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);

                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:	1.57
Committed:	Sun May 14 03:48:35 2017 UTC (7 years ago) by jsr166
Branch:	MAIN
Changes since 1.56:	+8 -10 lines
Log Message:	switch to randomized fairness for tests that block
#	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	pleaseInterrupt.countDown();
163	try {
164	q.put(99);
165	shouldThrow();
166	} catch (InterruptedException success) {}
167	assertFalse(Thread.interrupted());
168	}});
169
170	await(pleaseTake);
171	assertEquals(0, q.remainingCapacity());
172	try { assertSame(one, q.take()); }
173	catch (InterruptedException e) { threadUnexpectedException(e); }
174
175	await(pleaseInterrupt);
176	assertThreadBlocks(t, Thread.State.WAITING);
177	t.interrupt();
178	awaitTermination(t);
179	assertEquals(0, q.remainingCapacity());
180	}
181
182	/**
183	* timed offer times out if elements not taken
184	*/
185	public void testTimedOffer() {
186	final boolean fair = ThreadLocalRandom.current().nextBoolean();
187	final SynchronousQueue q = new SynchronousQueue(fair);
188	final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
189	Thread t = newStartedThread(new CheckedRunnable() {
190	public void realRun() throws InterruptedException {
191	long startTime = System.nanoTime();
192	assertFalse(q.offer(new Object(), timeoutMillis(), MILLISECONDS));
193	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
194	pleaseInterrupt.countDown();
195	try {
196	q.offer(new Object(), 2 * LONG_DELAY_MS, MILLISECONDS);
197	shouldThrow();
198	} catch (InterruptedException success) {}
199	assertFalse(Thread.interrupted());
200	}});
201
202	await(pleaseInterrupt);
203	assertThreadBlocks(t, Thread.State.TIMED_WAITING);
204	t.interrupt();
205	awaitTermination(t);
206	}
207
208	/**
209	* poll return null if no active putter
210	*/
211	public void testPoll() { testPoll(false); }
212	public void testPoll_fair() { testPoll(true); }
213	public void testPoll(boolean fair) {
214	final SynchronousQueue q = new SynchronousQueue(fair);
215	assertNull(q.poll());
216	}
217
218	/**
219	* timed poll with zero timeout times out if no active putter
220	*/
221	public void testTimedPoll0() { testTimedPoll0(false); }
222	public void testTimedPoll0_fair() { testTimedPoll0(true); }
223	public void testTimedPoll0(boolean fair) {
224	final SynchronousQueue q = new SynchronousQueue(fair);
225	try { assertNull(q.poll(0, MILLISECONDS)); }
226	catch (InterruptedException e) { threadUnexpectedException(e); }
227	}
228
229	/**
230	* timed poll with nonzero timeout times out if no active putter
231	*/
232	public void testTimedPoll() {
233	final boolean fair = ThreadLocalRandom.current().nextBoolean();
234	final SynchronousQueue q = new SynchronousQueue(fair);
235	final long startTime = System.nanoTime();
236	try { assertNull(q.poll(timeoutMillis(), MILLISECONDS)); }
237	catch (InterruptedException e) { threadUnexpectedException(e); }
238	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
239	}
240
241	/**
242	* timed poll before a delayed offer times out, returning null;
243	* after offer succeeds; on interruption throws
244	*/
245	public void testTimedPollWithOffer() {
246	final boolean fair = ThreadLocalRandom.current().nextBoolean();
247	final SynchronousQueue q = new SynchronousQueue(fair);
248	final CountDownLatch pleaseOffer = new CountDownLatch(1);
249	final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
250	Thread t = newStartedThread(new CheckedRunnable() {
251	public void realRun() throws InterruptedException {
252	long startTime = System.nanoTime();
253	assertNull(q.poll(timeoutMillis(), MILLISECONDS));
254	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
255
256	pleaseOffer.countDown();
257	startTime = System.nanoTime();
