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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 1.45 by jsr166, Tue Aug 13 00:46:27 2019 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.Test;
16	>	import junit.framework.TestSuite;
17
18		public class SemaphoreTest extends JSR166TestCase {
19		public static void main(String[] args) {
20	<	junit.textui.TestRunner.run (suite());
20	>	main(suite(), args);
21		}
22		public static Test suite() {
23	<	return new TestSuite(SemaphoreTest.class);
23	>	return new TestSuite(SemaphoreTest.class);
24	>	}
25	>
26	>	/**
27	>	* Subclass to expose protected methods
28	>	*/
29	>	static class PublicSemaphore extends Semaphore {
30	>	PublicSemaphore(int permits) { super(permits); }
31	>	PublicSemaphore(int permits, boolean fair) { super(permits, fair); }
32	>	public Collection<Thread> getQueuedThreads() {
33	>	return super.getQueuedThreads();
34	>	}
35	>	public boolean hasQueuedThread(Thread t) {
36	>	return super.getQueuedThreads().contains(t);
37	>	}
38	>	public void reducePermits(int reduction) {
39	>	super.reducePermits(reduction);
40	>	}
41	>	}
42	>
43	>	/**
44	>	* A runnable calling acquire
45	>	*/
46	>	class InterruptibleLockRunnable extends CheckedRunnable {
47	>	final Semaphore lock;
48	>	InterruptibleLockRunnable(Semaphore s) { lock = s; }
49	>	public void realRun() {
50	>	try {
51	>	lock.acquire();
52	>	}
53	>	catch (InterruptedException ignored) {}
54	>	}
55	>	}
56	>
57	>	/**
58	>	* A runnable calling acquire that expects to be interrupted
59	>	*/
60	>	class InterruptedLockRunnable extends CheckedInterruptedRunnable {
61	>	final Semaphore lock;
62	>	InterruptedLockRunnable(Semaphore s) { lock = s; }
63	>	public void realRun() throws InterruptedException {
64	>	lock.acquire();
65	>	}
66	>	}
67	>
68	>	/**
69	>	* Spin-waits until s.hasQueuedThread(t) becomes true.
70	>	*/
71	>	void waitForQueuedThread(PublicSemaphore s, Thread t) {
72	>	long startTime = System.nanoTime();
73	>	while (!s.hasQueuedThread(t)) {
74	>	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
75	>	throw new AssertionError("timed out");
76	>	Thread.yield();
77	>	}
78	>	assertTrue(s.hasQueuedThreads());
79	>	assertTrue(t.isAlive());
80	>	}
81	>
82	>	/**
83	>	* Spin-waits until s.hasQueuedThreads() becomes true.
84	>	*/
85	>	void waitForQueuedThreads(Semaphore s) {
86	>	long startTime = System.nanoTime();
87	>	while (!s.hasQueuedThreads()) {
88	>	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
89	>	throw new AssertionError("timed out");
90	>	Thread.yield();
91	>	}
92	>	}
93	>
94	>	enum AcquireMethod {
95	>	acquire() {
96	>	void acquire(Semaphore s) throws InterruptedException {
97	>	s.acquire();
98	>	}
99	>	},
100	>	acquireN() {
101	>	void acquire(Semaphore s, int permits) throws InterruptedException {
102	>	s.acquire(permits);
103	>	}
104	>	},
105	>	acquireUninterruptibly() {
106	>	void acquire(Semaphore s) {
107	>	s.acquireUninterruptibly();
108	>	}
109	>	},
110	>	acquireUninterruptiblyN() {
111	>	void acquire(Semaphore s, int permits) {
112	>	s.acquireUninterruptibly(permits);
113	>	}
114	>	},
115	>	tryAcquire() {
116	>	void acquire(Semaphore s) {
117	>	assertTrue(s.tryAcquire());
118	>	}
119	>	},
120	>	tryAcquireN() {
121	>	void acquire(Semaphore s, int permits) {
122	>	assertTrue(s.tryAcquire(permits));
123	>	}
124	>	},
125	>	tryAcquireTimed() {
126	>	void acquire(Semaphore s) throws InterruptedException {
127	>	assertTrue(s.tryAcquire(2 * LONG_DELAY_MS, MILLISECONDS));
128	>	}
129	>	Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
130	>	},
131	>	tryAcquireTimedN {
132	>	void acquire(Semaphore s, int permits) throws InterruptedException {
133	>	assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS));
