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

Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.3 by dl, Sun Sep 14 20:42:40 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.*;
9	<	import java.util.*;
10	<	import java.util.concurrent.*;
11	<	import java.io.*;
9	>	import static java.util.concurrent.TimeUnit.MILLISECONDS;
10
11	<	public class SemaphoreTest extends JSR166TestCase {
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		}
18	–
24		public static Test suite() {
25	<	return new TestSuite(SemaphoreTest.class);
25	>	return new TestSuite(SemaphoreTest.class);
26		}
27
28	<	public void testConstructor1() {
29	<	Semaphore s = new Semaphore(0);
30	<	assertEquals(0, s.availablePermits());
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	<	public void testConstructor2() {
46	<	Semaphore s = new Semaphore(-1);
47	<	assertEquals(-1, s.availablePermits());
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	<	public void testTryAcquireInSameThread() {
155	<	Semaphore s = new Semaphore(2);
154	>	/**
155	>	* Zero, negative, and positive initial values are allowed in constructor
156	>	*/
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	>	* Constructor without fairness argument behaves as nonfair
169	>	*/
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	<	public void testAcquireReleaseInSameThread(){
195	<	Semaphore s = new Semaphore(1);
196	<	try {
197	<	s.acquire();
198	<	s.release();
199	<	s.acquire();
200	<	s.release();
201	<	s.acquire();
202	<	s.release();
203	<	s.acquire();
204	<	s.release();
205	<	s.acquire();
206	<	s.release();
207	<	assertEquals(1, s.availablePermits());
208	<	} catch( InterruptedException e){
209	<	fail("unexpected exception");
194	>	/**
195	>	* timed tryAcquire times out
196	>	*/
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	+	* acquireUninterruptibly(), acquireUninterruptibly(N) are
282	+	* uninterruptible
283	+	*/
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	<	public void testAcquireUninterruptiblyReleaseInSameThread(){
412	<	Semaphore s = new Semaphore(1);
411	>	/**
412	>	* release(-N) throws IllegalArgumentException
413	>	*/
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	<	s.acquireUninterruptibly();
420	<	s.release();
421	<	s.acquireUninterruptibly();
67	<	s.release();
68	<	s.acquireUninterruptibly();
69	<	s.release();
70	<	s.acquireUninterruptibly();
71	<	s.release();
72	<	s.acquireUninterruptibly();
73	<	s.release();
74	<	assertEquals(1, s.availablePermits());
75	<	} finally {
76	<	}
419	>	s.release(-1);
420	>	shouldThrow();
421	>	} catch (IllegalArgumentException success) {}
422		}
423
424	+	/**
425	+	* reducePermits(-N) throws IllegalArgumentException
426	+	*/
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	+	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	<	public void testAcquireReleaseInDifferentThreads() {
458	<	final Semaphore s = new Semaphore(1);
459	<	Thread t = new Thread(new Runnable(){
460	<	public void run(){
461	<	try{
462	<	s.acquire();
463	<	s.release();
87	<	s.release();
88	<	s.acquire();
89	<	}catch(InterruptedException ie){
90	<	threadFail("unexpected exception");
91	<	}
92	<	}
93	<	});
94	<	t.start();
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	<	s.release();
97	<	s.release();
465	>	Semaphore s = new Semaphore(3, fair);
466		s.acquire();
467		s.acquire();
468	<	t.join();
469	<	} catch( InterruptedException e){
470	<	fail("unexpected exception");
468	>	s.release();
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	<	public void testTimedAcquireReleaseInSameThread(){
504	<	Semaphore s = new Semaphore(1);
505	<	try {
506	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
507	<	s.release();
508	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
509	<	s.release();
510	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
511	<	s.release();
512	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
513	<	s.release();
514	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
515	<	s.release();
516	<	assertEquals(1, s.availablePermits());
517	<	} catch( InterruptedException e){
121	<	fail("unexpected exception");
122	<	}
503	>	/**
504	>	* tryAcquire(n) succeeds when sufficient permits, else fails
505	>	*/
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
520	<	public void testTimedAcquireReleaseInDifferentThreads() {
521	<	final Semaphore s = new Semaphore(1);
522	<	Thread t = new Thread(new Runnable(){
523	<	public void run(){
524	<	try{
525	<	s.release();
526	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
527	<	s.release();
528	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
529	<
530	<	}catch(InterruptedException ie){
531	<	threadFail("unexpected exception");
532	<	}
533	<	}
534	<	});
535	<	t.start();
536	<	try {
537	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
538	<	s.release();
539	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
540	<	s.release();
541	<	t.join();
542	<	} catch( InterruptedException e){
543	<	fail("unexpected exception");
520	>	/**
521	>	* acquire succeeds if permits available
522	>	*/
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	<	public void testAcquire_InterruptedException(){
553	<	final Semaphore s = new Semaphore(0);
554	<	Thread t = new Thread(new Runnable(){
555	<	public void run(){
556	<	try{
557	<	s.acquire();
558	<	threadFail("should throw");
559	<	}catch(InterruptedException success){}
560	<	}
561	<	});
562	<	t.start();
563	<	try{
564	<	Thread.sleep(SHORT_DELAY_MS);
565	<	t.interrupt();
566	<	t.join();
567	<	} catch(InterruptedException e){
568	<	fail("unexpected exception");
569	<	}
570	<	}
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	<	threadFail("should throw");
579	<	}catch(InterruptedException success){
580	<	}
581	<	}
582	<	});
583	<	t.start();
584	<	try{
585	<	Thread.sleep(SHORT_DELAY_MS);
586	<	t.interrupt();
587	<	t.join();
588	<	} catch(InterruptedException e){
589	<	fail("unexpected exception");
552	>	/**
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	<	public void testSerialization() {
597	<	Semaphore l = new Semaphore(3);
598	<	try {
599	<	l.acquire();
600	<	l.release();
601	<	ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
602	<	ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
603	<	out.writeObject(l);
604	<	out.close();
605	<
606	<	ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
607	<	ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
608	<	Semaphore r = (Semaphore) in.readObject();
609	<	assertEquals(3, r.availablePermits());
610	<	r.acquire();
611	<	r.release();
612	<	} catch(Exception e){
613	<	e.printStackTrace();
614	<	fail("unexpected exception");
615	<	}
596	>	/**
597	>	* fair locks are strictly FIFO
598	>	*/
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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