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root/jsr166/jsr166/src/test/tck/SemaphoreTest.java

Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.5 by dl, Thu Sep 25 11:02:41 2003 UTC vs.
Revision 1.39 by jsr166, Sun May 14 03:31:53 2017 UTC

#	Line 1 | Line 1
1		/*
2	<	* Written by members of JCP JSR-166 Expert Group and released to the
3	<	* public domain. Use, modify, and redistribute this code in any way
4	<	* without acknowledgement. Other contributors include Andrew Wright,
5	<	* Jeffrey Hayes, Pat Fischer, Mike Judd.
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 junit.framework.*;
10	<	import java.util.*;
11	<	import java.util.concurrent.*;
12	<	import java.io.*;
9	>	import static java.util.concurrent.TimeUnit.MILLISECONDS;
10	>
11	>	import java.util.Collection;
12	>	import java.util.concurrent.CountDownLatch;
13	>	import java.util.concurrent.Semaphore;
14	>	import java.util.concurrent.ThreadLocalRandom;
15	>
16	>	import junit.framework.AssertionFailedError;
17	>	import junit.framework.Test;
18	>	import junit.framework.TestSuite;
19
20		public class SemaphoreTest extends JSR166TestCase {
21		public static void main(String[] args) {
22	<	junit.textui.TestRunner.run (suite());
22	>	main(suite(), args);
23		}
24		public static Test suite() {
25	<	return new TestSuite(SemaphoreTest.class);
25	>	return new TestSuite(SemaphoreTest.class);
26	>	}
27	>
28	>	/**
29	>	* Subclass to expose protected methods
30	>	*/
31	>	static class PublicSemaphore extends Semaphore {
32	>	PublicSemaphore(int permits) { super(permits); }
33	>	PublicSemaphore(int permits, boolean fair) { super(permits, fair); }
34	>	public Collection<Thread> getQueuedThreads() {
35	>	return super.getQueuedThreads();
36	>	}
37	>	public boolean hasQueuedThread(Thread t) {
38	>	return super.getQueuedThreads().contains(t);
39	>	}
40	>	public void reducePermits(int reduction) {
41	>	super.reducePermits(reduction);
42	>	}
43	>	}
44	>
45	>	/**
46	>	* A runnable calling acquire
47	>	*/
48	>	class InterruptibleLockRunnable extends CheckedRunnable {
49	>	final Semaphore lock;
50	>	InterruptibleLockRunnable(Semaphore s) { lock = s; }
51	>	public void realRun() {
52	>	try {
53	>	lock.acquire();
54	>	}
55	>	catch (InterruptedException ignored) {}
56	>	}
57	>	}
58	>
59	>	/**
60	>	* A runnable calling acquire that expects to be interrupted
61	>	*/
62	>	class InterruptedLockRunnable extends CheckedInterruptedRunnable {
63	>	final Semaphore lock;
64	>	InterruptedLockRunnable(Semaphore s) { lock = s; }
65	>	public void realRun() throws InterruptedException {
66	>	lock.acquire();
67	>	}
68	>	}
69	>
70	>	/**
71	>	* Spin-waits until s.hasQueuedThread(t) becomes true.
72	>	*/
73	>	void waitForQueuedThread(PublicSemaphore s, Thread t) {
74	>	long startTime = System.nanoTime();
75	>	while (!s.hasQueuedThread(t)) {
76	>	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
77	>	throw new AssertionFailedError("timed out");
78	>	Thread.yield();
79	>	}
80	>	assertTrue(s.hasQueuedThreads());
81	>	assertTrue(t.isAlive());
82	>	}
83	>
84	>	/**
85	>	* Spin-waits until s.hasQueuedThreads() becomes true.