134	>	}
135	>	Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
136	>	};
137	>
138	>	// Intentionally meta-circular
139	>
140	>	/** Acquires 1 permit. */
141	>	void acquire(Semaphore s) throws InterruptedException {
142	>	acquire(s, 1);
143	>	}
144	>	/** Acquires the given number of permits. */
145	>	void acquire(Semaphore s, int permits) throws InterruptedException {
146	>	for (int i = 0; i < permits; i++)
147	>	acquire(s);
148	>	}
149	>	Thread.State parkedState() { return Thread.State.WAITING; }
150		}
151
152		/**
153		* Zero, negative, and positive initial values are allowed in constructor
154		*/
155	<	public void testConstructor() {
156	<	Semaphore s0 = new Semaphore(0);
157	<	assertEquals(0, s0.availablePermits());
158	<	Semaphore s1 = new Semaphore(-1);
159	<	assertEquals(-1, s1.availablePermits());
160	<	Semaphore s2 = new Semaphore(-1);
161	<	assertEquals(-1, s2.availablePermits());
155	>	public void testConstructor()      { testConstructor(false); }
156	>	public void testConstructor_fair() { testConstructor(true); }
157	>	public void testConstructor(boolean fair) {
158	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
159	>	Semaphore s = new Semaphore(permits, fair);
160	>	assertEquals(permits, s.availablePermits());
161	>	assertEquals(fair, s.isFair());
162	>	}
163	>	}
164	>
165	>	/**
166	>	* Constructor without fairness argument behaves as nonfair
167	>	*/
168	>	public void testConstructorDefaultsToNonFair() {
169	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
170	>	Semaphore s = new Semaphore(permits);
171	>	assertEquals(permits, s.availablePermits());
172	>	assertFalse(s.isFair());
173	>	}
174		}
175
176		/**
177	<	* tryAcquire succeeds when sufficent permits, else fails
177	>	* tryAcquire succeeds when sufficient permits, else fails
178		*/
179	<	public void testTryAcquireInSameThread() {
180	<	Semaphore s = new Semaphore(2);
179	>	public void testTryAcquireInSameThread()      { testTryAcquireInSameThread(false); }
180	>	public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); }
181	>	public void testTryAcquireInSameThread(boolean fair) {
182	>	Semaphore s = new Semaphore(2, fair);
183		assertEquals(2, s.availablePermits());
184		assertTrue(s.tryAcquire());
185		assertTrue(s.tryAcquire());
186		assertEquals(0, s.availablePermits());
187		assertFalse(s.tryAcquire());
188	+	assertFalse(s.tryAcquire());
189	+	assertEquals(0, s.availablePermits());
190		}
191
192		/**
193	<	* Acquire and release of semaphore succeed if initially available
193	>	* timed tryAcquire times out
194		*/
195	<	public void testAcquireReleaseInSameThread() {
196	<	Semaphore s = new Semaphore(1);
197	<	try {
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	<	s.acquire();
207	<	s.release();
208	<	assertEquals(1, s.availablePermits());
209	<	} catch( InterruptedException e){
210	<	unexpectedException();
195	>	public void testTryAcquire_timeout() throws InterruptedException {
196	>	final boolean fair = randomBoolean();
197	>	final Semaphore s = new Semaphore(0, fair);
198	>	final long startTime = System.nanoTime();
199	>	assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS));
200	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
201	>	}
202	>
203	>	/**
204	>	* timed tryAcquire(N) times out
205	>	*/
206	>	public void testTryAcquireN_timeout() throws InterruptedException {
207	>	final boolean fair = randomBoolean();
208	>	final Semaphore s = new Semaphore(2, fair);
209	>	final long startTime = System.nanoTime();
210	>	assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS));
211	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
212	>	}
213	>
214	>	/**
215	>	* acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
