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

Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.1 by dl, Sun Aug 31 19:24:55 2003 UTC vs.
Revision 1.44 by jsr166, Mon Aug 12 06:21:11 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.*;
9	<	import java.util.*;
10	<	import java.util.concurrent.*;
9	>	import static java.util.concurrent.TimeUnit.MILLISECONDS;
10
11	<	public class SemaphoreTest extends TestCase{
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.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		}
17	–
23		public static Test suite() {
24	<	return new TestSuite(SemaphoreTest.class);
24	>	return new TestSuite(SemaphoreTest.class);
25		}
26
27	<	private static long SHORT_DELAY_MS = 100;
28	<	private static long MEDIUM_DELAY_MS = 1000;
29	<	private static long LONG_DELAY_MS = 10000;
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	<	public void testConstructor1() {
59	<	Semaphore s = new Semaphore(0);
60	<	assertEquals(0, s.availablePermits());
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	<	public void testConstructor2() {
70	<	Semaphore s = new Semaphore(-1);
71	<	assertEquals(-1, s.availablePermits());
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 AssertionError("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 AssertionError("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	>	Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
131	>	},
132	>	tryAcquireTimedN {
133	>	void acquire(Semaphore s, int permits) throws InterruptedException {
134	>	assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS));
135	>	}
136	>	Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
137	>	};
138	>
139	>	// Intentionally meta-circular
140	>
141	>	/** Acquires 1 permit. */
142	>	void acquire(Semaphore s) throws InterruptedException {
143	>	acquire(s, 1);
144	>	}
145	>	/** Acquires the given number of permits. */
146	>	void acquire(Semaphore s, int permits) throws InterruptedException {
147	>	for (int i = 0; i < permits; i++)
148	>	acquire(s);
149	>	}
150	>	Thread.State parkedState() { return Thread.State.WAITING; }
151		}
152
153	<	public void testTryAcquireInSameThread() {
154	<	Semaphore s = new Semaphore(2);
153	>	/**
154	>	* Zero, negative, and positive initial values are allowed in constructor
155	>	*/
156	>	public void testConstructor()      { testConstructor(false); }
157	>	public void testConstructor_fair() { testConstructor(true); }
158	>	public void testConstructor(boolean fair) {
159	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
160	>	Semaphore s = new Semaphore(permits, fair);
161	>	assertEquals(permits, s.availablePermits());
162	>	assertEquals(fair, s.isFair());
163	>	}
164	>	}
165	>
166	>	/**
167	>	* Constructor without fairness argument behaves as nonfair
168	>	*/
169	>	public void testConstructorDefaultsToNonFair() {
170	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
171	>	Semaphore s = new Semaphore(permits);
172	>	assertEquals(permits, s.availablePermits());
173	>	assertFalse(s.isFair());
174	>	}
175	>	}
176	>
177	>	/**
178	>	* tryAcquire succeeds when sufficient permits, else fails
179	>	*/
180	>	public void testTryAcquireInSameThread()      { testTryAcquireInSameThread(false); }
181	>	public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); }
182	>	public void testTryAcquireInSameThread(boolean fair) {
183	>	Semaphore s = new Semaphore(2, fair);
184		assertEquals(2, s.availablePermits());
185		assertTrue(s.tryAcquire());
186		assertTrue(s.tryAcquire());
187		assertEquals(0, s.availablePermits());
188		assertFalse(s.tryAcquire());
189	+	assertFalse(s.tryAcquire());
190	+	assertEquals(0, s.availablePermits());
191		}
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	<	fail("unexpected exception");
193	>	/**
194	>	* timed tryAcquire times out
