test/tck/CyclicBarrierTest.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.concurrent.BrokenBarrierException;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;

import junit.framework.Test;
import junit.framework.TestSuite;

public class CyclicBarrierTest extends JSR166TestCase {
    public static void main(String[] args) {
        main(suite(), args);
    }
    public static Test suite() {
        return new TestSuite(CyclicBarrierTest.class);
    }

    /**
     * Spin-waits till the number of waiters == numberOfWaiters.
     */
    void awaitNumberWaiting(CyclicBarrier barrier, int numberOfWaiters) {
        long startTime = System.nanoTime();
        while (barrier.getNumberWaiting() != numberOfWaiters) {
            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
                fail("timed out");
            Thread.yield();
        }
    }

    /**
     * Creating with negative parties throws IllegalArgumentException
     */
    public void testConstructor1() {
        try {
            new CyclicBarrier(-1, (Runnable)null);
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

    /**
     * Creating with negative parties and no action throws
     * IllegalArgumentException
     */
    public void testConstructor2() {
        try {
            new CyclicBarrier(-1);
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

    /**
     * getParties returns the number of parties given in constructor
     */
    public void testGetParties() {
        CyclicBarrier b = new CyclicBarrier(2);
        assertEquals(2, b.getParties());
        assertEquals(0, b.getNumberWaiting());
    }

    /**
     * A 1-party barrier triggers after single await
     */
    public void testSingleParty() throws Exception {
        CyclicBarrier b = new CyclicBarrier(1);
        assertEquals(1, b.getParties());
        assertEquals(0, b.getNumberWaiting());
        b.await();
        b.await();
        assertEquals(0, b.getNumberWaiting());
    }

    /**
     * The supplied barrier action is run at barrier
     */
    public void testBarrierAction() throws Exception {
        final AtomicInteger count = new AtomicInteger(0);
        final Runnable incCount = new Runnable() { public void run() {
            count.getAndIncrement(); }};
        CyclicBarrier b = new CyclicBarrier(1, incCount);
        assertEquals(1, b.getParties());
        assertEquals(0, b.getNumberWaiting());
        b.await();
        b.await();
        assertEquals(0, b.getNumberWaiting());
        assertEquals(2, count.get());
    }

    /**
     * A 2-party/thread barrier triggers after both threads invoke await
     */
    public void testTwoParties() throws Exception {
        final CyclicBarrier b = new CyclicBarrier(2);
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() throws Exception {
                b.await();
                b.await();
                b.await();
                b.await();
            }});

        b.await();
        b.await();
        b.await();
        b.await();
        awaitTermination(t);
    }

    /**
     * An interruption in one party causes others waiting in await to
     * throw BrokenBarrierException
     */
    public void testAwait1_Interrupted_BrokenBarrier() {
        final CyclicBarrier c = new CyclicBarrier(3);
        final CountDownLatch pleaseInterrupt = new CountDownLatch(2);
        Thread t1 = new ThreadShouldThrow(InterruptedException.class) {
            public void realRun() throws Exception {
                pleaseInterrupt.countDown();
                c.await();
            }};
        Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
            public void realRun() throws Exception {
                pleaseInterrupt.countDown();
                c.await();
            }};

        t1.start();
        t2.start();
        await(pleaseInterrupt);
        t1.interrupt();
        awaitTermination(t1);
        awaitTermination(t2);
    }

    /**
     * An interruption in one party causes others waiting in timed await to
     * throw BrokenBarrierException
     */
    public void testAwait2_Interrupted_BrokenBarrier() throws Exception {
        final CyclicBarrier c = new CyclicBarrier(3);
        final CountDownLatch pleaseInterrupt = new CountDownLatch(2);
        Thread t1 = new ThreadShouldThrow(InterruptedException.class) {
            public void realRun() throws Exception {
                pleaseInterrupt.countDown();
                c.await(LONG_DELAY_MS, MILLISECONDS);
            }};
        Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
            public void realRun() throws Exception {
                pleaseInterrupt.countDown();
                c.await(LONG_DELAY_MS, MILLISECONDS);
            }};

        t1.start();
        t2.start();
        await(pleaseInterrupt);
        t1.interrupt();
        awaitTermination(t1);
        awaitTermination(t2);
    }