86	>	*/
87	>	void waitForQueuedThreads(Semaphore s) {
88	>	long startTime = System.nanoTime();
89	>	while (!s.hasQueuedThreads()) {
90	>	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
91	>	throw new AssertionFailedError("timed out");
92	>	Thread.yield();
93	>	}
94	>	}
95	>
96	>	enum AcquireMethod {
97	>	acquire() {
98	>	void acquire(Semaphore s) throws InterruptedException {
99	>	s.acquire();
100	>	}
101	>	},
102	>	acquireN() {
103	>	void acquire(Semaphore s, int permits) throws InterruptedException {
104	>	s.acquire(permits);
105	>	}
106	>	},
107	>	acquireUninterruptibly() {
108	>	void acquire(Semaphore s) {
109	>	s.acquireUninterruptibly();
110	>	}
111	>	},
112	>	acquireUninterruptiblyN() {
113	>	void acquire(Semaphore s, int permits) {
114	>	s.acquireUninterruptibly(permits);
115	>	}
116	>	},
117	>	tryAcquire() {
118	>	void acquire(Semaphore s) {
119	>	assertTrue(s.tryAcquire());
120	>	}
121	>	},
122	>	tryAcquireN() {
123	>	void acquire(Semaphore s, int permits) {
124	>	assertTrue(s.tryAcquire(permits));
125	>	}
126	>	},
127	>	tryAcquireTimed() {
128	>	void acquire(Semaphore s) throws InterruptedException {
129	>	assertTrue(s.tryAcquire(2 * LONG_DELAY_MS, MILLISECONDS));
130	>	}
131	>	Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
132	>	},
133	>	tryAcquireTimedN {
134	>	void acquire(Semaphore s, int permits) throws InterruptedException {
135	>	assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS));
136	>	}
137	>	Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
138	>	};
139	>
140	>	// Intentionally meta-circular
141	>
142	>	/** Acquires 1 permit. */
143	>	void acquire(Semaphore s) throws InterruptedException {
144	>	acquire(s, 1);
145	>	}
146	>	/** Acquires the given number of permits. */
147	>	void acquire(Semaphore s, int permits) throws InterruptedException {
148	>	for (int i = 0; i < permits; i++)
149	>	acquire(s);
150	>	}
151	>	Thread.State parkedState() { return Thread.State.WAITING; }
152		}
153
154		/**
155		* Zero, negative, and positive initial values are allowed in constructor
156		*/
157	<	public void testConstructor() {
158	<	Semaphore s0 = new Semaphore(0);
159	<	assertEquals(0, s0.availablePermits());
160	<	Semaphore s1 = new Semaphore(-1);
161	<	assertEquals(-1, s1.availablePermits());
162	<	Semaphore s2 = new Semaphore(-1);
163	<	assertEquals(-1, s2.availablePermits());
157	>	public void testConstructor()      { testConstructor(false); }
158	>	public void testConstructor_fair() { testConstructor(true); }
159	>	public void testConstructor(boolean fair) {
160	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
161	>	Semaphore s = new Semaphore(permits, fair);
162	>	assertEquals(permits, s.availablePermits());
163	>	assertEquals(fair, s.isFair());
164	>	}
165		}
166
167		/**
168	<	* tryAcquire succeeds when sufficent permits, else fails
168	>	* Constructor without fairness argument behaves as nonfair
169		*/
170	<	public void testTryAcquireInSameThread() {
171	<	Semaphore s = new Semaphore(2);
170	>	public void testConstructorDefaultsToNonFair() {
171	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
172	>	Semaphore s = new Semaphore(permits);
173	>	assertEquals(permits, s.availablePermits());
174	>	assertFalse(s.isFair());
175	>	}
176	>	}
177	>
178	>	/**
179	>	* tryAcquire succeeds when sufficient permits, else fails
180	>	*/
181	>	public void testTryAcquireInSameThread()      { testTryAcquireInSameThread(false); }
182	>	public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); }
183	>	public void testTryAcquireInSameThread(boolean fair) {
184	>	Semaphore s = new Semaphore(2, fair);
185		assertEquals(2, s.availablePermits());
186		assertTrue(s.tryAcquire());
187		assertTrue(s.tryAcquire());
188		assertEquals(0, s.availablePermits());
189		assertFalse(s.tryAcquire());
190	+	assertFalse(s.tryAcquire());
