInterrupt);
        if (randomBoolean()) 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(randomTimeout(), randomTimeUnit());
                    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);
        if (randomBoolean()) 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((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());
                }});

            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/reserialized 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:	1.63
Committed:	Sun Aug 11 22:29:27 2019 UTC (4 years, 9 months ago) by jsr166
Branch:	MAIN
Changes since 1.62:	+10 -7 lines
Log Message:	more assertions; more interleavings
#	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 IllegalStateException 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	if (randomBoolean()) 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	if (randomBoolean()) 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
200	assertFalse(q.offer(new Object(), timeoutMillis(), MILLISECONDS));
201	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
202
203	Thread.currentThread().interrupt();
204	try {
205	q.offer(new Object(), randomTimeout(), randomTimeUnit());
206	shouldThrow();
207	} catch (InterruptedException success) {}
208	assertFalse(Thread.interrupted());
209
210	pleaseInterrupt.countDown();
211	try {
212	q.offer(new Object(), LONG_DELAY_MS, MILLISECONDS);
213	shouldThrow();
214	} catch (InterruptedException success) {}
215	assertFalse(Thread.interrupted());
216
217	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
218	}});
219
220	await(pleaseInterrupt);
221	if (randomBoolean()) assertThreadBlocks(t, Thread.State.TIMED_WAITING);
222	t.interrupt();
223	awaitTermination(t);
224	}
225
226	/**
227	* poll return null if no active putter
228	*/
229	public void testPoll() { testPoll(false); }
230	public void testPoll_fair() { testPoll(true); }
231	public void testPoll(boolean fair) {
232	final SynchronousQueue q = new SynchronousQueue(fair);
233	assertNull(q.poll());
234	}
235
236	/**
237	* timed poll with zero timeout times out if no active putter
238	*/
239	public void testTimedPoll0() { testTimedPoll0(false); }
240	public void testTimedPoll0_fair() { testTimedPoll0(true); }
241	public void testTimedPoll0(boolean fair) {
242	final SynchronousQueue q = new SynchronousQueue(fair);
243	try { assertNull(q.poll(0, MILLISECONDS)); }
244	catch (InterruptedException e) { threadUnexpectedException(e); }
245	}
246
247	/**
248	* timed poll with nonzero timeout times out if no active putter
249	*/
250	public void testTimedPoll() {
251	final boolean fair = ThreadLocalRandom.current().nextBoolean();
252	final SynchronousQueue q = new SynchronousQueue(fair);
253	final long startTime = System.nanoTime();
254	try { assertNull(q.poll(timeoutMillis(), MILLISECONDS)); }
255	catch (InterruptedException e) { threadUnexpectedException(e); }
256	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
257	}
258
259	/**
260	* timed poll before a delayed offer times out, returning null;
261	* after offer succeeds; on interruption throws
262	*/
263	public void testTimedPollWithOffer() {
264	final boolean fair = ThreadLocalRandom.current().nextBoolean();
265	final SynchronousQueue q = new SynchronousQueue(fair);
266	final CountDownLatch pleaseOffer = new CountDownLatch(1);
267	final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
268	Thread t = newStartedThread(new CheckedRunnable() {
269	public void realRun() throws InterruptedException {
270	long startTime = System.nanoTime();
271	assertNull(q.poll(timeoutMillis(), MILLISECONDS));
272	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
273
274	pleaseOffer.countDown();
275	startTime = System.nanoTime();
276	assertSame(zero, q.poll(LONG_DELAY_MS, MILLISECONDS));
277