258	assertSame(zero, q.poll(LONG_DELAY_MS, MILLISECONDS));
259
260	Thread.currentThread().interrupt();
261	try {
262	q.poll(LONG_DELAY_MS, MILLISECONDS);
263	shouldThrow();
264	} catch (InterruptedException success) {}
265	assertFalse(Thread.interrupted());
266
267	pleaseInterrupt.countDown();
268	try {
269	q.poll(LONG_DELAY_MS, MILLISECONDS);
270	shouldThrow();
271	} catch (InterruptedException success) {}
272	assertFalse(Thread.interrupted());
273
274	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
275	}});
276
277	await(pleaseOffer);
278	long startTime = System.nanoTime();
279	try { assertTrue(q.offer(zero, LONG_DELAY_MS, MILLISECONDS)); }
280	catch (InterruptedException e) { threadUnexpectedException(e); }
281	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
282
283	await(pleaseInterrupt);
284	assertThreadBlocks(t, Thread.State.TIMED_WAITING);
285	t.interrupt();
286	awaitTermination(t);
287	}
288
289	/**
290	* peek() returns null if no active putter
291	*/
292	public void testPeek() { testPeek(false); }
293	public void testPeek_fair() { testPeek(true); }
294	public void testPeek(boolean fair) {
295	final SynchronousQueue q = new SynchronousQueue(fair);
296	assertNull(q.peek());
297	}
298
299	/**
300	* element() throws NoSuchElementException if no active putter
301	*/
302	public void testElement() { testElement(false); }
303	public void testElement_fair() { testElement(true); }
304	public void testElement(boolean fair) {
305	final SynchronousQueue q = new SynchronousQueue(fair);
306	try {
307	q.element();
308	shouldThrow();
309	} catch (NoSuchElementException success) {}
310	}
311
312	/**
313	* remove() throws NoSuchElementException if no active putter
314	*/
315	public void testRemove() { testRemove(false); }
316	public void testRemove_fair() { testRemove(true); }
317	public void testRemove(boolean fair) {
318	final SynchronousQueue q = new SynchronousQueue(fair);
319	try {
320	q.remove();
321	shouldThrow();
322	} catch (NoSuchElementException success) {}
323	}
324
325	/**
326	* contains returns false
327	*/
328	public void testContains() { testContains(false); }
329	public void testContains_fair() { testContains(true); }
330	public void testContains(boolean fair) {
331	final SynchronousQueue q = new SynchronousQueue(fair);
332	assertFalse(q.contains(zero));
333	}
334
335	/**
336	* clear ensures isEmpty
337	*/
338	public void testClear() { testClear(false); }
339	public void testClear_fair() { testClear(true); }
340	public void testClear(boolean fair) {
341	final SynchronousQueue q = new SynchronousQueue(fair);
342	q.clear();
343	assertTrue(q.isEmpty());
344	}
345
346	/**
347	* containsAll returns false unless empty
348	*/
349	public void testContainsAll() { testContainsAll(false); }
350	public void testContainsAll_fair() { testContainsAll(true); }
351	public void testContainsAll(boolean fair) {
352	final SynchronousQueue q = new SynchronousQueue(fair);
353	Integer[] empty = new Integer[0];
354	assertTrue(q.containsAll(Arrays.asList(empty)));
355	Integer[] ints = new Integer[1]; ints[0] = zero;
356	assertFalse(q.containsAll(Arrays.asList(ints)));
357	}
358
359	/**
360	* retainAll returns false
361	*/
362	public void testRetainAll() { testRetainAll(false); }
363	public void testRetainAll_fair() { testRetainAll(true); }
364	public void testRetainAll(boolean fair) {
365	final SynchronousQueue q = new SynchronousQueue(fair);
366	Integer[] empty = new Integer[0];
367	assertFalse(q.retainAll(Arrays.asList(empty)));
368	Integer[] ints = new Integer[1]; ints[0] = zero;
369	assertFalse(q.retainAll(Arrays.asList(ints)));
370	}
371
372	/**
373	* removeAll returns false
374	*/
375	public void testRemoveAll() { testRemoveAll(false); }
376	public void testRemoveAll_fair() { testRemoveAll(true); }
377	public void testRemoveAll(boolean fair) {