191	+	assertEquals(0, s.availablePermits());
192		}
193
194		/**
195	<	* Acquire and release of semaphore succeed if initially available
195	>	* timed tryAcquire times out
196		*/
197	<	public void testAcquireReleaseInSameThread() {
198	<	Semaphore s = new Semaphore(1);
199	<	try {
200	<	s.acquire();
201	<	s.release();
202	<	s.acquire();
203	<	s.release();
204	<	s.acquire();
205	<	s.release();
206	<	s.acquire();
207	<	s.release();
208	<	s.acquire();
209	<	s.release();
210	<	assertEquals(1, s.availablePermits());
211	<	} catch( InterruptedException e){
212	<	unexpectedException();
197	>	public void testTryAcquire_timeout() {
198	>	final ThreadLocalRandom rnd = ThreadLocalRandom.current();
199	>	final boolean fair = rnd.nextBoolean();
200	>	final Semaphore s = new Semaphore(0, fair);
201	>	final long startTime = System.nanoTime();
202	>	try { assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS)); }
203	>	catch (InterruptedException e) { threadUnexpectedException(e); }
204	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
205	>	}
206	>
207	>	/**
208	>	* timed tryAcquire(N) times out
209	>	*/
210	>	public void testTryAcquireN_timeout() {
211	>	final ThreadLocalRandom rnd = ThreadLocalRandom.current();
212	>	final boolean fair = rnd.nextBoolean();
213	>	final Semaphore s = new Semaphore(2, fair);
214	>	final long startTime = System.nanoTime();
215	>	try { assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS)); }
216	>	catch (InterruptedException e) { threadUnexpectedException(e); }
217	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
218	>	}
219	>
220	>	/**
221	>	* acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
222	>	* are interruptible
223	>	*/
224	>	public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
225	>	public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
226	>	public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
227	>	public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
228	>	public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
229	>	public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
230	>	public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
231	>	public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
232	>	public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
233	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
234	>	final java.util.concurrent.CyclicBarrier pleaseInterrupt
235	>	= new java.util.concurrent.CyclicBarrier(2);
236	>	Thread t = newStartedThread(new CheckedRunnable() {
237	>	public void realRun() {
238	>	// Interrupt before acquire
239	>	Thread.currentThread().interrupt();
240	>	try {
241	>	acquirer.acquire(s);
242	>	shouldThrow();
243	>	} catch (InterruptedException success) {}
244	>	assertFalse(Thread.interrupted());
245	>
246	>	// Interrupt before acquire(N)
247	>	Thread.currentThread().interrupt();
248	>	try {
249	>	acquirer.acquire(s, 3);
250	>	shouldThrow();
251	>	} catch (InterruptedException success) {}
252	>	assertFalse(Thread.interrupted());
253	>
254	>	// Interrupt during acquire
255	>	await(pleaseInterrupt);
256	>	try {
257	>	acquirer.acquire(s);
258	>	shouldThrow();
259	>	} catch (InterruptedException success) {}
260	>	assertFalse(Thread.interrupted());
261	>
262	>	// Interrupt during acquire(N)
263	>	await(pleaseInterrupt);
264	>	try {
265	>	acquirer.acquire(s, 3);
266	>	shouldThrow();
267	>	} catch (InterruptedException success) {}
268	>	assertFalse(Thread.interrupted());
269	>	}});
270	>
271	>	for (int n = 2; n-->0; ) {
272	>	await(pleaseInterrupt);
273	>	assertThreadBlocks(t, acquirer.parkedState());
274	>	t.interrupt();
275		}
276	+
277	+	awaitTermination(t);
278		}
279
280		/**
281	<	* Uninterruptible acquire and release of semaphore succeed if
282	<	* initially available
281	>	* acquireUninterruptibly(), acquireUninterruptibly(N) are
