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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 1.37 by jsr166, Sat May 13 23:50:00 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	>
15	>	import junit.framework.AssertionFailedError;
16	>	import junit.framework.Test;
17	>	import junit.framework.TestSuite;
18
19		public class SemaphoreTest extends JSR166TestCase {
20		public static void main(String[] args) {
21	<	junit.textui.TestRunner.run (suite());
21	>	main(suite(), args);
22		}
23		public static Test suite() {
24	<	return new TestSuite(SemaphoreTest.class);
24	>	return new TestSuite(SemaphoreTest.class);
25	>	}
26	>
27	>	/**
28	>	* Subclass to expose protected methods
29	>	*/
30	>	static class PublicSemaphore extends Semaphore {
31	>	PublicSemaphore(int permits) { super(permits); }
32	>	PublicSemaphore(int permits, boolean fair) { super(permits, fair); }
33	>	public Collection<Thread> getQueuedThreads() {
34	>	return super.getQueuedThreads();
35	>	}
36	>	public boolean hasQueuedThread(Thread t) {
37	>	return super.getQueuedThreads().contains(t);
38	>	}
39	>	public void reducePermits(int reduction) {
40	>	super.reducePermits(reduction);
41	>	}
42	>	}
43	>
44	>	/**
45	>	* A runnable calling acquire
46	>	*/
47	>	class InterruptibleLockRunnable extends CheckedRunnable {
48	>	final Semaphore lock;
49	>	InterruptibleLockRunnable(Semaphore s) { lock = s; }
50	>	public void realRun() {
51	>	try {
52	>	lock.acquire();
53	>	}
54	>	catch (InterruptedException ignored) {}
55	>	}
56	>	}
57	>
58	>	/**
59	>	* A runnable calling acquire that expects to be interrupted
60	>	*/
61	>	class InterruptedLockRunnable extends CheckedInterruptedRunnable {
62	>	final Semaphore lock;
63	>	InterruptedLockRunnable(Semaphore s) { lock = s; }
64	>	public void realRun() throws InterruptedException {
65	>	lock.acquire();
66	>	}
67	>	}
68	>
69	>	/**
70	>	* Spin-waits until s.hasQueuedThread(t) becomes true.
71	>	*/
72	>	void waitForQueuedThread(PublicSemaphore s, Thread t) {
73	>	long startTime = System.nanoTime();
74	>	while (!s.hasQueuedThread(t)) {
75	>	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
76	>	throw new AssertionFailedError("timed out");
77	>	Thread.yield();
78	>	}
79	>	assertTrue(s.hasQueuedThreads());
80	>	assertTrue(t.isAlive());
81	>	}
82	>
83	>	/**
84	>	* Spin-waits until s.hasQueuedThreads() becomes true.
85	>	*/
86	>	void waitForQueuedThreads(Semaphore s) {
87	>	long startTime = System.nanoTime();
88	>	while (!s.hasQueuedThreads()) {
89	>	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
90	>	throw new AssertionFailedError("timed out");
91	>	Thread.yield();
92	>	}
93	>	}
94	>
95	>	enum AcquireMethod {
96	>	acquire() {
97	>	void acquire(Semaphore s) throws InterruptedException {
98	>	s.acquire();
99	>	}
100	>	},
101	>	acquireN() {
102	>	void acquire(Semaphore s, int permits) throws InterruptedException {
103	>	s.acquire(permits);
104	>	}
105	>	},
106	>	acquireUninterruptibly() {
107	>	void acquire(Semaphore s) {
108	>	s.acquireUninterruptibly();
109	>	}
110	>	},
111	>	acquireUninterruptiblyN() {
112	>	void acquire(Semaphore s, int permits) {
113	>	s.acquireUninterruptibly(permits);
114	>	}
115	>	},
116	>	tryAcquire() {
117	>	void acquire(Semaphore s) {
118	>	assertTrue(s.tryAcquire());
119	>	}
120	>	},
121	>	tryAcquireN() {
122	>	void acquire(Semaphore s, int permits) {
123	>	assertTrue(s.tryAcquire(permits));
124	>	}
125	>	},
126	>	tryAcquireTimed() {
127	>	void acquire(Semaphore s) throws InterruptedException {
128	>	assertTrue(s.tryAcquire(2 * LONG_DELAY_MS, MILLISECONDS));
129	>	}
130	>	},
131	>	tryAcquireTimedN {
132	>	void acquire(Semaphore s, int permits) throws InterruptedException {
133	>	assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS));
134	>	}