378	final SynchronousQueue q = new SynchronousQueue(fair);
379	Integer[] empty = new Integer[0];
380	assertFalse(q.removeAll(Arrays.asList(empty)));
381	Integer[] ints = new Integer[1]; ints[0] = zero;
382	assertFalse(q.containsAll(Arrays.asList(ints)));
383	}
384
385	/**
386	* toArray is empty
387	*/
388	public void testToArray() { testToArray(false); }
389	public void testToArray_fair() { testToArray(true); }
390	public void testToArray(boolean fair) {
391	final SynchronousQueue q = new SynchronousQueue(fair);
392	Object[] o = q.toArray();
393	assertEquals(0, o.length);
394	}
395
396	/**
397	* toArray(Integer array) returns its argument with the first
398	* element (if present) nulled out
399	*/
400	public void testToArray2() { testToArray2(false); }
401	public void testToArray2_fair() { testToArray2(true); }
402	public void testToArray2(boolean fair) {
403	final SynchronousQueue<Integer> q = new SynchronousQueue<>(fair);
404	Integer[] a;
405
406	a = new Integer[0];
407	assertSame(a, q.toArray(a));
408
409	a = new Integer[3];
410	Arrays.fill(a, 42);
411	assertSame(a, q.toArray(a));
412	assertNull(a[0]);
413	for (int i = 1; i < a.length; i++)
414	assertEquals(42, (int) a[i]);
415	}
416
417	/**
418	* toArray(null) throws NPE
419	*/
420	public void testToArray_null() { testToArray_null(false); }
421	public void testToArray_null_fair() { testToArray_null(true); }
422	public void testToArray_null(boolean fair) {
423	final SynchronousQueue q = new SynchronousQueue(fair);
424	try {
425	Object[] o = q.toArray(null);
426	shouldThrow();
427	} catch (NullPointerException success) {}
428	}
429
430	/**
431	* iterator does not traverse any elements
432	*/
433	public void testIterator() { testIterator(false); }
434	public void testIterator_fair() { testIterator(true); }
435	public void testIterator(boolean fair) {
436	assertIteratorExhausted(new SynchronousQueue(fair).iterator());
437	}
438
439	/**
440	* iterator remove throws ISE
441	*/
442	public void testIteratorRemove() { testIteratorRemove(false); }
443	public void testIteratorRemove_fair() { testIteratorRemove(true); }
444	public void testIteratorRemove(boolean fair) {
445	final SynchronousQueue q = new SynchronousQueue(fair);
446	Iterator it = q.iterator();
447	try {
448	it.remove();
449	shouldThrow();
450	} catch (IllegalStateException success) {}
451	}
452
453	/**
454	* toString returns a non-null string
455	*/
456	public void testToString() { testToString(false); }
457	public void testToString_fair() { testToString(true); }
458	public void testToString(boolean fair) {
459	final SynchronousQueue q = new SynchronousQueue(fair);
460	String s = q.toString();
461	assertNotNull(s);
462	}
463
464	/**
465	* offer transfers elements across Executor tasks
466	*/
467	public void testOfferInExecutor() { testOfferInExecutor(false); }
468	public void testOfferInExecutor_fair() { testOfferInExecutor(true); }
469	public void testOfferInExecutor(boolean fair) {
470	final SynchronousQueue q = new SynchronousQueue(fair);
471	final CheckedBarrier threadsStarted = new CheckedBarrier(2);
472	final ExecutorService executor = Executors.newFixedThreadPool(2);
473	try (PoolCleaner cleaner = cleaner(executor)) {
474
475	executor.execute(new CheckedRunnable() {
476	public void realRun() throws InterruptedException {
477	assertFalse(q.offer(one));
478	threadsStarted.await();
479	assertTrue(q.offer(one, LONG_DELAY_MS, MILLISECONDS));
480	assertEquals(0, q.remainingCapacity());
481	}});
482
483	executor.execute(new CheckedRunnable() {
484	public void realRun() throws InterruptedException {
485	threadsStarted.await();
486	assertSame(one, q.take());
487	}});
488	}
489	}
490
491	/**
492	* timed poll retrieves elements across Executor threads
493	*/
494	public void testPollInExecutor() { testPollInExecutor(false); }
495	public void testPollInExecutor_fair() { testPollInExecutor(true); }