282	>	* uninterruptible
283		*/
284	<	public void testAcquireUninterruptiblyReleaseInSameThread() {
285	<	Semaphore s = new Semaphore(1);
286	<	try {
287	<	s.acquireUninterruptibly();
288	<	s.release();
289	<	s.acquireUninterruptibly();
290	<	s.release();
291	<	s.acquireUninterruptibly();
292	<	s.release();
293	<	s.acquireUninterruptibly();
294	<	s.release();
295	<	s.acquireUninterruptibly();
296	<	s.release();
297	<	assertEquals(1, s.availablePermits());
298	<	} finally {
299	<	}
284	>	public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
285	>	public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
286	>	public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
287	>	public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
288	>	public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
289	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
290	>	final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
291	>
292	>	Thread t1 = newStartedThread(new CheckedRunnable() {
293	>	public void realRun() throws InterruptedException {
294	>	// Interrupt before acquire
295	>	pleaseInterrupt.release();
296	>	Thread.currentThread().interrupt();
297	>	acquirer.acquire(s);
298	>	assertTrue(Thread.interrupted());
299	>	}});
300	>
301	>	Thread t2 = newStartedThread(new CheckedRunnable() {
302	>	public void realRun() throws InterruptedException {
303	>	// Interrupt during acquire
304	>	pleaseInterrupt.release();
305	>	acquirer.acquire(s);
306	>	assertTrue(Thread.interrupted());
307	>	}});
308	>
309	>	await(pleaseInterrupt);
310	>	waitForQueuedThread(s, t1);
311	>	waitForQueuedThread(s, t2);
312	>	t2.interrupt();
313	>
314	>	assertThreadBlocks(t1, Thread.State.WAITING);
315	>	assertThreadBlocks(t2, Thread.State.WAITING);
316	>
317	>	s.release(2);
318	>
319	>	awaitTermination(t1);
320	>	awaitTermination(t2);
321	>	}
322	>
323	>	/**
324	>	* hasQueuedThreads reports whether there are waiting threads
325	>	*/
326	>	public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
327	>	public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
328	>	public void testHasQueuedThreads(boolean fair) {
329	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
330	>	assertFalse(lock.hasQueuedThreads());
331	>	lock.acquireUninterruptibly();
332	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
333	>	waitForQueuedThread(lock, t1);
334	>	assertTrue(lock.hasQueuedThreads());
335	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
336	>	waitForQueuedThread(lock, t2);
337	>	assertTrue(lock.hasQueuedThreads());
338	>	t1.interrupt();
339	>	awaitTermination(t1);
340	>	assertTrue(lock.hasQueuedThreads());
341	>	lock.release();
342	>	awaitTermination(t2);
343	>	assertFalse(lock.hasQueuedThreads());
344	>	}
345	>
346	>	/**
347	>	* getQueueLength reports number of waiting threads
348	>	*/
349	>	public void testGetQueueLength()      { testGetQueueLength(false); }
350	>	public void testGetQueueLength_fair() { testGetQueueLength(true); }
351	>	public void testGetQueueLength(boolean fair) {
352	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
353	>	assertEquals(0, lock.getQueueLength());
354	>	lock.acquireUninterruptibly();
355	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
356	>	waitForQueuedThread(lock, t1);
357	>	assertEquals(1, lock.getQueueLength());
358	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
359	>	waitForQueuedThread(lock, t2);
360	>	assertEquals(2, lock.getQueueLength());
361	>	t1.interrupt();
362	>	awaitTermination(t1);
363	>	assertEquals(1, lock.getQueueLength());
364	>	lock.release();
365	>	awaitTermination(t2);
366	>	assertEquals(0, lock.getQueueLength());
367	>	}
368	>
369	>	/**
370	>	* getQueuedThreads includes waiting threads
371	>	*/
372	>	public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