135	>	};
136	>
137	>	// Intentionally meta-circular
138	>
139	>	/** Acquires 1 permit. */
140	>	void acquire(Semaphore s) throws InterruptedException {
141	>	acquire(s, 1);
142	>	}
143	>	/** Acquires the given number of permits. */
144	>	void acquire(Semaphore s, int permits) throws InterruptedException {
145	>	for (int i = 0; i < permits; i++)
146	>	acquire(s);
147	>	}
148		}
149
150		/**
151		* Zero, negative, and positive initial values are allowed in constructor
152		*/
153	<	public void testConstructor() {
154	<	Semaphore s0 = new Semaphore(0);
155	<	assertEquals(0, s0.availablePermits());
156	<	Semaphore s1 = new Semaphore(-1);
157	<	assertEquals(-1, s1.availablePermits());
158	<	Semaphore s2 = new Semaphore(-1);
159	<	assertEquals(-1, s2.availablePermits());
153	>	public void testConstructor()      { testConstructor(false); }
154	>	public void testConstructor_fair() { testConstructor(true); }
155	>	public void testConstructor(boolean fair) {
156	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
157	>	Semaphore s = new Semaphore(permits, fair);
158	>	assertEquals(permits, s.availablePermits());
159	>	assertEquals(fair, s.isFair());
160	>	}
161	>	}
162	>
163	>	/**
164	>	* Constructor without fairness argument behaves as nonfair
165	>	*/
166	>	public void testConstructorDefaultsToNonFair() {
167	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
168	>	Semaphore s = new Semaphore(permits);
169	>	assertEquals(permits, s.availablePermits());
170	>	assertFalse(s.isFair());
171	>	}
172		}
173
174		/**
175	<	* tryAcquire succeeds when sufficent permits, else fails
175	>	* tryAcquire succeeds when sufficient permits, else fails
176		*/
177	<	public void testTryAcquireInSameThread() {
178	<	Semaphore s = new Semaphore(2);
177	>	public void testTryAcquireInSameThread()      { testTryAcquireInSameThread(false); }
178	>	public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); }
179	>	public void testTryAcquireInSameThread(boolean fair) {
180	>	Semaphore s = new Semaphore(2, fair);
181		assertEquals(2, s.availablePermits());
182		assertTrue(s.tryAcquire());
183		assertTrue(s.tryAcquire());
184		assertEquals(0, s.availablePermits());
185		assertFalse(s.tryAcquire());
186	+	assertFalse(s.tryAcquire());
187	+	assertEquals(0, s.availablePermits());
188		}
189
190		/**
191	<	* Acquire and release of semaphore succeed if initially available
191	>	* timed tryAcquire times out
192		*/
193	<	public void testAcquireReleaseInSameThread() {
194	<	Semaphore s = new Semaphore(1);
195	<	try {
196	<	s.acquire();
197	<	s.release();
198	<	s.acquire();
199	<	s.release();
200	<	s.acquire();
201	<	s.release();
202	<	s.acquire();
203	<	s.release();
204	<	s.acquire();
205	<	s.release();
206	<	assertEquals(1, s.availablePermits());
207	<	} catch( InterruptedException e){
208	<	unexpectedException();
209	<	}
193	>	public void testTryAcquire_timeout()      { testTryAcquire_timeout(false); }
194	>	public void testTryAcquire_timeout_fair() { testTryAcquire_timeout(true); }
195	>	public void testTryAcquire_timeout(boolean fair) {
196	>	Semaphore s = new Semaphore(0, fair);
197	>	long startTime = System.nanoTime();
198	>	try { assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS)); }
199	>	catch (InterruptedException e) { threadUnexpectedException(e); }
200	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
201	>	}
202	>
203	>	/**
204	>	* timed tryAcquire(N) times out
205	>	*/
206	>	public void testTryAcquireN_timeout()      { testTryAcquireN_timeout(false); }
207	>	public void testTryAcquireN_timeout_fair() { testTryAcquireN_timeout(true); }
208	>	public void testTryAcquireN_timeout(boolean fair) {
209	>	Semaphore s = new Semaphore(2, fair);
210	>	long startTime = System.nanoTime();