195	>	*/
196	>	public void testTryAcquire_timeout() throws InterruptedException {
197	>	final boolean fair = randomBoolean();
198	>	final Semaphore s = new Semaphore(0, fair);
199	>	final long startTime = System.nanoTime();
200	>	assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS));
201	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
202	>	}
203	>
204	>	/**
205	>	* timed tryAcquire(N) times out
206	>	*/
207	>	public void testTryAcquireN_timeout() throws InterruptedException {
208	>	final boolean fair = randomBoolean();
209	>	final Semaphore s = new Semaphore(2, fair);
210	>	final long startTime = System.nanoTime();
211	>	assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS));
212	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
213	>	}
214	>
215	>	/**
216	>	* acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
217	>	* are interruptible
218	>	*/
219	>	public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
220	>	public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
221	>	public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
222	>	public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
223	>	public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
224	>	public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
225	>	public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
226	>	public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
227	>	public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
228	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
229	>	final java.util.concurrent.CyclicBarrier pleaseInterrupt
230	>	= new java.util.concurrent.CyclicBarrier(2);
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	>	assertFalse(Thread.interrupted());
240	>
241	>	// Interrupt before acquire(N)
242	>	Thread.currentThread().interrupt();
243	>	try {
244	>	acquirer.acquire(s, 3);
245	>	shouldThrow();
246	>	} catch (InterruptedException success) {}
247	>	assertFalse(Thread.interrupted());
248	>
249	>	// Interrupt during acquire
250	>	await(pleaseInterrupt);
251	>	try {
252	>	acquirer.acquire(s);
253	>	shouldThrow();
254	>	} catch (InterruptedException success) {}
255	>	assertFalse(Thread.interrupted());
256	>
257	>	// Interrupt during acquire(N)
258	>	await(pleaseInterrupt);
259	>	try {
260	>	acquirer.acquire(s, 3);
261	>	shouldThrow();
262	>	} catch (InterruptedException success) {}
263	>	assertFalse(Thread.interrupted());
264	>	}});
265	>
266	>	for (int n = 2; n-->0; ) {
267	>	await(pleaseInterrupt);
268	>	assertThreadBlocks(t, acquirer.parkedState());
269	>	t.interrupt();
270		}
271	+
272	+	awaitTermination(t);
273	+	}
274	+
275	+	/**
276	+	* acquireUninterruptibly(), acquireUninterruptibly(N) are
277	+	* uninterruptible
278	+	*/
279	+	public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
280	+	public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
281	+	public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
282	+	public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
283	+	public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
284	+	final PublicSemaphore s = new PublicSemaphore(0, fair);
285	+	final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
286	+
287	+	Thread t1 = newStartedThread(new CheckedRunnable() {
288	+	public void realRun() throws InterruptedException {
289	+	// Interrupt before acquire
290	+	pleaseInterrupt.release();
291	+	Thread.currentThread().interrupt();
292	+	acquirer.acquire(s);
293	+	assertTrue(Thread.interrupted());
294	+	}});
295	+
296	+	Thread t2 = newStartedThread(new CheckedRunnable() {
297	+	public void realRun() throws InterruptedException {
298	+	// Interrupt during acquire
299	+	pleaseInterrupt.release();
300	+	acquirer.acquire(s);
301	+	assertTrue(Thread.interrupted());
302	+	}});