373	>	public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
374	>	public void testGetQueuedThreads(boolean fair) {
375	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
376	>	assertTrue(lock.getQueuedThreads().isEmpty());
377	>	lock.acquireUninterruptibly();
378	>	assertTrue(lock.getQueuedThreads().isEmpty());
379	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
380	>	waitForQueuedThread(lock, t1);
381	>	assertTrue(lock.getQueuedThreads().contains(t1));
382	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
383	>	waitForQueuedThread(lock, t2);
384	>	assertTrue(lock.getQueuedThreads().contains(t1));
385	>	assertTrue(lock.getQueuedThreads().contains(t2));
386	>	t1.interrupt();
387	>	awaitTermination(t1);
388	>	assertFalse(lock.getQueuedThreads().contains(t1));
389	>	assertTrue(lock.getQueuedThreads().contains(t2));
390	>	lock.release();
391	>	awaitTermination(t2);
392	>	assertTrue(lock.getQueuedThreads().isEmpty());
393	>	}
394	>
395	>	/**
396	>	* drainPermits reports and removes given number of permits
397	>	*/
398	>	public void testDrainPermits()      { testDrainPermits(false); }
399	>	public void testDrainPermits_fair() { testDrainPermits(true); }
400	>	public void testDrainPermits(boolean fair) {
401	>	Semaphore s = new Semaphore(0, fair);
402	>	assertEquals(0, s.availablePermits());
403	>	assertEquals(0, s.drainPermits());
404	>	s.release(10);
405	>	assertEquals(10, s.availablePermits());
406	>	assertEquals(10, s.drainPermits());
407	>	assertEquals(0, s.availablePermits());
408	>	assertEquals(0, s.drainPermits());
409		}
410
411		/**
412	<	* Timed Acquire and release of semaphore succeed if
91	<	* initially available
412	>	* release(-N) throws IllegalArgumentException
413		*/
414	<	public void testTimedAcquireReleaseInSameThread() {
415	<	Semaphore s = new Semaphore(1);
414	>	public void testReleaseIAE()      { testReleaseIAE(false); }
415	>	public void testReleaseIAE_fair() { testReleaseIAE(true); }
416	>	public void testReleaseIAE(boolean fair) {
417	>	Semaphore s = new Semaphore(10, fair);
418		try {
419	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
420	<	s.release();
421	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
99	<	s.release();
100	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
101	<	s.release();
102	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
103	<	s.release();
104	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
105	<	s.release();
106	<	assertEquals(1, s.availablePermits());
107	<	} catch( InterruptedException e){
108	<	unexpectedException();
109	<	}
419	>	s.release(-1);
420	>	shouldThrow();
421	>	} catch (IllegalArgumentException success) {}
422		}
423
424		/**
425	<	* A release in one thread enables an acquire in another thread
425	>	* reducePermits(-N) throws IllegalArgumentException
426		*/
427	<	public void testAcquireReleaseInDifferentThreads() {
428	<	final Semaphore s = new Semaphore(0);
429	<	Thread t = new Thread(new Runnable() {
430	<	public void run() {
119	<	try {
120	<	s.acquire();
121	<	s.release();
122	<	s.release();
123	<	s.acquire();
124	<	} catch(InterruptedException ie){
125	<	threadUnexpectedException();
126	<	}
127	<	}
128	<	});
427	>	public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
428	>	public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
429	>	public void testReducePermitsIAE(boolean fair) {
430	>	PublicSemaphore s = new PublicSemaphore(10, fair);
431		try {
432	<	t.start();
433	<	Thread.sleep(SHORT_DELAY_MS);
434	<	s.release();
435	<	s.release();
432	>	s.reducePermits(-1);
433	>	shouldThrow();
434	>	} catch (IllegalArgumentException success) {}
435	>	}
436	>
437	>	/**
438	>	* reducePermits reduces number of permits
439	>	*/
440	>	public void testReducePermits()      { testReducePermits(false); }
441	>	public void testReducePermits_fair() { testReducePermits(true); }