211	>	try { assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS)); }
212	>	catch (InterruptedException e) { threadUnexpectedException(e); }
213	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
214	>	}
215	>
216	>	/**
217	>	* acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
218	>	* are interruptible
219	>	*/
220	>	public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
221	>	public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
222	>	public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
223	>	public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
224	>	public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
225	>	public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
226	>	public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
227	>	public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
228	>	public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
229	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
230	>	final Semaphore pleaseInterrupt = new Semaphore(0, fair);
231	>	Thread t = newStartedThread(new CheckedRunnable() {
232	>	public void realRun() {
233	>	// Interrupt before acquire
234	>	Thread.currentThread().interrupt();
235	>	try {
236	>	acquirer.acquire(s);
237	>	shouldThrow();
238	>	} catch (InterruptedException success) {}
239	>
240	>	// Interrupt during acquire
241	>	try {
242	>	acquirer.acquire(s);
243	>	shouldThrow();
244	>	} catch (InterruptedException success) {}
245	>
246	>	// Interrupt before acquire(N)
247	>	Thread.currentThread().interrupt();
248	>	try {
249	>	acquirer.acquire(s, 3);
250	>	shouldThrow();
251	>	} catch (InterruptedException success) {}
252	>
253	>	pleaseInterrupt.release();
254	>
255	>	// Interrupt during acquire(N)
256	>	try {
257	>	acquirer.acquire(s, 3);
258	>	shouldThrow();
259	>	} catch (InterruptedException success) {}
260	>	}});
261	>
262	>	waitForQueuedThread(s, t);
263	>	t.interrupt();
264	>	await(pleaseInterrupt);
265	>	waitForQueuedThread(s, t);
266	>	t.interrupt();
267	>	awaitTermination(t);
268	>	}
269	>
270	>	/**
271	>	* acquireUninterruptibly(), acquireUninterruptibly(N) are
272	>	* uninterruptible
273	>	*/
274	>	public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
275	>	public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
276	>	public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
277	>	public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
278	>	public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
279	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
280	>	final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
281	>
282	>	Thread t1 = newStartedThread(new CheckedRunnable() {
283	>	public void realRun() throws InterruptedException {
284	>	// Interrupt before acquire
285	>	pleaseInterrupt.release();
286	>	Thread.currentThread().interrupt();
287	>	acquirer.acquire(s);
288	>	assertTrue(Thread.interrupted());
289	>	}});
290	>
291	>	Thread t2 = newStartedThread(new CheckedRunnable() {
292	>	public void realRun() throws InterruptedException {
293	>	// Interrupt during acquire
294	>	pleaseInterrupt.release();
295	>	acquirer.acquire(s);
296	>	assertTrue(Thread.interrupted());
297	>	}});
298	>
299	>	await(pleaseInterrupt);
300	>	waitForQueuedThread(s, t1);
301	>	waitForQueuedThread(s, t2);
302	>	t2.interrupt();
303	>
304	>	assertThreadBlocks(t1, Thread.State.WAITING);
305	>	assertThreadBlocks(t2, Thread.State.WAITING);
306	>
307	>	s.release(2);
308	>
309	>	awaitTermination(t1);
310	>	awaitTermination(t2);
311	>	}
312	>
313	>	/**
314	>	* hasQueuedThreads reports whether there are waiting threads
315	>	*/
316	>	public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
317	>	public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