496	public void testPollInExecutor(boolean fair) {
497	final SynchronousQueue q = new SynchronousQueue(fair);
498	final CheckedBarrier threadsStarted = new CheckedBarrier(2);
499	final ExecutorService executor = Executors.newFixedThreadPool(2);
500	try (PoolCleaner cleaner = cleaner(executor)) {
501	executor.execute(new CheckedRunnable() {
502	public void realRun() throws InterruptedException {
503	assertNull(q.poll());
504	threadsStarted.await();
505	assertSame(one, q.poll(LONG_DELAY_MS, MILLISECONDS));
506	assertTrue(q.isEmpty());
507	}});
508
509	executor.execute(new CheckedRunnable() {
510	public void realRun() throws InterruptedException {
511	threadsStarted.await();
512	q.put(one);
513	}});
514	}
515	}
516
517	/**
518	* a deserialized serialized queue is usable
519	*/
520	public void testSerialization() {
521	final SynchronousQueue x = new SynchronousQueue();
522	final SynchronousQueue y = new SynchronousQueue(false);
523	final SynchronousQueue z = new SynchronousQueue(true);
524	assertSerialEquals(x, y);
525	assertNotSerialEquals(x, z);
526	SynchronousQueue[] qs = { x, y, z };
527	for (SynchronousQueue q : qs) {
528	SynchronousQueue clone = serialClone(q);
529	assertNotSame(q, clone);
530	assertSerialEquals(q, clone);
531	assertTrue(clone.isEmpty());
532	assertEquals(0, clone.size());
533	assertEquals(0, clone.remainingCapacity());
534	assertFalse(clone.offer(zero));
535	}
536	}
537
538	/**
539	* drainTo(c) of empty queue doesn't transfer elements
540	*/
541	public void testDrainTo() { testDrainTo(false); }
542	public void testDrainTo_fair() { testDrainTo(true); }
543	public void testDrainTo(boolean fair) {
544	final SynchronousQueue q = new SynchronousQueue(fair);
545	ArrayList l = new ArrayList();
546	q.drainTo(l);
547	assertEquals(0, q.size());
548	assertEquals(0, l.size());
549	}
550
551	/**
552	* drainTo empties queue, unblocking a waiting put.
553	*/
554	public void testDrainToWithActivePut() { testDrainToWithActivePut(false); }
555	public void testDrainToWithActivePut_fair() { testDrainToWithActivePut(true); }
556	public void testDrainToWithActivePut(boolean fair) {
557	final SynchronousQueue q = new SynchronousQueue(fair);
558	Thread t = newStartedThread(new CheckedRunnable() {
559	public void realRun() throws InterruptedException {
560	q.put(one);
561	}});
562
563	ArrayList l = new ArrayList();
564	long startTime = System.nanoTime();
565	while (l.isEmpty()) {
566	q.drainTo(l);
567	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
568	fail("timed out");
569	Thread.yield();
570	}
571	assertEquals(1, l.size());
572	assertSame(one, l.get(0));
573	awaitTermination(t);
574	}
575
576	/**
577	* drainTo(c, n) empties up to n elements of queue into c
578	*/
579	public void testDrainToN() throws InterruptedException {
580	final SynchronousQueue q = new SynchronousQueue();
581	Thread t1 = newStartedThread(new CheckedRunnable() {
582	public void realRun() throws InterruptedException {
583	q.put(one);
584	}});
585
586	Thread t2 = newStartedThread(new CheckedRunnable() {
587	public void realRun() throws InterruptedException {
588	q.put(two);
589	}});
590
591	ArrayList l = new ArrayList();
592	int drained;
593	while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
594	assertEquals(1, drained);
595	assertEquals(1, l.size());
596	while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
597	assertEquals(1, drained);
598	assertEquals(2, l.size());
599	assertTrue(l.contains(one));
600	assertTrue(l.contains(two));
601	awaitTermination(t1);
602	awaitTermination(t2);
603	}
604
605	/**
606	* remove(null), contains(null) always return false
607	*/
608	public void testNeverContainsNull() {
609	Collection<?> q = new SynchronousQueue();
610	assertFalse(q.contains(null));
611	assertFalse(q.remove(null));
612	}
613
614	}