303	+
304	+	await(pleaseInterrupt);
305	+	waitForQueuedThread(s, t1);
306	+	waitForQueuedThread(s, t2);
307	+	t2.interrupt();
308	+
309	+	assertThreadBlocks(t1, Thread.State.WAITING);
310	+	assertThreadBlocks(t2, Thread.State.WAITING);
311	+
312	+	s.release(2);
313	+
314	+	awaitTermination(t1);
315	+	awaitTermination(t2);
316	+	}
317	+
318	+	/**
319	+	* hasQueuedThreads reports whether there are waiting threads
320	+	*/
321	+	public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
322	+	public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
323	+	public void testHasQueuedThreads(boolean fair) {
324	+	final PublicSemaphore lock = new PublicSemaphore(1, fair);
325	+	assertFalse(lock.hasQueuedThreads());
326	+	lock.acquireUninterruptibly();
327	+	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
328	+	waitForQueuedThread(lock, t1);
329	+	assertTrue(lock.hasQueuedThreads());
330	+	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
331	+	waitForQueuedThread(lock, t2);
332	+	assertTrue(lock.hasQueuedThreads());
333	+	t1.interrupt();
334	+	awaitTermination(t1);
335	+	assertTrue(lock.hasQueuedThreads());
336	+	lock.release();
337	+	awaitTermination(t2);
338	+	assertFalse(lock.hasQueuedThreads());
339	+	}
340	+
341	+	/**
342	+	* getQueueLength reports number of waiting threads
343	+	*/
344	+	public void testGetQueueLength()      { testGetQueueLength(false); }
345	+	public void testGetQueueLength_fair() { testGetQueueLength(true); }
346	+	public void testGetQueueLength(boolean fair) {
347	+	final PublicSemaphore lock = new PublicSemaphore(1, fair);
348	+	assertEquals(0, lock.getQueueLength());
349	+	lock.acquireUninterruptibly();
350	+	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
351	+	waitForQueuedThread(lock, t1);
352	+	assertEquals(1, lock.getQueueLength());
353	+	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
354	+	waitForQueuedThread(lock, t2);
355	+	assertEquals(2, lock.getQueueLength());
356	+	t1.interrupt();
357	+	awaitTermination(t1);
358	+	assertEquals(1, lock.getQueueLength());
359	+	lock.release();
360	+	awaitTermination(t2);
361	+	assertEquals(0, lock.getQueueLength());
362	+	}
363	+
364	+	/**
365	+	* getQueuedThreads includes waiting threads
366	+	*/
367	+	public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
368	+	public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
369	+	public void testGetQueuedThreads(boolean fair) {
370	+	final PublicSemaphore lock = new PublicSemaphore(1, fair);
371	+	assertTrue(lock.getQueuedThreads().isEmpty());
372	+	lock.acquireUninterruptibly();
373	+	assertTrue(lock.getQueuedThreads().isEmpty());
374	+	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
375	+	waitForQueuedThread(lock, t1);
376	+	assertTrue(lock.getQueuedThreads().contains(t1));
377	+	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
378	+	waitForQueuedThread(lock, t2);
379	+	assertTrue(lock.getQueuedThreads().contains(t1));
380	+	assertTrue(lock.getQueuedThreads().contains(t2));
381	+	t1.interrupt();
382	+	awaitTermination(t1);
383	+	assertFalse(lock.getQueuedThreads().contains(t1));
384	+	assertTrue(lock.getQueuedThreads().contains(t2));
385	+	lock.release();
386	+	awaitTermination(t2);
387	+	assertTrue(lock.getQueuedThreads().isEmpty());
388	+	}
389	+
390	+	/**
391	+	* drainPermits reports and removes given number of permits
392	+	*/
393	+	public void testDrainPermits()      { testDrainPermits(false); }
394	+	public void testDrainPermits_fair() { testDrainPermits(true); }
395	+	public void testDrainPermits(boolean fair) {
396	+	Semaphore s = new Semaphore(0, fair);
397	+	assertEquals(0, s.availablePermits());
398	+	assertEquals(0, s.drainPermits());
399	+	s.release(10);
400	+	assertEquals(10, s.availablePermits());
401	+	assertEquals(10, s.drainPermits());