    /**
     * A timeout in timed await throws TimeoutException
     */
    public void testAwait3_TimeoutException() throws InterruptedException {
        final CyclicBarrier c = new CyclicBarrier(2);
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() throws Exception {
                long startTime = System.nanoTime();
                try {
                    c.await(timeoutMillis(), MILLISECONDS);
                    shouldThrow();
                } catch (TimeoutException success) {}
                assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
            }});

        awaitTermination(t);
    }

    /**
     * A timeout in one party causes others waiting in timed await to
     * throw BrokenBarrierException
     */
    public void testAwait4_Timeout_BrokenBarrier() throws InterruptedException {
        final CyclicBarrier c = new CyclicBarrier(3);
        Thread t1 = newStartedThread(new CheckedRunnable() {
            public void realRun() throws Exception {
                try {
                    c.await(LONG_DELAY_MS, MILLISECONDS);
                    shouldThrow();
                } catch (BrokenBarrierException success) {}
            }});
        Thread t2 = newStartedThread(new CheckedRunnable() {
            public void realRun() throws Exception {
                awaitNumberWaiting(c, 1);
                long startTime = System.nanoTime();
                try {
                    c.await(timeoutMillis(), MILLISECONDS);
                    shouldThrow();
                } catch (TimeoutException success) {}
                assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
            }});

        awaitTermination(t1);
        awaitTermination(t2);
    }

    /**
     * A timeout in one party causes others waiting in await to
     * throw BrokenBarrierException
     */
    public void testAwait5_Timeout_BrokenBarrier() throws InterruptedException {
        final CyclicBarrier c = new CyclicBarrier(3);
        Thread t1 = newStartedThread(new CheckedRunnable() {
            public void realRun() throws Exception {
                try {
                    c.await();
                    shouldThrow();
                } catch (BrokenBarrierException success) {}
            }});
        Thread t2 = newStartedThread(new CheckedRunnable() {
            public void realRun() throws Exception {
                awaitNumberWaiting(c, 1);
                long startTime = System.nanoTime();
                try {
                    c.await(timeoutMillis(), MILLISECONDS);
                    shouldThrow();
                } catch (TimeoutException success) {}
                assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
            }});

        awaitTermination(t1);
        awaitTermination(t2);
    }

    /**
     * A reset of an active barrier causes waiting threads to throw
     * BrokenBarrierException
     */
    public void testReset_BrokenBarrier() throws InterruptedException {
        final CyclicBarrier c = new CyclicBarrier(3);
        final CountDownLatch pleaseReset = new CountDownLatch(2);
        Thread t1 = new ThreadShouldThrow(BrokenBarrierException.class) {
            public void realRun() throws Exception {
                pleaseReset.countDown();
                c.await();
            }};
        Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
            public void realRun() throws Exception {
                pleaseReset.countDown();
                c.await();
            }};

        t1.start();
        t2.start();
        await(pleaseReset);

        awaitNumberWaiting(c, 2);
        c.reset();
        awaitTermination(t1);
        awaitTermination(t2);
    }

    /**
     * A reset before threads enter barrier does not throw
     * BrokenBarrierException
     */
    public void testReset_NoBrokenBarrier() throws Exception {
        final CyclicBarrier c = new CyclicBarrier(3);
        c.reset();

        Thread t1 = newStartedThread(new CheckedRunnable() {
            public void realRun() throws Exception {
                c.await();
            }});
        Thread t2 = newStartedThread(new CheckedRunnable() {
            public void realRun() throws Exception {
                c.await();
            }});

        c.await();
        awaitTermination(t1);
        awaitTermination(t2);
    }

    /**
     * All threads block while a barrier is broken.
     */
    public void testReset_Leakage() throws InterruptedException {
        final CyclicBarrier c = new CyclicBarrier(2);
        final AtomicBoolean done = new AtomicBoolean();
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() {
                while (!done.get()) {
                    try {
                        while (c.isBroken())
                            c.reset();

                        c.await();
                        shouldThrow();
                    }
                    catch (BrokenBarrierException | InterruptedException ok) {}
                }}});

        for (int i = 0; i < 4; i++) {
            delay(timeoutMillis());
            t.interrupt();
        }
        done.set(true);
        t.interrupt();
        awaitTermination(t);
    }