278	Thread.currentThread().interrupt();
279	try {
280	q.poll(randomTimeout(), randomTimeUnit());
281	shouldThrow();
282	} catch (InterruptedException success) {}
283	assertFalse(Thread.interrupted());
284
285	pleaseInterrupt.countDown();
286	try {
287	q.poll(LONG_DELAY_MS, MILLISECONDS);
288	shouldThrow();
289	} catch (InterruptedException success) {}
290	assertFalse(Thread.interrupted());
291
292	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
293	}});
294
295	await(pleaseOffer);
296	long startTime = System.nanoTime();
297	try { assertTrue(q.offer(zero, LONG_DELAY_MS, MILLISECONDS)); }
298	catch (InterruptedException e) { threadUnexpectedException(e); }
299	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
300
301	await(pleaseInterrupt);
302	if (randomBoolean()) assertThreadBlocks(t, Thread.State.TIMED_WAITING);
303	t.interrupt();
304	awaitTermination(t);
305	}
306
307	/**
308	* peek() returns null if no active putter
309	*/
310	public void testPeek() { testPeek(false); }
311	public void testPeek_fair() { testPeek(true); }
312	public void testPeek(boolean fair) {
313	final SynchronousQueue q = new SynchronousQueue(fair);
314	assertNull(q.peek());
315	}
316
317	/**
318	* element() throws NoSuchElementException if no active putter
319	*/
320	public void testElement() { testElement(false); }
321	public void testElement_fair() { testElement(true); }
322	public void testElement(boolean fair) {
323	final SynchronousQueue q = new SynchronousQueue(fair);
324	try {
325	q.element();
326	shouldThrow();
327	} catch (NoSuchElementException success) {}
328	}
329
330	/**
331	* remove() throws NoSuchElementException if no active putter
332	*/
333	public void testRemove() { testRemove(false); }
334	public void testRemove_fair() { testRemove(true); }
335	public void testRemove(boolean fair) {
336	final SynchronousQueue q = new SynchronousQueue(fair);
337	try {
338	q.remove();
339	shouldThrow();
340	} catch (NoSuchElementException success) {}
341	}
342
343	/**
344	* contains returns false
345	*/
346	public void testContains() { testContains(false); }
347	public void testContains_fair() { testContains(true); }
348	public void testContains(boolean fair) {
349	final SynchronousQueue q = new SynchronousQueue(fair);
350	assertFalse(q.contains(zero));
351	}
352
353	/**
354	* clear ensures isEmpty
355	*/
356	public void testClear() { testClear(false); }
357	public void testClear_fair() { testClear(true); }
358	public void testClear(boolean fair) {
359	final SynchronousQueue q = new SynchronousQueue(fair);
360	q.clear();
361	assertTrue(q.isEmpty());
362	}
363
364	/**
365	* containsAll returns false unless empty
366	*/
367	public void testContainsAll() { testContainsAll(false); }
368	public void testContainsAll_fair() { testContainsAll(true); }
369	public void testContainsAll(boolean fair) {
370	final SynchronousQueue q = new SynchronousQueue(fair);
371	Integer[] empty = new Integer[0];
372	assertTrue(q.containsAll(Arrays.asList(empty)));
373	Integer[] ints = new Integer[1]; ints[0] = zero;
374	assertFalse(q.containsAll(Arrays.asList(ints)));
375	}
376
377	/**
378	* retainAll returns false
379	*/
380	public void testRetainAll() { testRetainAll(false); }
381	public void testRetainAll_fair() { testRetainAll(true); }
382	public void testRetainAll(boolean fair) {
383	final SynchronousQueue q = new SynchronousQueue(fair);
384	Integer[] empty = new Integer[0];
385	assertFalse(q.retainAll(Arrays.asList(empty)));
386	Integer[] ints = new Integer[1]; ints[0] = zero;
387	assertFalse(q.retainAll(Arrays.asList(ints)));
388	}
389
390	/**
391	* removeAll returns false
392	*/
393	public void testRemoveAll() { testRemoveAll(false); }
394	public void testRemoveAll_fair() { testRemoveAll(true); }
395	public void testRemoveAll(boolean fair) {
396	final SynchronousQueue q = new SynchronousQueue(fair);