402	+	assertEquals(0, s.availablePermits());
403	+	assertEquals(0, s.drainPermits());
404		}
405
406	<	public void testAcquireUninterruptiblyReleaseInSameThread(){
407	<	Semaphore s = new Semaphore(1);
406	>	/**
407	>	* release(-N) throws IllegalArgumentException
408	>	*/
409	>	public void testReleaseIAE()      { testReleaseIAE(false); }
410	>	public void testReleaseIAE_fair() { testReleaseIAE(true); }
411	>	public void testReleaseIAE(boolean fair) {
412	>	Semaphore s = new Semaphore(10, fair);
413		try {
414	<	s.acquireUninterruptibly();
415	<	s.release();
416	<	s.acquireUninterruptibly();
71	<	s.release();
72	<	s.acquireUninterruptibly();
73	<	s.release();
74	<	s.acquireUninterruptibly();
75	<	s.release();
76	<	s.acquireUninterruptibly();
77	<	s.release();
78	<	assertEquals(1, s.availablePermits());
79	<	} finally {
80	<	}
414	>	s.release(-1);
415	>	shouldThrow();
416	>	} catch (IllegalArgumentException success) {}
417		}
418
419	+	/**
420	+	* reducePermits(-N) throws IllegalArgumentException
421	+	*/
422	+	public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
423	+	public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
424	+	public void testReducePermitsIAE(boolean fair) {
425	+	PublicSemaphore s = new PublicSemaphore(10, fair);
426	+	try {
427	+	s.reducePermits(-1);
428	+	shouldThrow();
429	+	} catch (IllegalArgumentException success) {}
430	+	}
431	+
432	+	/**
433	+	* reducePermits reduces number of permits
434	+	*/
435	+	public void testReducePermits()      { testReducePermits(false); }
436	+	public void testReducePermits_fair() { testReducePermits(true); }
437	+	public void testReducePermits(boolean fair) {
438	+	PublicSemaphore s = new PublicSemaphore(10, fair);
439	+	assertEquals(10, s.availablePermits());
440	+	s.reducePermits(0);
441	+	assertEquals(10, s.availablePermits());
442	+	s.reducePermits(1);
443	+	assertEquals(9, s.availablePermits());
444	+	s.reducePermits(10);
445	+	assertEquals(-1, s.availablePermits());
446	+	s.reducePermits(10);
447	+	assertEquals(-11, s.availablePermits());
448	+	s.reducePermits(0);
449	+	assertEquals(-11, s.availablePermits());
450	+	}
451
452	<	public void testAcquireReleaseInDifferentThreads() {
453	<	final Semaphore s = new Semaphore(1);
454	<	Thread t = new Thread(new Runnable(){
455	<	public void run(){
456	<	try{
457	<	s.acquire();
458	<	s.release();
91	<	s.release();
92	<	s.acquire();
93	<	}catch(InterruptedException ie){
94	<	fail("unexpected exception");
95	<	}
96	<	}
97	<	});
98	<	t.start();
452	>	/**
453	>	* a reserialized semaphore has same number of permits and
454	>	* fairness, but no queued threads
455	>	*/
456	>	public void testSerialization()      { testSerialization(false); }
457	>	public void testSerialization_fair() { testSerialization(true); }
458	>	public void testSerialization(boolean fair) {
459		try {
460	<	s.release();
101	<	s.release();
460	>	Semaphore s = new Semaphore(3, fair);
461		s.acquire();
462		s.acquire();
463	<	t.join();
464	<	} catch( InterruptedException e){
465	<	fail("unexpected exception");
463	>	s.release();
464	>
465	>	Semaphore clone = serialClone(s);
466	>	assertEquals(fair, s.isFair());
467	>	assertEquals(fair, clone.isFair());
468	>	assertEquals(2, s.availablePermits());
469	>	assertEquals(2, clone.availablePermits());
470	>	clone.acquire();
471	>	clone.acquire();
472	>	clone.release();
473	>	assertEquals(2, s.availablePermits());
474	>	assertEquals(1, clone.availablePermits());
475	>	assertFalse(s.hasQueuedThreads());
476	>	assertFalse(clone.hasQueuedThreads());
477	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
478	>
479	>	{
480	>	PublicSemaphore s = new PublicSemaphore(0, fair);
481	>	Thread t = newStartedThread(new InterruptibleLockRunnable(s));
482	>	// waitForQueuedThreads(s); // suffers from "flicker", so ...