318	>	public void testHasQueuedThreads(boolean fair) {
319	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
320	>	assertFalse(lock.hasQueuedThreads());
321	>	lock.acquireUninterruptibly();
322	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
323	>	waitForQueuedThread(lock, t1);
324	>	assertTrue(lock.hasQueuedThreads());
325	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
326	>	waitForQueuedThread(lock, t2);
327	>	assertTrue(lock.hasQueuedThreads());
328	>	t1.interrupt();
329	>	awaitTermination(t1);
330	>	assertTrue(lock.hasQueuedThreads());
331	>	lock.release();
332	>	awaitTermination(t2);
333	>	assertFalse(lock.hasQueuedThreads());
334	>	}
335	>
336	>	/**
337	>	* getQueueLength reports number of waiting threads
338	>	*/
339	>	public void testGetQueueLength()      { testGetQueueLength(false); }
340	>	public void testGetQueueLength_fair() { testGetQueueLength(true); }
341	>	public void testGetQueueLength(boolean fair) {
342	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
343	>	assertEquals(0, lock.getQueueLength());
344	>	lock.acquireUninterruptibly();
345	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
346	>	waitForQueuedThread(lock, t1);
347	>	assertEquals(1, lock.getQueueLength());
348	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
349	>	waitForQueuedThread(lock, t2);
350	>	assertEquals(2, lock.getQueueLength());
351	>	t1.interrupt();
352	>	awaitTermination(t1);
353	>	assertEquals(1, lock.getQueueLength());
354	>	lock.release();
355	>	awaitTermination(t2);
356	>	assertEquals(0, lock.getQueueLength());
357	>	}
358	>
359	>	/**
360	>	* getQueuedThreads includes waiting threads
361	>	*/
362	>	public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
363	>	public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
364	>	public void testGetQueuedThreads(boolean fair) {
365	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
366	>	assertTrue(lock.getQueuedThreads().isEmpty());
367	>	lock.acquireUninterruptibly();
368	>	assertTrue(lock.getQueuedThreads().isEmpty());
369	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
370	>	waitForQueuedThread(lock, t1);
371	>	assertTrue(lock.getQueuedThreads().contains(t1));
372	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
373	>	waitForQueuedThread(lock, t2);
374	>	assertTrue(lock.getQueuedThreads().contains(t1));
375	>	assertTrue(lock.getQueuedThreads().contains(t2));
376	>	t1.interrupt();
377	>	awaitTermination(t1);
378	>	assertFalse(lock.getQueuedThreads().contains(t1));
379	>	assertTrue(lock.getQueuedThreads().contains(t2));
380	>	lock.release();
381	>	awaitTermination(t2);
382	>	assertTrue(lock.getQueuedThreads().isEmpty());
383	>	}
384	>
385	>	/**
386	>	* drainPermits reports and removes given number of permits
387	>	*/
388	>	public void testDrainPermits()      { testDrainPermits(false); }
389	>	public void testDrainPermits_fair() { testDrainPermits(true); }
390	>	public void testDrainPermits(boolean fair) {
391	>	Semaphore s = new Semaphore(0, fair);
392	>	assertEquals(0, s.availablePermits());
393	>	assertEquals(0, s.drainPermits());
394	>	s.release(10);
395	>	assertEquals(10, s.availablePermits());
396	>	assertEquals(10, s.drainPermits());
397	>	assertEquals(0, s.availablePermits());
398	>	assertEquals(0, s.drainPermits());
399		}
400
401		/**
402	<	* Uninterruptible acquire and release of semaphore succeed if
69	<	* initially available
402	>	* release(-N) throws IllegalArgumentException
403		*/
404	<	public void testAcquireUninterruptiblyReleaseInSameThread() {
405	<	Semaphore s = new Semaphore(1);
404	>	public void testReleaseIAE()      { testReleaseIAE(false); }
405	>	public void testReleaseIAE_fair() { testReleaseIAE(true); }
406	>	public void testReleaseIAE(boolean fair) {
407	>	Semaphore s = new Semaphore(10, fair);