216	>	* are interruptible
217	>	*/
218	>	public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
219	>	public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
220	>	public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
221	>	public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
222	>	public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
223	>	public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
224	>	public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
225	>	public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
226	>	public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
227	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
228	>	final java.util.concurrent.CyclicBarrier pleaseInterrupt
229	>	= new java.util.concurrent.CyclicBarrier(2);
230	>	Thread t = newStartedThread(new CheckedRunnable() {
231	>	public void realRun() {
232	>	// Interrupt before acquire
233	>	Thread.currentThread().interrupt();
234	>	try {
235	>	acquirer.acquire(s);
236	>	shouldThrow();
237	>	} catch (InterruptedException success) {}
238	>	assertFalse(Thread.interrupted());
239	>
240	>	// Interrupt before acquire(N)
241	>	Thread.currentThread().interrupt();
242	>	try {
243	>	acquirer.acquire(s, 3);
244	>	shouldThrow();
245	>	} catch (InterruptedException success) {}
246	>	assertFalse(Thread.interrupted());
247	>
248	>	// Interrupt during acquire
249	>	await(pleaseInterrupt);
250	>	try {
251	>	acquirer.acquire(s);
252	>	shouldThrow();
253	>	} catch (InterruptedException success) {}
254	>	assertFalse(Thread.interrupted());
255	>
256	>	// Interrupt during acquire(N)
257	>	await(pleaseInterrupt);
258	>	try {
259	>	acquirer.acquire(s, 3);
260	>	shouldThrow();
261	>	} catch (InterruptedException success) {}
262	>	assertFalse(Thread.interrupted());
263	>	}});
264	>
265	>	for (int n = 2; n-->0; ) {
266	>	await(pleaseInterrupt);
267	>	assertThreadBlocks(t, acquirer.parkedState());
268	>	t.interrupt();
269		}
270	+
271	+	awaitTermination(t);
272		}
273
274		/**
275	<	* Uninterruptible acquire and release of semaphore succeed if
276	<	* initially available
275	>	* acquireUninterruptibly(), acquireUninterruptibly(N) are
276	>	* uninterruptible
277		*/
278	<	public void testAcquireUninterruptiblyReleaseInSameThread() {
279	<	Semaphore s = new Semaphore(1);
280	<	try {
281	<	s.acquireUninterruptibly();
282	<	s.release();
283	<	s.acquireUninterruptibly();
284	<	s.release();
285	<	s.acquireUninterruptibly();
286	<	s.release();
287	<	s.acquireUninterruptibly();
288	<	s.release();
289	<	s.acquireUninterruptibly();
290	<	s.release();
291	<	assertEquals(1, s.availablePermits());
292	<	} finally {
293	<	}
278	>	public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
279	>	public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
280	>	public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
281	>	public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
282	>	public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
283	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
284	>	final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
285	>
286	>	Thread t1 = newStartedThread(new CheckedRunnable() {
287	>	public void realRun() throws InterruptedException {
288	>	// Interrupt before acquire
289	>	pleaseInterrupt.release();
290	>	Thread.currentThread().interrupt();
291	>	acquirer.acquire(s);
292	>	assertTrue(Thread.interrupted());
293	>	}});
294	>
295	>	Thread t2 = newStartedThread(new CheckedRunnable() {
296	>	public void realRun() throws InterruptedException {
297	>	// Interrupt during acquire
298	>	pleaseInterrupt.release();
299	>	acquirer.acquire(s);
300	>	assertTrue(Thread.interrupted());