483	>	waitForQueuedThread(s, t);  // ... we use this instead
484	>	PublicSemaphore clone = serialClone(s);
485	>	assertEquals(fair, s.isFair());
486	>	assertEquals(fair, clone.isFair());
487	>	assertEquals(0, s.availablePermits());
488	>	assertEquals(0, clone.availablePermits());
489	>	assertTrue(s.hasQueuedThreads());
490	>	assertFalse(clone.hasQueuedThreads());
491	>	s.release();
492	>	awaitTermination(t);
493	>	assertFalse(s.hasQueuedThreads());
494	>	assertFalse(clone.hasQueuedThreads());
495		}
496		}
497
498	<	public void testTimedAcquireReleaseInSameThread(){
499	<	Semaphore s = new Semaphore(1);
500	<	try {
501	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
502	<	s.release();
503	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
504	<	s.release();
505	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
506	<	s.release();
507	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
508	<	s.release();
509	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
510	<	s.release();
498	>	/**
499	>	* tryAcquire(n) succeeds when sufficient permits, else fails
500	>	*/
501	>	public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
502	>	public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
503	>	public void testTryAcquireNInSameThread(boolean fair) {
504	>	Semaphore s = new Semaphore(2, fair);
505	>	assertEquals(2, s.availablePermits());
506	>	assertFalse(s.tryAcquire(3));
507	>	assertEquals(2, s.availablePermits());
508	>	assertTrue(s.tryAcquire(2));
509	>	assertEquals(0, s.availablePermits());
510	>	assertFalse(s.tryAcquire(1));
511	>	assertFalse(s.tryAcquire(2));
512	>	assertEquals(0, s.availablePermits());
513	>	}
514	>
515	>	/**
516	>	* acquire succeeds if permits available
517	>	*/
518	>	public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
519	>	public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
520	>	public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
521	>	public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
522	>	public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
523	>	public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
524	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
525	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
526	>	public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
527	>	public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
528	>	public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
529	>	public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
530	>	public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
531	>	public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
532	>	public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
533	>	public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
534	>	public void testReleaseAcquireSameThread(boolean fair,
535	>	final AcquireMethod acquirer) {
536	>	Semaphore s = new Semaphore(1, fair);
537	>	for (int i = 1; i < 6; i++) {
538	>	s.release(i);
539	>	assertEquals(1 + i, s.availablePermits());
540	>	try {
541	>	acquirer.acquire(s, i);
542	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
543		assertEquals(1, s.availablePermits());
124	–	} catch( InterruptedException e){
125	–	fail("unexpected exception");
544		}
545		}
546
547	<	public void testTimedAcquireReleaseInDifferentThreads() {
548	<	final Semaphore s = new Semaphore(1);
549	<	Thread t = new Thread(new Runnable(){
550	<	public void run(){
551	<	try{
552	<	s.release();
553	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
554	<	s.release();
555	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
556	<
557	<	}catch(InterruptedException ie){
558	<	fail("unexpected exception");
559	<	}
560	<	}
561	<	});
562	<	t.start();
563	<	try {
564	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
565	<	s.release();
566	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
567	<	s.release();
568	<	t.join();
569	<	} catch( InterruptedException e){
570	<	fail("unexpected exception");
547	>	/**
548	>	* release in one thread enables acquire in another thread
549	>	*/
550	>	public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
551	>	public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
552	>	public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
553	>	public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