408		try {
409	<	s.acquireUninterruptibly();
410	<	s.release();
411	<	s.acquireUninterruptibly();
77	<	s.release();
78	<	s.acquireUninterruptibly();
79	<	s.release();
80	<	s.acquireUninterruptibly();
81	<	s.release();
82	<	s.acquireUninterruptibly();
83	<	s.release();
84	<	assertEquals(1, s.availablePermits());
85	<	} finally {
86	<	}
409	>	s.release(-1);
410	>	shouldThrow();
411	>	} catch (IllegalArgumentException success) {}
412		}
413
414		/**
415	<	* Timed Acquire and release of semaphore succeed if
91	<	* initially available
415	>	* reducePermits(-N) throws IllegalArgumentException
416		*/
417	<	public void testTimedAcquireReleaseInSameThread() {
418	<	Semaphore s = new Semaphore(1);
417	>	public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
418	>	public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
419	>	public void testReducePermitsIAE(boolean fair) {
420	>	PublicSemaphore s = new PublicSemaphore(10, fair);
421		try {
422	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
423	<	s.release();
424	<	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	<	}
422	>	s.reducePermits(-1);
423	>	shouldThrow();
424	>	} catch (IllegalArgumentException success) {}
425		}
426
427		/**
428	<	* A release in one thread enables an acquire in another thread
429	<	*/
430	<	public void testAcquireReleaseInDifferentThreads() {
431	<	final Semaphore s = new Semaphore(0);
432	<	Thread t = new Thread(new Runnable() {
433	<	public void run() {
434	<	try {
435	<	s.acquire();
436	<	s.release();
437	<	s.release();
438	<	s.acquire();
439	<	} catch(InterruptedException ie){
440	<	threadUnexpectedException();
441	<	}
442	<	}
443	<	});
428	>	* reducePermits reduces number of permits
429	>	*/
430	>	public void testReducePermits()      { testReducePermits(false); }
431	>	public void testReducePermits_fair() { testReducePermits(true); }
432	>	public void testReducePermits(boolean fair) {
433	>	PublicSemaphore s = new PublicSemaphore(10, fair);
434	>	assertEquals(10, s.availablePermits());
435	>	s.reducePermits(0);
436	>	assertEquals(10, s.availablePermits());
437	>	s.reducePermits(1);
438	>	assertEquals(9, s.availablePermits());
439	>	s.reducePermits(10);
440	>	assertEquals(-1, s.availablePermits());
441	>	s.reducePermits(10);
442	>	assertEquals(-11, s.availablePermits());
443	>	s.reducePermits(0);
444	>	assertEquals(-11, s.availablePermits());
445	>	}
446	>
447	>	/**
448	>	* a reserialized semaphore has same number of permits and
449	>	* fairness, but no queued threads
450	>	*/
451	>	public void testSerialization()      { testSerialization(false); }
452	>	public void testSerialization_fair() { testSerialization(true); }
453	>	public void testSerialization(boolean fair) {
454		try {
455	<	t.start();
131	<	Thread.sleep(SHORT_DELAY_MS);
132	<	s.release();
133	<	s.release();
455	>	Semaphore s = new Semaphore(3, fair);
456		s.acquire();
457		s.acquire();
458		s.release();
459	<	t.join();
460	<	} catch( InterruptedException e){
461	<	unexpectedException();
459	>
460	>	Semaphore clone = serialClone(s);
461	>	assertEquals(fair, s.isFair());
462	>	assertEquals(fair, clone.isFair());
463	>	assertEquals(2, s.availablePermits());
464	>	assertEquals(2, clone.availablePermits());
465	>	clone.acquire();
466	>	clone.acquire();
467	>	clone.release();
468	>	assertEquals(2, s.availablePermits());
469	>	assertEquals(1, clone.availablePermits());
470	>	assertFalse(s.hasQueuedThreads());
471	>	assertFalse(clone.hasQueuedThreads());
472	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
473	>
474	>	{
475	>	PublicSemaphore s = new PublicSemaphore(0, fair);
476	>	Thread t = newStartedThread(new InterruptibleLockRunnable(s));
477	>	// waitForQueuedThreads(s); // suffers from "flicker", so ...