442	>	public void testReducePermits(boolean fair) {
443	>	PublicSemaphore s = new PublicSemaphore(10, fair);
444	>	assertEquals(10, s.availablePermits());
445	>	s.reducePermits(0);
446	>	assertEquals(10, s.availablePermits());
447	>	s.reducePermits(1);
448	>	assertEquals(9, s.availablePermits());
449	>	s.reducePermits(10);
450	>	assertEquals(-1, s.availablePermits());
451	>	s.reducePermits(10);
452	>	assertEquals(-11, s.availablePermits());
453	>	s.reducePermits(0);
454	>	assertEquals(-11, s.availablePermits());
455	>	}
456	>
457	>	/**
458	>	* a reserialized semaphore has same number of permits and
459	>	* fairness, but no queued threads
460	>	*/
461	>	public void testSerialization()      { testSerialization(false); }
462	>	public void testSerialization_fair() { testSerialization(true); }
463	>	public void testSerialization(boolean fair) {
464	>	try {
465	>	Semaphore s = new Semaphore(3, fair);
466		s.acquire();
467		s.acquire();
468		s.release();
469	<	t.join();
470	<	} catch( InterruptedException e){
471	<	unexpectedException();
469	>
470	>	Semaphore clone = serialClone(s);
471	>	assertEquals(fair, s.isFair());
472	>	assertEquals(fair, clone.isFair());
473	>	assertEquals(2, s.availablePermits());
474	>	assertEquals(2, clone.availablePermits());
475	>	clone.acquire();
476	>	clone.acquire();
477	>	clone.release();
478	>	assertEquals(2, s.availablePermits());
479	>	assertEquals(1, clone.availablePermits());
480	>	assertFalse(s.hasQueuedThreads());
481	>	assertFalse(clone.hasQueuedThreads());
482	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
483	>
484	>	{
485	>	PublicSemaphore s = new PublicSemaphore(0, fair);
486	>	Thread t = newStartedThread(new InterruptibleLockRunnable(s));
487	>	// waitForQueuedThreads(s); // suffers from "flicker", so ...
488	>	waitForQueuedThread(s, t);  // ... we use this instead
489	>	PublicSemaphore clone = serialClone(s);
490	>	assertEquals(fair, s.isFair());
491	>	assertEquals(fair, clone.isFair());
492	>	assertEquals(0, s.availablePermits());
493	>	assertEquals(0, clone.availablePermits());
494	>	assertTrue(s.hasQueuedThreads());
495	>	assertFalse(clone.hasQueuedThreads());
496	>	s.release();
497	>	awaitTermination(t);
498	>	assertFalse(s.hasQueuedThreads());
499	>	assertFalse(clone.hasQueuedThreads());
500		}
501		}
502
503		/**
504	<	* A release in one thread enables an uninterruptible acquire in another thread
504	>	* tryAcquire(n) succeeds when sufficient permits, else fails
505		*/
506	<	public void testUninterruptibleAcquireReleaseInDifferentThreads() {
507	<	final Semaphore s = new Semaphore(0);
508	<	Thread t = new Thread(new Runnable() {
509	<	public void run() {
510	<	s.acquireUninterruptibly();
511	<	s.release();
512	<	s.release();
513	<	s.acquireUninterruptibly();
514	<	}
515	<	});
516	<	try {
517	<	t.start();
158	<	Thread.sleep(SHORT_DELAY_MS);
159	<	s.release();
160	<	s.release();
161	<	s.acquireUninterruptibly();
162	<	s.acquireUninterruptibly();
163	<	s.release();
164	<	t.join();
165	<	} catch( InterruptedException e){
166	<	unexpectedException();
167	<	}
506	>	public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
507	>	public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
508	>	public void testTryAcquireNInSameThread(boolean fair) {
509	>	Semaphore s = new Semaphore(2, fair);
510	>	assertEquals(2, s.availablePermits());
511	>	assertFalse(s.tryAcquire(3));
512	>	assertEquals(2, s.availablePermits());
513	>	assertTrue(s.tryAcquire(2));
514	>	assertEquals(0, s.availablePermits());
515	>	assertFalse(s.tryAcquire(1));
516	>	assertFalse(s.tryAcquire(2));
517	>	assertEquals(0, s.availablePermits());
518		}
519
170	–
520		/**
521	<	*  A release in one thread enables a timed acquire in another thread
521	>	* acquire succeeds if permits available
522		*/