554	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
555	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
556	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
557	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
558	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
559	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
560	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
561	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
562	>	public void testReleaseAcquireDifferentThreads(boolean fair,
563	>	final AcquireMethod acquirer) {
564	>	final Semaphore s = new Semaphore(0, fair);
565	>	final int rounds = 4;
566	>	long startTime = System.nanoTime();
567	>	Thread t = newStartedThread(new CheckedRunnable() {
568	>	public void realRun() throws InterruptedException {
569	>	for (int i = 0; i < rounds; i++) {
570	>	assertFalse(s.hasQueuedThreads());
571	>	if (i % 2 == 0)
572	>	acquirer.acquire(s);
573	>	else
574	>	acquirer.acquire(s, 3);
575	>	}}});
576	>
577	>	for (int i = 0; i < rounds; i++) {
578	>	while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
579	>	Thread.yield();
580	>	assertTrue(t.isAlive());
581	>	if (i % 2 == 0)
582	>	s.release();
583	>	else
584	>	s.release(3);
585		}
586	+	awaitTermination(t);
587	+	assertEquals(0, s.availablePermits());
588	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
589		}
590
591	<	public void testAcquire_InterruptedException(){
592	<	final Semaphore s = new Semaphore(0);
593	<	Thread t = new Thread(new Runnable(){
594	<	public void run(){
595	<	try{
596	<	s.acquire();
597	<	fail("should throw");
598	<	}catch(InterruptedException success){}
599	<	}
600	<	});
601	<	t.start();
602	<	try{
603	<	Thread.sleep(SHORT_DELAY_MS);
604	<	t.interrupt();
605	<	t.join();
606	<	} catch(InterruptedException e){
607	<	fail("unexpected exception");
608	<	}
609	<	}
610	<
611	<	public void testTryAcquire_InterruptedException(){
612	<	final Semaphore s = new Semaphore(0);
613	<	Thread t = new Thread(new Runnable(){
614	<	public void run(){
615	<	try{
616	<	s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
617	<	fail("should throw");
618	<	}catch(InterruptedException success){
619	<	}
620	<	}
621	<	});
622	<	t.start();
623	<	try{
624	<	Thread.sleep(SHORT_DELAY_MS);
625	<	t.interrupt();
626	<	t.join();
627	<	} catch(InterruptedException e){
628	<	fail("unexpected exception");
629	<	}
591	>	/**
592	>	* fair locks are strictly FIFO
593	>	*/
594	>	public void testFairLocksFifo() {
595	>	final PublicSemaphore s = new PublicSemaphore(1, true);
596	>	final CountDownLatch pleaseRelease = new CountDownLatch(1);
597	>	Thread t1 = newStartedThread(new CheckedRunnable() {
598	>	public void realRun() throws InterruptedException {
599	>	// Will block; permits are available, but not three
600	>	s.acquire(3);
601	>	}});
602	>
603	>	waitForQueuedThread(s, t1);
604	>
605	>	Thread t2 = newStartedThread(new CheckedRunnable() {
606	>	public void realRun() throws InterruptedException {
607	>	// Will fail, even though 1 permit is available
608	>	assertFalse(
609	>	s.tryAcquire(randomExpiredTimeout(), randomTimeUnit()));
610	>	assertFalse(
611	>	s.tryAcquire(1, randomExpiredTimeout(), randomTimeUnit()));
612	>
613	>	// untimed tryAcquire will barge and succeed
614	>	assertTrue(s.tryAcquire());
615	>	s.release(2);
616	>	assertTrue(s.tryAcquire(2));
617	>	s.release();
618	>
619	>	pleaseRelease.countDown();
620	>	// Will queue up behind t1, even though 1 permit is available
621	>	s.acquire();
622	>	}});
623	>
624	>	await(pleaseRelease);
625	>	waitForQueuedThread(s, t2);
626	>	s.release(2);
627	>	awaitTermination(t1);
628	>	assertTrue(t2.isAlive());
629	>	s.release();
630	>	awaitTermination(t2);
631	>	}
632	>
633	>	/**
634	>	* toString indicates current number of permits
635	>	*/
636	>	public void testToString()      { testToString(false); }
637	>	public void testToString_fair() { testToString(true); }
638	>	public void testToString(boolean fair) {
639	>	PublicSemaphore s = new PublicSemaphore(0, fair);
640	>	assertTrue(s.toString().contains("Permits = 0"));
641	>	s.release();
642	>	assertTrue(s.toString().contains("Permits = 1"));
643	>	s.release(2);
644	>	assertTrue(s.toString().contains("Permits = 3"));
645	>	s.reducePermits(5);
646	>	assertTrue(s.toString().contains("Permits = -2"));
647		}
648	+
649		}

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