478	>	waitForQueuedThread(s, t);  // ... we use this instead
479	>	PublicSemaphore clone = serialClone(s);
480	>	assertEquals(fair, s.isFair());
481	>	assertEquals(fair, clone.isFair());
482	>	assertEquals(0, s.availablePermits());
483	>	assertEquals(0, clone.availablePermits());
484	>	assertTrue(s.hasQueuedThreads());
485	>	assertFalse(clone.hasQueuedThreads());
486	>	s.release();
487	>	awaitTermination(t);
488	>	assertFalse(s.hasQueuedThreads());
489	>	assertFalse(clone.hasQueuedThreads());
490		}
491		}
492
493		/**
494	<	* A release in one thread enables an uninterruptible acquire in another thread
494	>	* tryAcquire(n) succeeds when sufficient permits, else fails
495		*/
496	<	public void testUninterruptibleAcquireReleaseInDifferentThreads() {
497	<	final Semaphore s = new Semaphore(0);
498	<	Thread t = new Thread(new Runnable() {
499	<	public void run() {
500	<	s.acquireUninterruptibly();
501	<	s.release();
502	<	s.release();
503	<	s.acquireUninterruptibly();
504	<	}
505	<	});
506	<	try {
507	<	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	<	}
496	>	public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
497	>	public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
498	>	public void testTryAcquireNInSameThread(boolean fair) {
499	>	Semaphore s = new Semaphore(2, fair);
500	>	assertEquals(2, s.availablePermits());
501	>	assertFalse(s.tryAcquire(3));
502	>	assertEquals(2, s.availablePermits());
503	>	assertTrue(s.tryAcquire(2));
504	>	assertEquals(0, s.availablePermits());
505	>	assertFalse(s.tryAcquire(1));
506	>	assertFalse(s.tryAcquire(2));
507	>	assertEquals(0, s.availablePermits());
508		}
509
170	–
510		/**
511	<	*  A release in one thread enables a timed acquire in another thread
511	>	* acquire succeeds if permits available
512		*/
513	<	public void testTimedAcquireReleaseInDifferentThreads() {
514	<	final Semaphore s = new Semaphore(1);
515	<	Thread t = new Thread(new Runnable() {
516	<	public void run() {
517	<	try {
518	<	s.release();
519	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
520	<	s.release();
521	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
522	<
523	<	} catch(InterruptedException ie){
524	<	threadUnexpectedException();
525	<	}
526	<	}
527	<	});
528	<	try {
529	<	t.start();
530	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
531	<	s.release();
532	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
533	<	s.release();
534	<	s.release();
535	<	t.join();
536	<	} catch( InterruptedException e){
537	<	unexpectedException();
513	>	public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
514	>	public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
515	>	public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
516	>	public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
517	>	public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
518	>	public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
519	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
520	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
521	>	public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
522	>	public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
523	>	public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
524	>	public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
525	>	public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
526	>	public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
527	>	public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
528	>	public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
529	>	public void testReleaseAcquireSameThread(boolean fair,
530	>	final AcquireMethod acquirer) {
531	>	Semaphore s = new Semaphore(1, fair);
532	>	for (int i = 1; i < 6; i++) {
533	>	s.release(i);
534	>	assertEquals(1 + i, s.availablePermits());
535	>	try {
536	>	acquirer.acquire(s, i);
537	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
538	>	assertEquals(1, s.availablePermits());
539		}
540		}
541
542		/**
543	<	* A waiting acquire blocks interruptibly
544	<	*/
545	<	public void testAcquire_InterruptedException() {
546	<	final Semaphore s = new Semaphore(0);
547	<	Thread t = new Thread(new Runnable() {
548	<	public void run() {
549	<	try {
550	<	s.acquire();
551	<	threadShouldThrow();
552	<	} catch(InterruptedException success){}
553	<	}
554	<	});
555	<	t.start();
556	<	try {
557	<	Thread.sleep(SHORT_DELAY_MS);
558	<	t.interrupt();
559	<	t.join();
560	<	} catch(InterruptedException e){
561	<	unexpectedException();
562	<	}
563	<	}
564	<
565	<	/**
566	<	*  A waiting timed acquire blocks interruptibly
567	<	*/
568	<	public void testTryAcquire_InterruptedException() {
569	<	final Semaphore s = new Semaphore(0);