    /**
     * Reset of a non-broken barrier does not break barrier
     */
    public void testResetWithoutBreakage() throws Exception {
        final CyclicBarrier barrier = new CyclicBarrier(3);
        for (int i = 0; i < 3; i++) {
            final CyclicBarrier start = new CyclicBarrier(3);
            Thread t1 = newStartedThread(new CheckedRunnable() {
                public void realRun() throws Exception {
                    start.await();
                    barrier.await();
                }});

            Thread t2 = newStartedThread(new CheckedRunnable() {
                public void realRun() throws Exception {
                    start.await();
                    barrier.await();
                }});

            start.await();
            barrier.await();
            awaitTermination(t1);
            awaitTermination(t2);
            assertFalse(barrier.isBroken());
            assertEquals(0, barrier.getNumberWaiting());
            if (i == 1) barrier.reset();
            assertFalse(barrier.isBroken());
            assertEquals(0, barrier.getNumberWaiting());
        }
    }

    /**
     * Reset of a barrier after interruption reinitializes it.
     */
    public void testResetAfterInterrupt() throws Exception {
        final CyclicBarrier barrier = new CyclicBarrier(3);
        for (int i = 0; i < 2; i++) {
            final CyclicBarrier start = new CyclicBarrier(3);
            Thread t1 = new ThreadShouldThrow(InterruptedException.class) {
                public void realRun() throws Exception {
                    start.await();
                    barrier.await();
                }};

            Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
                public void realRun() throws Exception {
                    start.await();
                    barrier.await();
                }};

            t1.start();
            t2.start();
            start.await();
            t1.interrupt();
            awaitTermination(t1);
            awaitTermination(t2);
            assertTrue(barrier.isBroken());
            assertEquals(0, barrier.getNumberWaiting());
            barrier.reset();
            assertFalse(barrier.isBroken());
            assertEquals(0, barrier.getNumberWaiting());
        }
    }

    /**
     * Reset of a barrier after timeout reinitializes it.
     */
    public void testResetAfterTimeout() throws Exception {
        final CyclicBarrier barrier = new CyclicBarrier(3);
        for (int i = 0; i < 2; i++) {
            assertEquals(0, barrier.getNumberWaiting());
            Thread t1 = newStartedThread(new CheckedRunnable() {
                public void realRun() throws Exception {
                    try {
                        barrier.await();
                        shouldThrow();
                    } catch (BrokenBarrierException success) {}
                }});
            Thread t2 = newStartedThread(new CheckedRunnable() {
                public void realRun() throws Exception {
                    awaitNumberWaiting(barrier, 1);
                    long startTime = System.nanoTime();
                    try {
                        barrier.await(timeoutMillis(), MILLISECONDS);
                        shouldThrow();
                    } catch (TimeoutException success) {}
                    assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
                }});

            awaitTermination(t1);
            awaitTermination(t2);
            assertEquals(0, barrier.getNumberWaiting());
            assertTrue(barrier.isBroken());
            assertEquals(0, barrier.getNumberWaiting());
            barrier.reset();
            assertFalse(barrier.isBroken());
            assertEquals(0, barrier.getNumberWaiting());
        }
    }

    /**
     * Reset of a barrier after a failed command reinitializes it.
     */
    public void testResetAfterCommandException() throws Exception {
        final CyclicBarrier barrier =
            new CyclicBarrier(3, new Runnable() {
                    public void run() {
                        throw new NullPointerException(); }});
        for (int i = 0; i < 2; i++) {
            final CyclicBarrier start = new CyclicBarrier(3);
            Thread t1 = new ThreadShouldThrow(BrokenBarrierException.class) {
                public void realRun() throws Exception {
                    start.await();
                    barrier.await();
                }};

            Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
                public void realRun() throws Exception {
                    start.await();
                    barrier.await();
                }};

            t1.start();
            t2.start();
            start.await();
            awaitNumberWaiting(barrier, 2);
            try {
                barrier.await();
                shouldThrow();
            } catch (NullPointerException success) {}
            awaitTermination(t1);
            awaitTermination(t2);
            assertTrue(barrier.isBroken());
            assertEquals(0, barrier.getNumberWaiting());
            barrier.reset();
            assertFalse(barrier.isBroken());
            assertEquals(0, barrier.getNumberWaiting());
        }
    }