301	>	}});
302	>
303	>	await(pleaseInterrupt);
304	>	waitForQueuedThread(s, t1);
305	>	waitForQueuedThread(s, t2);
306	>	t2.interrupt();
307	>
308	>	assertThreadBlocks(t1, Thread.State.WAITING);
309	>	assertThreadBlocks(t2, Thread.State.WAITING);
310	>
311	>	s.release(2);
312	>
313	>	awaitTermination(t1);
314	>	awaitTermination(t2);
315	>	}
316	>
317	>	/**
318	>	* hasQueuedThreads reports whether there are waiting threads
319	>	*/
320	>	public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
321	>	public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
322	>	public void testHasQueuedThreads(boolean fair) {
323	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
324	>	assertFalse(lock.hasQueuedThreads());
325	>	lock.acquireUninterruptibly();
326	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
327	>	waitForQueuedThread(lock, t1);
328	>	assertTrue(lock.hasQueuedThreads());
329	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
330	>	waitForQueuedThread(lock, t2);
331	>	assertTrue(lock.hasQueuedThreads());
332	>	t1.interrupt();
333	>	awaitTermination(t1);
334	>	assertTrue(lock.hasQueuedThreads());
335	>	lock.release();
336	>	awaitTermination(t2);
337	>	assertFalse(lock.hasQueuedThreads());
338	>	}
339	>
340	>	/**
341	>	* getQueueLength reports number of waiting threads
342	>	*/
343	>	public void testGetQueueLength()      { testGetQueueLength(false); }
344	>	public void testGetQueueLength_fair() { testGetQueueLength(true); }
345	>	public void testGetQueueLength(boolean fair) {
346	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
347	>	assertEquals(0, lock.getQueueLength());
348	>	lock.acquireUninterruptibly();
349	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
350	>	waitForQueuedThread(lock, t1);
351	>	assertEquals(1, lock.getQueueLength());
352	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
353	>	waitForQueuedThread(lock, t2);
354	>	assertEquals(2, lock.getQueueLength());
355	>	t1.interrupt();
356	>	awaitTermination(t1);
357	>	assertEquals(1, lock.getQueueLength());
358	>	lock.release();
359	>	awaitTermination(t2);
360	>	assertEquals(0, lock.getQueueLength());
361	>	}
362	>
363	>	/**
364	>	* getQueuedThreads includes waiting threads
365	>	*/
366	>	public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
367	>	public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
368	>	public void testGetQueuedThreads(boolean fair) {
369	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
370	>	assertTrue(lock.getQueuedThreads().isEmpty());
371	>	lock.acquireUninterruptibly();
372	>	assertTrue(lock.getQueuedThreads().isEmpty());
373	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
374	>	waitForQueuedThread(lock, t1);
375	>	assertTrue(lock.getQueuedThreads().contains(t1));
376	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
377	>	waitForQueuedThread(lock, t2);
378	>	assertTrue(lock.getQueuedThreads().contains(t1));
379	>	assertTrue(lock.getQueuedThreads().contains(t2));
380	>	t1.interrupt();
381	>	awaitTermination(t1);
382	>	assertFalse(lock.getQueuedThreads().contains(t1));
383	>	assertTrue(lock.getQueuedThreads().contains(t2));
384	>	lock.release();
385	>	awaitTermination(t2);
386	>	assertTrue(lock.getQueuedThreads().isEmpty());
387	>	}
388	>
389	>	/**
390	>	* drainPermits reports and removes given number of permits
391	>	*/
392	>	public void testDrainPermits()      { testDrainPermits(false); }
393	>	public void testDrainPermits_fair() { testDrainPermits(true); }
394	>	public void testDrainPermits(boolean fair) {
395	>	Semaphore s = new Semaphore(0, fair);
396	>	assertEquals(0, s.availablePermits());
397	>	assertEquals(0, s.drainPermits());
398	>	s.release(10);
399	>	assertEquals(10, s.availablePermits());