570	<	Thread t = new Thread(new Runnable() {
571	<	public void run() {
572	<	try {
573	<	s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
574	<	threadShouldThrow();
575	<	} catch(InterruptedException success){
576	<	}
577	<	}
578	<	});
579	<	t.start();
240	<	try {
241	<	Thread.sleep(SHORT_DELAY_MS);
242	<	t.interrupt();
243	<	t.join();
244	<	} catch(InterruptedException e){
245	<	unexpectedException();
543	>	* release in one thread enables acquire in another thread
544	>	*/
545	>	public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
546	>	public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
547	>	public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
548	>	public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
549	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
550	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
551	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
552	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
553	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
554	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
555	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
556	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
557	>	public void testReleaseAcquireDifferentThreads(boolean fair,
558	>	final AcquireMethod acquirer) {
559	>	final Semaphore s = new Semaphore(0, fair);
560	>	final int rounds = 4;
561	>	long startTime = System.nanoTime();
562	>	Thread t = newStartedThread(new CheckedRunnable() {
563	>	public void realRun() throws InterruptedException {
564	>	for (int i = 0; i < rounds; i++) {
565	>	assertFalse(s.hasQueuedThreads());
566	>	if (i % 2 == 0)
567	>	acquirer.acquire(s);
568	>	else
569	>	acquirer.acquire(s, 3);
570	>	}}});
571	>
572	>	for (int i = 0; i < rounds; i++) {
573	>	while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
574	>	Thread.yield();
575	>	assertTrue(t.isAlive());
576	>	if (i % 2 == 0)
577	>	s.release();
578	>	else
579	>	s.release(3);
580		}
581	+	awaitTermination(t);
582	+	assertEquals(0, s.availablePermits());
583	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
584		}
585
586		/**
587	<	* a deserialized serialized semaphore has same number of permits
587	>	* fair locks are strictly FIFO
588		*/
589	<	public void testSerialization() {
590	<	Semaphore l = new Semaphore(3);
591	<	try {
592	<	l.acquire();
593	<	l.release();
594	<	ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
595	<	ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
596	<	out.writeObject(l);
597	<	out.close();
598	<
599	<	ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
600	<	ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
601	<	Semaphore r = (Semaphore) in.readObject();
602	<	assertEquals(3, r.availablePermits());
603	<	r.acquire();
604	<	r.release();
605	<	} catch(Exception e){
606	<	unexpectedException();
607	<	}
589	>	public void testFairLocksFifo() {
590	>	final PublicSemaphore s = new PublicSemaphore(1, true);
591	>	final CountDownLatch pleaseRelease = new CountDownLatch(1);
592	>	Thread t1 = newStartedThread(new CheckedRunnable() {
593	>	public void realRun() throws InterruptedException {
594	>	// Will block; permits are available, but not three
595	>	s.acquire(3);
596	>	}});
597	>
598	>	waitForQueuedThread(s, t1);
599	>
600	>	Thread t2 = newStartedThread(new CheckedRunnable() {
601	>	public void realRun() throws InterruptedException {
602	>	// Will fail, even though 1 permit is available
603	>	assertFalse(s.tryAcquire(0L, MILLISECONDS));
604	>	assertFalse(s.tryAcquire(1, 0L, MILLISECONDS));
605	>
606	>	// untimed tryAcquire will barge and succeed
607	>	assertTrue(s.tryAcquire());
608	>	s.release(2);
609	>	assertTrue(s.tryAcquire(2));
610	>	s.release();
611	>
612	>	pleaseRelease.countDown();
613	>	// Will queue up behind t1, even though 1 permit is available
614	>	s.acquire();
615	>	}});
616	>
617	>	await(pleaseRelease);
618	>	waitForQueuedThread(s, t2);
619	>	s.release(2);
620	>	awaitTermination(t1);
621	>	assertTrue(t2.isAlive());
622	>	s.release();
623	>	awaitTermination(t2);
624	>	}
625	>
626	>	/**
627	>	* toString indicates current number of permits
628	>	*/
629	>	public void testToString()      { testToString(false); }
630	>	public void testToString_fair() { testToString(true); }
631	>	public void testToString(boolean fair) {
632	>	PublicSemaphore s = new PublicSemaphore(0, fair);
633	>	assertTrue(s.toString().contains("Permits = 0"));
634	>	s.release();
635	>	assertTrue(s.toString().contains("Permits = 1"));
636	>	s.release(2);
637	>	assertTrue(s.toString().contains("Permits = 3"));
638	>	s.reducePermits(5);
639	>	assertTrue(s.toString().contains("Permits = -2"));
640		}
641
642		}

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