    /**
     * There can be more threads calling await() than parties, as long as each
     * task only calls await once and the task count is a multiple of parties.
     */
    public void testMoreTasksThanParties() throws Exception {
        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
        final int parties = rnd.nextInt(1, 5);
        final int nTasks = rnd.nextInt(1, 5) * parties;
        final AtomicInteger tripCount = new AtomicInteger(0);
        final AtomicInteger awaitCount = new AtomicInteger(0);
        final CyclicBarrier barrier =
            new CyclicBarrier(parties, () -> tripCount.getAndIncrement());
        final ExecutorService e = Executors.newFixedThreadPool(nTasks);
        final Runnable awaiter = () -> {
            try {
                if (randomBoolean())
                    barrier.await();
                else
                    barrier.await(LONG_DELAY_MS, MILLISECONDS);
                awaitCount.getAndIncrement();
            } catch (Throwable fail) { threadUnexpectedException(fail); }};
        try (PoolCleaner cleaner = cleaner(e)) {
            for (int i = nTasks; i--> 0; )
                e.execute(awaiter);
        }
        assertEquals(nTasks / parties, tripCount.get());
        assertEquals(nTasks, awaitCount.get());
        assertEquals(0, barrier.getNumberWaiting());
    }
}
Revision:	1.32
Committed:	Tue Aug 13 00:54:51 2019 UTC (4 years, 9 months ago) by jsr166
Branch:	MAIN
Changes since 1.31:	+1 -1 lines
Log Message:	use randomBoolean()
#	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.concurrent.BrokenBarrierException;
12	import java.util.concurrent.CountDownLatch;
13	import java.util.concurrent.CyclicBarrier;
14	import java.util.concurrent.ExecutorService;
15	import java.util.concurrent.Executors;
16	import java.util.concurrent.ThreadLocalRandom;
17	import java.util.concurrent.TimeoutException;
18	import java.util.concurrent.atomic.AtomicBoolean;
19	import java.util.concurrent.atomic.AtomicInteger;
20
21	import junit.framework.Test;
22	import junit.framework.TestSuite;
23
24	public class CyclicBarrierTest extends JSR166TestCase {
25	public static void main(String[] args) {
26	main(suite(), args);
27	}
28	public static Test suite() {
29	return new TestSuite(CyclicBarrierTest.class);
30	}
31
32	/**
33	* Spin-waits till the number of waiters == numberOfWaiters.
34	*/
35	void awaitNumberWaiting(CyclicBarrier barrier, int numberOfWaiters) {
36	long startTime = System.nanoTime();
37	while (barrier.getNumberWaiting() != numberOfWaiters) {
38	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
39	fail("timed out");
40	Thread.yield();
41	}
42	}
43
44	/**
45	* Creating with negative parties throws IllegalArgumentException
46	*/
47	public void testConstructor1() {
48	try {
49	new CyclicBarrier(-1, (Runnable)null);
50	shouldThrow();
51	} catch (IllegalArgumentException success) {}
52	}
53
54	/**
55	* Creating with negative parties and no action throws
56	* IllegalArgumentException
57	*/
58	public void testConstructor2() {
59	try {
60	new CyclicBarrier(-1);
61	shouldThrow();
62	} catch (IllegalArgumentException success) {}
63	}
64
65	/**
66	* getParties returns the number of parties given in constructor
67	*/
68	public void testGetParties() {
69	CyclicBarrier b = new CyclicBarrier(2);
70	assertEquals(2, b.getParties());
71	assertEquals(0, b.getNumberWaiting());
72	}
73
74	/**
75	* A 1-party barrier triggers after single await
76	*/
77	public void testSingleParty() throws Exception {
78	CyclicBarrier b = new CyclicBarrier(1);
79	assertEquals(1, b.getParties());
80	assertEquals(0, b.getNumberWaiting());
81	b.await();
82	b.await();
83	assertEquals(0, b.getNumberWaiting());
84	}
85
86	/**
87	* The supplied barrier action is run at barrier
88	*/
89	public void testBarrierAction() throws Exception {
90	final AtomicInteger count = new AtomicInteger(0);
91	final Runnable incCount = new Runnable() { public void run() {
92	count.getAndIncrement(); }};