523	<	public void testTimedAcquireReleaseInDifferentThreads() {
524	<	final Semaphore s = new Semaphore(1);
525	<	Thread t = new Thread(new Runnable() {
526	<	public void run() {
527	<	try {
528	<	s.release();
529	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
530	<	s.release();
531	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
532	<
533	<	} catch(InterruptedException ie){
534	<	threadUnexpectedException();
535	<	}
536	<	}
537	<	});
538	<	try {
539	<	t.start();
540	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
541	<	s.release();
542	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
543	<	s.release();
544	<	s.release();
545	<	t.join();
546	<	} catch( InterruptedException e){
547	<	unexpectedException();
523	>	public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
524	>	public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
525	>	public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
526	>	public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
527	>	public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
528	>	public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
529	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
530	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
531	>	public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
532	>	public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
533	>	public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
534	>	public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
535	>	public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
536	>	public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
537	>	public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
538	>	public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
539	>	public void testReleaseAcquireSameThread(boolean fair,
540	>	final AcquireMethod acquirer) {
541	>	Semaphore s = new Semaphore(1, fair);
542	>	for (int i = 1; i < 6; i++) {
543	>	s.release(i);
544	>	assertEquals(1 + i, s.availablePermits());
545	>	try {
546	>	acquirer.acquire(s, i);
547	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
548	>	assertEquals(1, s.availablePermits());
549		}
550		}
551
552		/**
553	<	* A waiting acquire blocks interruptibly
554	<	*/
555	<	public void testAcquire_InterruptedException() {
556	<	final Semaphore s = new Semaphore(0);
557	<	Thread t = new Thread(new Runnable() {
558	<	public void run() {
559	<	try {
560	<	s.acquire();
561	<	threadShouldThrow();
562	<	} catch(InterruptedException success){}
563	<	}
564	<	});
565	<	t.start();
566	<	try {
567	<	Thread.sleep(SHORT_DELAY_MS);
568	<	t.interrupt();
569	<	t.join();
570	<	} catch(InterruptedException e){
571	<	unexpectedException();
572	<	}
573	<	}
574	<
575	<	/**
576	<	*  A waiting timed acquire blocks interruptibly
577	<	*/
578	<	public void testTryAcquire_InterruptedException() {
579	<	final Semaphore s = new Semaphore(0);
580	<	Thread t = new Thread(new Runnable() {
581	<	public void run() {
582	<	try {
583	<	s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
584	<	threadShouldThrow();
585	<	} catch(InterruptedException success){
586	<	}
587	<	}
588	<	});
589	<	t.start();
240	<	try {
241	<	Thread.sleep(SHORT_DELAY_MS);
242	<	t.interrupt();
243	<	t.join();
244	<	} catch(InterruptedException e){
245	<	unexpectedException();
553	>	* release in one thread enables acquire in another thread
554	>	*/
555	>	public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
556	>	public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
557	>	public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
558	>	public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
559	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
560	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
561	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