397	Integer[] empty = new Integer[0];
398	assertFalse(q.removeAll(Arrays.asList(empty)));
399	Integer[] ints = new Integer[1]; ints[0] = zero;
400	assertFalse(q.containsAll(Arrays.asList(ints)));
401	}
402
403	/**
404	* toArray is empty
405	*/
406	public void testToArray() { testToArray(false); }
407	public void testToArray_fair() { testToArray(true); }
408	public void testToArray(boolean fair) {
409	final SynchronousQueue q = new SynchronousQueue(fair);
410	Object[] o = q.toArray();
411	assertEquals(0, o.length);
412	}
413
414	/**
415	* toArray(Integer array) returns its argument with the first
416	* element (if present) nulled out
417	*/
418	public void testToArray2() { testToArray2(false); }
419	public void testToArray2_fair() { testToArray2(true); }
420	public void testToArray2(boolean fair) {
421	final SynchronousQueue<Integer> q = new SynchronousQueue<>(fair);
422	Integer[] a;
423
424	a = new Integer[0];
425	assertSame(a, q.toArray(a));
426
427	a = new Integer[3];
428	Arrays.fill(a, 42);
429	assertSame(a, q.toArray(a));
430	assertNull(a[0]);
431	for (int i = 1; i < a.length; i++)
432	assertEquals(42, (int) a[i]);
433	}
434
435	/**
436	* toArray(null) throws NPE
437	*/
438	public void testToArray_null() { testToArray_null(false); }
439	public void testToArray_null_fair() { testToArray_null(true); }
440	public void testToArray_null(boolean fair) {
441	final SynchronousQueue q = new SynchronousQueue(fair);
442	try {
443	Object[] o = q.toArray((Object[])null);
444	shouldThrow();
445	} catch (NullPointerException success) {}
446	}
447
448	/**
449	* iterator does not traverse any elements
450	*/
451	public void testIterator() { testIterator(false); }
452	public void testIterator_fair() { testIterator(true); }
453	public void testIterator(boolean fair) {
454	assertIteratorExhausted(new SynchronousQueue(fair).iterator());
455	}
456
457	/**
458	* iterator remove throws IllegalStateException
459	*/
460	public void testIteratorRemove() { testIteratorRemove(false); }
461	public void testIteratorRemove_fair() { testIteratorRemove(true); }
462	public void testIteratorRemove(boolean fair) {
463	final SynchronousQueue q = new SynchronousQueue(fair);
464	Iterator it = q.iterator();
465	try {
466	it.remove();
467	shouldThrow();
468	} catch (IllegalStateException success) {}
469	}
470
471	/**
472	* toString returns a non-null string
473	*/
474	public void testToString() { testToString(false); }
475	public void testToString_fair() { testToString(true); }
476	public void testToString(boolean fair) {
477	final SynchronousQueue q = new SynchronousQueue(fair);
478	String s = q.toString();
479	assertNotNull(s);
480	}
481
482	/**
483	* offer transfers elements across Executor tasks
484	*/
485	public void testOfferInExecutor() { testOfferInExecutor(false); }
486	public void testOfferInExecutor_fair() { testOfferInExecutor(true); }
487	public void testOfferInExecutor(boolean fair) {
488	final SynchronousQueue q = new SynchronousQueue(fair);
489	final CheckedBarrier threadsStarted = new CheckedBarrier(2);
490	final ExecutorService executor = Executors.newFixedThreadPool(2);
491	try (PoolCleaner cleaner = cleaner(executor)) {
492
493	executor.execute(new CheckedRunnable() {
494	public void realRun() throws InterruptedException {
495	assertFalse(q.offer(one));
496	threadsStarted.await();
497	assertTrue(q.offer(one, LONG_DELAY_MS, MILLISECONDS));
498	assertEquals(0, q.remainingCapacity());
499	}});
500
501	executor.execute(new CheckedRunnable() {
502	public void realRun() throws InterruptedException {
503	threadsStarted.await();
504	assertSame(one, q.take());
505	}});
506	}
507	}
508
509	/**
510	* timed poll retrieves elements across Executor threads
511	*/
512	public void testPollInExecutor() { testPollInExecutor(false); }
513	public void testPollInExecutor_fair() { testPollInExecutor(true); }