93	CyclicBarrier b = new CyclicBarrier(1, incCount);
94	assertEquals(1, b.getParties());
95	assertEquals(0, b.getNumberWaiting());
96	b.await();
97	b.await();
98	assertEquals(0, b.getNumberWaiting());
99	assertEquals(2, count.get());
100	}
101
102	/**
103	* A 2-party/thread barrier triggers after both threads invoke await
104	*/
105	public void testTwoParties() throws Exception {
106	final CyclicBarrier b = new CyclicBarrier(2);
107	Thread t = newStartedThread(new CheckedRunnable() {
108	public void realRun() throws Exception {
109	b.await();
110	b.await();
111	b.await();
112	b.await();
113	}});
114
115	b.await();
116	b.await();
117	b.await();
118	b.await();
119	awaitTermination(t);
120	}
121
122	/**
123	* An interruption in one party causes others waiting in await to
124	* throw BrokenBarrierException
125	*/
126	public void testAwait1_Interrupted_BrokenBarrier() {
127	final CyclicBarrier c = new CyclicBarrier(3);
128	final CountDownLatch pleaseInterrupt = new CountDownLatch(2);
129	Thread t1 = new ThreadShouldThrow(InterruptedException.class) {
130	public void realRun() throws Exception {
131	pleaseInterrupt.countDown();
132	c.await();
133	}};
134	Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
135	public void realRun() throws Exception {
136	pleaseInterrupt.countDown();
137	c.await();
138	}};
139
140	t1.start();
141	t2.start();
142	await(pleaseInterrupt);
143	t1.interrupt();
144	awaitTermination(t1);
145	awaitTermination(t2);
146	}
147
148	/**
149	* An interruption in one party causes others waiting in timed await to
150	* throw BrokenBarrierException
151	*/
152	public void testAwait2_Interrupted_BrokenBarrier() throws Exception {
153	final CyclicBarrier c = new CyclicBarrier(3);
154	final CountDownLatch pleaseInterrupt = new CountDownLatch(2);
155	Thread t1 = new ThreadShouldThrow(InterruptedException.class) {
156	public void realRun() throws Exception {
157	pleaseInterrupt.countDown();
158	c.await(LONG_DELAY_MS, MILLISECONDS);
159	}};
160	Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
161	public void realRun() throws Exception {
162	pleaseInterrupt.countDown();
163	c.await(LONG_DELAY_MS, MILLISECONDS);
164	}};
165
166	t1.start();
167	t2.start();
168	await(pleaseInterrupt);
169	t1.interrupt();
170	awaitTermination(t1);
171	awaitTermination(t2);
172	}
173
174	/**
175	* A timeout in timed await throws TimeoutException
176	*/
177	public void testAwait3_TimeoutException() throws InterruptedException {
178	final CyclicBarrier c = new CyclicBarrier(2);
179	Thread t = newStartedThread(new CheckedRunnable() {
180	public void realRun() throws Exception {
181	long startTime = System.nanoTime();
182	try {
183	c.await(timeoutMillis(), MILLISECONDS);
184	shouldThrow();
185	} catch (TimeoutException success) {}
186	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
187	}});
188
189	awaitTermination(t);
190	}
191
192	/**
193	* A timeout in one party causes others waiting in timed await to
194	* throw BrokenBarrierException
195	*/
196	public void testAwait4_Timeout_BrokenBarrier() throws InterruptedException {
197	final CyclicBarrier c = new CyclicBarrier(3);
198	Thread t1 = newStartedThread(new CheckedRunnable() {
199	public void realRun() throws Exception {
200	try {
201	c.await(LONG_DELAY_MS, MILLISECONDS);
202	shouldThrow();
203	} catch (BrokenBarrierException success) {}
204	}});
205	Thread t2 = newStartedThread(new CheckedRunnable() {
206	public void realRun() throws Exception {
207	awaitNumberWaiting(c, 1);
208	long startTime = System.nanoTime();
209	try {
210	c.await(timeoutMillis(), MILLISECONDS);
211	shouldThrow();
212	} catch (TimeoutException success) {}
213	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
214	}});
215
216	awaitTermination(t1);
217	awaitTermination(t2);
218	}
219
220	/**
221	* A timeout in one party causes others waiting in await to
222	* throw BrokenBarrierException
223	*/
224	public void testAwait5_Timeout_BrokenBarrier() throws InterruptedException {
225	final CyclicBarrier c = new CyclicBarrier(3);