400	>	assertEquals(10, s.drainPermits());
401	>	assertEquals(0, s.availablePermits());
402	>	assertEquals(0, s.drainPermits());
403		}
404
405		/**
406	<	* Timed Acquire and release of semaphore succeed if
91	<	* initially available
406	>	* release(-N) throws IllegalArgumentException
407		*/
408	<	public void testTimedAcquireReleaseInSameThread() {
409	<	Semaphore s = new Semaphore(1);
408	>	public void testReleaseIAE()      { testReleaseIAE(false); }
409	>	public void testReleaseIAE_fair() { testReleaseIAE(true); }
410	>	public void testReleaseIAE(boolean fair) {
411	>	Semaphore s = new Semaphore(10, fair);
412		try {
413	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
414	<	s.release();
415	<	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	<	}
413	>	s.release(-1);
414	>	shouldThrow();
415	>	} catch (IllegalArgumentException success) {}
416		}
417
418		/**
419	<	* A release in one thread enables an acquire in another thread
419	>	* reducePermits(-N) throws IllegalArgumentException
420		*/
421	<	public void testAcquireReleaseInDifferentThreads() {
422	<	final Semaphore s = new Semaphore(0);
423	<	Thread t = new Thread(new Runnable() {
424	<	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	<	});
421	>	public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
422	>	public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
423	>	public void testReducePermitsIAE(boolean fair) {
424	>	PublicSemaphore s = new PublicSemaphore(10, fair);
425		try {
426	<	t.start();
427	<	Thread.sleep(SHORT_DELAY_MS);
428	<	s.release();
429	<	s.release();
426	>	s.reducePermits(-1);
427	>	shouldThrow();
428	>	} catch (IllegalArgumentException success) {}
429	>	}
430	>
431	>	/**
432	>	* reducePermits reduces number of permits
433	>	*/
434	>	public void testReducePermits()      { testReducePermits(false); }
435	>	public void testReducePermits_fair() { testReducePermits(true); }
436	>	public void testReducePermits(boolean fair) {
437	>	PublicSemaphore s = new PublicSemaphore(10, fair);
438	>	assertEquals(10, s.availablePermits());
439	>	s.reducePermits(0);
440	>	assertEquals(10, s.availablePermits());
441	>	s.reducePermits(1);
442	>	assertEquals(9, s.availablePermits());
443	>	s.reducePermits(10);
444	>	assertEquals(-1, s.availablePermits());
445	>	s.reducePermits(10);
446	>	assertEquals(-11, s.availablePermits());
447	>	s.reducePermits(0);
448	>	assertEquals(-11, s.availablePermits());
449	>	}
450	>
451	>	/**
452	>	* a reserialized semaphore has same number of permits and
453	>	* fairness, but no queued threads
454	>	*/
455	>	public void testSerialization()      { testSerialization(false); }
456	>	public void testSerialization_fair() { testSerialization(true); }
457	>	public void testSerialization(boolean fair) {
458	>	try {
459	>	Semaphore s = new Semaphore(3, fair);
460		s.acquire();
461		s.acquire();
462		s.release();
463	<	t.join();
464	<	} catch( InterruptedException e){
465	<	unexpectedException();
463	>
464	>	Semaphore clone = serialClone(s);
465	>	assertEquals(fair, s.isFair());
466	>	assertEquals(fair, clone.isFair());
467	>	assertEquals(2, s.availablePermits());
468	>	assertEquals(2, clone.availablePermits());
469	>	clone.acquire();
470	>	clone.acquire();
471	>	clone.release();
472	>	assertEquals(2, s.availablePermits());
473	>	assertEquals(1, clone.availablePermits());
474	>	assertFalse(s.hasQueuedThreads());
475	>	assertFalse(clone.hasQueuedThreads());
476	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
477	>
478	>	{
479	>	PublicSemaphore s = new PublicSemaphore(0, fair);
480	>	Thread t = newStartedThread(new InterruptibleLockRunnable(s));
481	>	// waitForQueuedThreads(s); // suffers from "flicker", so ...