562	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
563	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
564	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
565	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
566	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
567	>	public void testReleaseAcquireDifferentThreads(boolean fair,
568	>	final AcquireMethod acquirer) {
569	>	final Semaphore s = new Semaphore(0, fair);
570	>	final int rounds = 4;
571	>	long startTime = System.nanoTime();
572	>	Thread t = newStartedThread(new CheckedRunnable() {
573	>	public void realRun() throws InterruptedException {
574	>	for (int i = 0; i < rounds; i++) {
575	>	assertFalse(s.hasQueuedThreads());
576	>	if (i % 2 == 0)
577	>	acquirer.acquire(s);
578	>	else
579	>	acquirer.acquire(s, 3);
580	>	}}});
581	>
582	>	for (int i = 0; i < rounds; i++) {
583	>	while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
584	>	Thread.yield();
585	>	assertTrue(t.isAlive());
586	>	if (i % 2 == 0)
587	>	s.release();
588	>	else
589	>	s.release(3);
590		}
591	+	awaitTermination(t);
592	+	assertEquals(0, s.availablePermits());
593	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
594		}
595
596		/**
597	<	* a deserialized serialized semaphore has same number of permits
597	>	* fair locks are strictly FIFO
598		*/
599	<	public void testSerialization() {
600	<	Semaphore l = new Semaphore(3);
601	<	try {
602	<	l.acquire();
603	<	l.release();
604	<	ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
605	<	ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
606	<	out.writeObject(l);
607	<	out.close();
608	<
609	<	ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
610	<	ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
611	<	Semaphore r = (Semaphore) in.readObject();
612	<	assertEquals(3, r.availablePermits());
613	<	r.acquire();
614	<	r.release();
615	<	} catch(Exception e){
616	<	unexpectedException();
617	<	}
599	>	public void testFairLocksFifo() {
600	>	final PublicSemaphore s = new PublicSemaphore(1, true);
601	>	final CountDownLatch pleaseRelease = new CountDownLatch(1);
602	>	Thread t1 = newStartedThread(new CheckedRunnable() {
603	>	public void realRun() throws InterruptedException {
604	>	// Will block; permits are available, but not three
605	>	s.acquire(3);
606	>	}});
607	>
608	>	waitForQueuedThread(s, t1);
609	>
610	>	Thread t2 = newStartedThread(new CheckedRunnable() {
611	>	public void realRun() throws InterruptedException {
612	>	// Will fail, even though 1 permit is available
613	>	assertFalse(s.tryAcquire(0L, MILLISECONDS));
614	>	assertFalse(s.tryAcquire(1, 0L, MILLISECONDS));
615	>
616	>	// untimed tryAcquire will barge and succeed
617	>	assertTrue(s.tryAcquire());
618	>	s.release(2);
619	>	assertTrue(s.tryAcquire(2));
620	>	s.release();
621	>
622	>	pleaseRelease.countDown();
623	>	// Will queue up behind t1, even though 1 permit is available
624	>	s.acquire();
625	>	}});
626	>
627	>	await(pleaseRelease);
628	>	waitForQueuedThread(s, t2);
629	>	s.release(2);
630	>	awaitTermination(t1);
631	>	assertTrue(t2.isAlive());
632	>	s.release();
633	>	awaitTermination(t2);
634	>	}
635	>
636	>	/**
637	>	* toString indicates current number of permits
638	>	*/
639	>	public void testToString()      { testToString(false); }
640	>	public void testToString_fair() { testToString(true); }
641	>	public void testToString(boolean fair) {
642	>	PublicSemaphore s = new PublicSemaphore(0, fair);
643	>	assertTrue(s.toString().contains("Permits = 0"));
644	>	s.release();
645	>	assertTrue(s.toString().contains("Permits = 1"));
646	>	s.release(2);
647	>	assertTrue(s.toString().contains("Permits = 3"));
648	>	s.reducePermits(5);
649	>	assertTrue(s.toString().contains("Permits = -2"));
650		}
651
652		}

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