226	Thread t1 = newStartedThread(new CheckedRunnable() {
227	public void realRun() throws Exception {
228	try {
229	c.await();
230	shouldThrow();
231	} catch (BrokenBarrierException success) {}
232	}});
233	Thread t2 = newStartedThread(new CheckedRunnable() {
234	public void realRun() throws Exception {
235	awaitNumberWaiting(c, 1);
236	long startTime = System.nanoTime();
237	try {
238	c.await(timeoutMillis(), MILLISECONDS);
239	shouldThrow();
240	} catch (TimeoutException success) {}
241	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
242	}});
243
244	awaitTermination(t1);
245	awaitTermination(t2);
246	}
247
248	/**
249	* A reset of an active barrier causes waiting threads to throw
250	* BrokenBarrierException
251	*/
252	public void testReset_BrokenBarrier() throws InterruptedException {
253	final CyclicBarrier c = new CyclicBarrier(3);
254	final CountDownLatch pleaseReset = new CountDownLatch(2);
255	Thread t1 = new ThreadShouldThrow(BrokenBarrierException.class) {
256	public void realRun() throws Exception {
257	pleaseReset.countDown();
258	c.await();
259	}};
260	Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
261	public void realRun() throws Exception {
262	pleaseReset.countDown();
263	c.await();
264	}};
265
266	t1.start();
267	t2.start();
268	await(pleaseReset);
269
270	awaitNumberWaiting(c, 2);
271	c.reset();
272	awaitTermination(t1);
273	awaitTermination(t2);
274	}
275
276	/**
277	* A reset before threads enter barrier does not throw
278	* BrokenBarrierException
279	*/
280	public void testReset_NoBrokenBarrier() throws Exception {
281	final CyclicBarrier c = new CyclicBarrier(3);
282	c.reset();
283
284	Thread t1 = newStartedThread(new CheckedRunnable() {
285	public void realRun() throws Exception {
286	c.await();
287	}});
288	Thread t2 = newStartedThread(new CheckedRunnable() {
289	public void realRun() throws Exception {
290	c.await();
291	}});
292
293	c.await();
294	awaitTermination(t1);
295	awaitTermination(t2);
296	}
297
298	/**
299	* All threads block while a barrier is broken.
300	*/
301	public void testReset_Leakage() throws InterruptedException {
302	final CyclicBarrier c = new CyclicBarrier(2);
303	final AtomicBoolean done = new AtomicBoolean();
304	Thread t = newStartedThread(new CheckedRunnable() {
305	public void realRun() {
306	while (!done.get()) {
307	try {
308	while (c.isBroken())
309	c.reset();
310
311	c.await();
312	shouldThrow();
313	}
314	catch (BrokenBarrierException \| InterruptedException ok) {}
315	}}});
316
317	for (int i = 0; i < 4; i++) {
318	delay(timeoutMillis());
319	t.interrupt();
320	}
321	done.set(true);
322	t.interrupt();
323	awaitTermination(t);
324	}
325
326	/**
327	* Reset of a non-broken barrier does not break barrier
328	*/
329	public void testResetWithoutBreakage() throws Exception {
330	final CyclicBarrier barrier = new CyclicBarrier(3);
331	for (int i = 0; i < 3; i++) {
332	final CyclicBarrier start = new CyclicBarrier(3);
333	Thread t1 = newStartedThread(new CheckedRunnable() {
334	public void realRun() throws Exception {
335	start.await();
336	barrier.await();
337	}});
338
339	Thread t2 = newStartedThread(new CheckedRunnable() {
340	public void realRun() throws Exception {
341	start.await();
342	barrier.await();
343	}});
344
345	start.await();
346	barrier.await();
347	awaitTermination(t1);
348	awaitTermination(t2);
349	assertFalse(barrier.isBroken());
350	assertEquals(0, barrier.getNumberWaiting());
351	if (i == 1) barrier.reset();
352	assertFalse(barrier.isBroken());
353	assertEquals(0, barrier.getNumberWaiting());
354	}
355	}
356
357	/**
358	* Reset of a barrier after interruption reinitializes it.
359	*/
360	public void testResetAfterInterrupt() throws Exception {
361	final CyclicBarrier barrier = new CyclicBarrier(3);
362	for (int i = 0; i < 2; i++) {
363	final CyclicBarrier start = new CyclicBarrier(3);
364	Thread t1 = new ThreadShouldThrow(InterruptedException.class) {
365	public void realRun() throws Exception {
366	start.await();
367	barrier.await();
368	}};
369