482	>	waitForQueuedThread(s, t);  // ... we use this instead
483	>	PublicSemaphore clone = serialClone(s);
484	>	assertEquals(fair, s.isFair());
485	>	assertEquals(fair, clone.isFair());
486	>	assertEquals(0, s.availablePermits());
487	>	assertEquals(0, clone.availablePermits());
488	>	assertTrue(s.hasQueuedThreads());
489	>	assertFalse(clone.hasQueuedThreads());
490	>	s.release();
491	>	awaitTermination(t);
492	>	assertFalse(s.hasQueuedThreads());
493	>	assertFalse(clone.hasQueuedThreads());
494		}
495		}
496
497		/**
498	<	* A release in one thread enables an uninterruptible acquire in another thread
498	>	* tryAcquire(n) succeeds when sufficient permits, else fails
499		*/
500	<	public void testUninterruptibleAcquireReleaseInDifferentThreads() {
501	<	final Semaphore s = new Semaphore(0);
502	<	Thread t = new Thread(new Runnable() {
503	<	public void run() {
504	<	s.acquireUninterruptibly();
505	<	s.release();
506	<	s.release();
507	<	s.acquireUninterruptibly();
508	<	}
509	<	});
510	<	try {
511	<	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	<	}
500	>	public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
501	>	public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
502	>	public void testTryAcquireNInSameThread(boolean fair) {
503	>	Semaphore s = new Semaphore(2, fair);
504	>	assertEquals(2, s.availablePermits());
505	>	assertFalse(s.tryAcquire(3));
506	>	assertEquals(2, s.availablePermits());
507	>	assertTrue(s.tryAcquire(2));
508	>	assertEquals(0, s.availablePermits());
509	>	assertFalse(s.tryAcquire(1));
510	>	assertFalse(s.tryAcquire(2));
511	>	assertEquals(0, s.availablePermits());
512		}
513
170	–
514		/**
515	<	*  A release in one thread enables a timed acquire in another thread
515	>	* acquire succeeds if permits available
516		*/
517	<	public void testTimedAcquireReleaseInDifferentThreads() {
518	<	final Semaphore s = new Semaphore(1);
519	<	Thread t = new Thread(new Runnable() {
520	<	public void run() {
521	<	try {
522	<	s.release();
523	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
524	<	s.release();
525	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
526	<
527	<	} catch(InterruptedException ie){
528	<	threadUnexpectedException();
529	<	}
530	<	}
531	<	});
532	<	try {
533	<	t.start();
534	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
535	<	s.release();
536	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
537	<	s.release();
538	<	s.release();
539	<	t.join();
540	<	} catch( InterruptedException e){
541	<	unexpectedException();
517	>	public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
518	>	public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
519	>	public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
520	>	public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
521	>	public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
522	>	public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
523	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
524	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
525	>	public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
526	>	public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
527	>	public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
528	>	public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
529	>	public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
530	>	public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
531	>	public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
532	>	public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
533	>	public void testReleaseAcquireSameThread(boolean fair,
534	>	final AcquireMethod acquirer) {
535	>	Semaphore s = new Semaphore(1, fair);
536	>	for (int i = 1; i < 6; i++) {
537	>	s.release(i);
538	>	assertEquals(1 + i, s.availablePermits());
539	>	try {
540	>	acquirer.acquire(s, i);
541	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
542	>	assertEquals(1, s.availablePermits());
543		}
544		}
545
546		/**
547	<	* A waiting acquire blocks interruptibly
548	<	*/
549	<	public void testAcquire_InterruptedException() {
550	<	final Semaphore s = new Semaphore(0);
551	<	Thread t = new Thread(new Runnable() {
552	<	public void run() {
553	<	try {
554	<	s.acquire();
555	<	threadShouldThrow();
556	<	} catch(InterruptedException success){}
557	<	}
558	<	});
559	<	t.start();
560	<	try {
561	<	Thread.sleep(SHORT_DELAY_MS);
562	<	t.interrupt();
563	<	t.join();
564	<	} catch(InterruptedException e){
565	<	unexpectedException();
566	<	}
567	<	}
568	<
569	<	/**
570	<	*  A waiting timed acquire blocks interruptibly
571	<	*/
572	<	public void testTryAcquire_InterruptedException() {
573	<	final Semaphore s = new Semaphore(0);
574	<	Thread t = new Thread(new Runnable() {