514	public void testPollInExecutor(boolean fair) {
515	final SynchronousQueue q = new SynchronousQueue(fair);
516	final CheckedBarrier threadsStarted = new CheckedBarrier(2);
517	final ExecutorService executor = Executors.newFixedThreadPool(2);
518	try (PoolCleaner cleaner = cleaner(executor)) {
519	executor.execute(new CheckedRunnable() {
520	public void realRun() throws InterruptedException {
521	assertNull(q.poll());
522	threadsStarted.await();
523	assertSame(one, q.poll(LONG_DELAY_MS, MILLISECONDS));
524	assertTrue(q.isEmpty());
525	}});
526
527	executor.execute(new CheckedRunnable() {
528	public void realRun() throws InterruptedException {
529	threadsStarted.await();
530	q.put(one);
531	}});
532	}
533	}
534
535	/**
536	* a deserialized/reserialized queue is usable
537	*/
538	public void testSerialization() {
539	final SynchronousQueue x = new SynchronousQueue();
540	final SynchronousQueue y = new SynchronousQueue(false);
541	final SynchronousQueue z = new SynchronousQueue(true);
542	assertSerialEquals(x, y);
543	assertNotSerialEquals(x, z);
544	SynchronousQueue[] qs = { x, y, z };
545	for (SynchronousQueue q : qs) {
546	SynchronousQueue clone = serialClone(q);
547	assertNotSame(q, clone);
548	assertSerialEquals(q, clone);
549	assertTrue(clone.isEmpty());
550	assertEquals(0, clone.size());
551	assertEquals(0, clone.remainingCapacity());
552	assertFalse(clone.offer(zero));
553	}
554	}
555
556	/**
557	* drainTo(c) of empty queue doesn't transfer elements
558	*/
559	public void testDrainTo() { testDrainTo(false); }
560	public void testDrainTo_fair() { testDrainTo(true); }
561	public void testDrainTo(boolean fair) {
562	final SynchronousQueue q = new SynchronousQueue(fair);
563	ArrayList l = new ArrayList();
564	q.drainTo(l);
565	assertEquals(0, q.size());
566	assertEquals(0, l.size());
567	}
568
569	/**
570	* drainTo empties queue, unblocking a waiting put.
571	*/
572	public void testDrainToWithActivePut() { testDrainToWithActivePut(false); }
573	public void testDrainToWithActivePut_fair() { testDrainToWithActivePut(true); }
574	public void testDrainToWithActivePut(boolean fair) {
575	final SynchronousQueue q = new SynchronousQueue(fair);
576	Thread t = newStartedThread(new CheckedRunnable() {
577	public void realRun() throws InterruptedException {
578	q.put(one);
579	}});
580
581	ArrayList l = new ArrayList();
582	long startTime = System.nanoTime();
583	while (l.isEmpty()) {
584	q.drainTo(l);
585	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
586	fail("timed out");
587	Thread.yield();
588	}
589	assertEquals(1, l.size());
590	assertSame(one, l.get(0));
591	awaitTermination(t);
592	}
593
594	/**
595	* drainTo(c, n) empties up to n elements of queue into c
596	*/
597	public void testDrainToN() throws InterruptedException {
598	final SynchronousQueue q = new SynchronousQueue();
599	Thread t1 = newStartedThread(new CheckedRunnable() {
600	public void realRun() throws InterruptedException {
601	q.put(one);
602	}});
603
604	Thread t2 = newStartedThread(new CheckedRunnable() {
605	public void realRun() throws InterruptedException {
606	q.put(two);
607	}});
608
609	ArrayList l = new ArrayList();
610	int drained;
611	while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
612	assertEquals(1, drained);
613	assertEquals(1, l.size());
614	while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
615	assertEquals(1, drained);
616	assertEquals(2, l.size());
617	assertTrue(l.contains(one));
618	assertTrue(l.contains(two));
619	awaitTermination(t1);
620	awaitTermination(t2);
621	}
622
623	/**
624	* remove(null), contains(null) always return false
625	*/
626	public void testNeverContainsNull() {
627	Collection<?> q = new SynchronousQueue();
628	assertFalse(q.contains(null));
629	assertFalse(q.remove(null));
630	}
631
632	}