370	Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
371	public void realRun() throws Exception {
372	start.await();
373	barrier.await();
374	}};
375
376	t1.start();
377	t2.start();
378	start.await();
379	t1.interrupt();
380	awaitTermination(t1);
381	awaitTermination(t2);
382	assertTrue(barrier.isBroken());
383	assertEquals(0, barrier.getNumberWaiting());
384	barrier.reset();
385	assertFalse(barrier.isBroken());
386	assertEquals(0, barrier.getNumberWaiting());
387	}
388	}
389
390	/**
391	* Reset of a barrier after timeout reinitializes it.
392	*/
393	public void testResetAfterTimeout() throws Exception {
394	final CyclicBarrier barrier = new CyclicBarrier(3);
395	for (int i = 0; i < 2; i++) {
396	assertEquals(0, barrier.getNumberWaiting());
397	Thread t1 = newStartedThread(new CheckedRunnable() {
398	public void realRun() throws Exception {
399	try {
400	barrier.await();
401	shouldThrow();
402	} catch (BrokenBarrierException success) {}
403	}});
404	Thread t2 = newStartedThread(new CheckedRunnable() {
405	public void realRun() throws Exception {
406	awaitNumberWaiting(barrier, 1);
407	long startTime = System.nanoTime();
408	try {
409	barrier.await(timeoutMillis(), MILLISECONDS);
410	shouldThrow();
411	} catch (TimeoutException success) {}
412	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
413	}});
414
415	awaitTermination(t1);
416	awaitTermination(t2);
417	assertEquals(0, barrier.getNumberWaiting());
418	assertTrue(barrier.isBroken());
419	assertEquals(0, barrier.getNumberWaiting());
420	barrier.reset();
421	assertFalse(barrier.isBroken());
422	assertEquals(0, barrier.getNumberWaiting());
423	}
424	}
425
426	/**
427	* Reset of a barrier after a failed command reinitializes it.
428	*/
429	public void testResetAfterCommandException() throws Exception {
430	final CyclicBarrier barrier =
431	new CyclicBarrier(3, new Runnable() {
432	public void run() {
433	throw new NullPointerException(); }});
434	for (int i = 0; i < 2; i++) {
435	final CyclicBarrier start = new CyclicBarrier(3);
436	Thread t1 = new ThreadShouldThrow(BrokenBarrierException.class) {
437	public void realRun() throws Exception {
438	start.await();
439	barrier.await();
440	}};
441
442	Thread t2 = new ThreadShouldThrow(BrokenBarrierException.class) {
443	public void realRun() throws Exception {
444	start.await();
445	barrier.await();
446	}};
447
448	t1.start();
449	t2.start();
450	start.await();
451	awaitNumberWaiting(barrier, 2);
452	try {
453	barrier.await();
454	shouldThrow();
455	} catch (NullPointerException success) {}
456	awaitTermination(t1);
457	awaitTermination(t2);
458	assertTrue(barrier.isBroken());
459	assertEquals(0, barrier.getNumberWaiting());
460	barrier.reset();
461	assertFalse(barrier.isBroken());
462	assertEquals(0, barrier.getNumberWaiting());
463	}
464	}
465
466	/**
467	* There can be more threads calling await() than parties, as long as each
468	* task only calls await once and the task count is a multiple of parties.
469	*/
470	public void testMoreTasksThanParties() throws Exception {
471	final ThreadLocalRandom rnd = ThreadLocalRandom.current();
472	final int parties = rnd.nextInt(1, 5);
473	final int nTasks = rnd.nextInt(1, 5) * parties;
474	final AtomicInteger tripCount = new AtomicInteger(0);
475	final AtomicInteger awaitCount = new AtomicInteger(0);
476	final CyclicBarrier barrier =
477	new CyclicBarrier(parties, () -> tripCount.getAndIncrement());
478	final ExecutorService e = Executors.newFixedThreadPool(nTasks);
479	final Runnable awaiter = () -> {
480	try {
481	if (randomBoolean())
482	barrier.await();
483	else
484	barrier.await(LONG_DELAY_MS, MILLISECONDS);
485	awaitCount.getAndIncrement();
486	} catch (Throwable fail) { threadUnexpectedException(fail); }};
487	try (PoolCleaner cleaner = cleaner(e)) {
488	for (int i = nTasks; i--> 0; )
489	e.execute(awaiter);
490	}
491	assertEquals(nTasks / parties, tripCount.get());
492	assertEquals(nTasks, awaitCount.get());
493	assertEquals(0, barrier.getNumberWaiting());
494	}
495	}