575	<	public void run() {
576	<	try {
577	<	s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
578	<	threadShouldThrow();
579	<	} catch(InterruptedException success){
580	<	}
581	<	}
582	<	});
583	<	t.start();
240	<	try {
241	<	Thread.sleep(SHORT_DELAY_MS);
242	<	t.interrupt();
243	<	t.join();
244	<	} catch(InterruptedException e){
245	<	unexpectedException();
547	>	* release in one thread enables acquire in another thread
548	>	*/
549	>	public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
550	>	public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
551	>	public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
552	>	public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
553	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
554	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
555	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
556	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
557	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
558	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
559	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
560	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
561	>	public void testReleaseAcquireDifferentThreads(boolean fair,
562	>	final AcquireMethod acquirer) {
563	>	final Semaphore s = new Semaphore(0, fair);
564	>	final int rounds = 4;
565	>	long startTime = System.nanoTime();
566	>	Thread t = newStartedThread(new CheckedRunnable() {
567	>	public void realRun() throws InterruptedException {
568	>	for (int i = 0; i < rounds; i++) {
569	>	assertFalse(s.hasQueuedThreads());
570	>	if (i % 2 == 0)
571	>	acquirer.acquire(s);
572	>	else
573	>	acquirer.acquire(s, 3);
574	>	}}});
575	>
576	>	for (int i = 0; i < rounds; i++) {
577	>	while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
578	>	Thread.yield();
579	>	assertTrue(t.isAlive());
580	>	if (i % 2 == 0)
581	>	s.release();
582	>	else
583	>	s.release(3);
584		}
585	+	awaitTermination(t);
586	+	assertEquals(0, s.availablePermits());
587	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
588		}
589
590		/**
591	<	* a deserialized serialized semaphore has same number of permits
591	>	* fair locks are strictly FIFO
592		*/
593	<	public void testSerialization() {
594	<	Semaphore l = new Semaphore(3);
595	<	try {
596	<	l.acquire();
597	<	l.release();
598	<	ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
599	<	ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
600	<	out.writeObject(l);
601	<	out.close();
602	<
603	<	ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
604	<	ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
605	<	Semaphore r = (Semaphore) in.readObject();
606	<	assertEquals(3, r.availablePermits());
607	<	r.acquire();
608	<	r.release();
609	<	} catch(Exception e){
610	<	unexpectedException();
611	<	}
593	>	public void testFairLocksFifo() {
594	>	final PublicSemaphore s = new PublicSemaphore(1, true);
595	>	final CountDownLatch pleaseRelease = new CountDownLatch(1);
596	>	Thread t1 = newStartedThread(new CheckedRunnable() {
597	>	public void realRun() throws InterruptedException {
598	>	// Will block; permits are available, but not three
599	>	s.acquire(3);
600	>	}});
601	>
602	>	waitForQueuedThread(s, t1);
603	>
604	>	Thread t2 = newStartedThread(new CheckedRunnable() {
605	>	public void realRun() throws InterruptedException {
606	>	// Will fail, even though 1 permit is available
607	>	assertFalse(
608	>	s.tryAcquire(randomExpiredTimeout(), randomTimeUnit()));
609	>	assertFalse(
610	>	s.tryAcquire(1, randomExpiredTimeout(), randomTimeUnit()));
611	>
612	>	// untimed tryAcquire will barge and succeed
613	>	assertTrue(s.tryAcquire());
614	>	s.release(2);
615	>	assertTrue(s.tryAcquire(2));
616	>	s.release();
617	>
618	>	pleaseRelease.countDown();
619	>	// Will queue up behind t1, even though 1 permit is available
620	>	s.acquire();
621	>	}});
622	>
623	>	await(pleaseRelease);
624	>	waitForQueuedThread(s, t2);
625	>	s.release(2);
626	>	awaitTermination(t1);
627	>	assertTrue(t2.isAlive());
628	>	s.release();
629	>	awaitTermination(t2);
630	>	}
631	>
632	>	/**
633	>	* toString indicates current number of permits
634	>	*/
635	>	public void testToString()      { testToString(false); }
636	>	public void testToString_fair() { testToString(true); }
637	>	public void testToString(boolean fair) {
638	>	PublicSemaphore s = new PublicSemaphore(0, fair);
639	>	assertTrue(s.toString().contains("Permits = 0"));
640	>	s.release();
641	>	assertTrue(s.toString().contains("Permits = 1"));
642	>	s.release(2);
643	>	assertTrue(s.toString().contains("Permits = 3"));
644	>	s.reducePermits(5);
645	>	assertTrue(s.toString().contains("Permits = -2"));
646		}
647
648		}

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