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

Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.2 by dl, Sun Sep 7 20:39:11 2003 UTC vs.
Revision 1.38 by jsr166, Sun May 14 00:38:16 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 TestCase{
11	>	import java.util.Collection;
12	>	import java.util.concurrent.CountDownLatch;
13	>	import java.util.concurrent.Semaphore;
14
15	+	import junit.framework.AssertionFailedError;
16	+	import junit.framework.Test;
17	+	import junit.framework.TestSuite;
18	+
19	+	public class SemaphoreTest extends JSR166TestCase {
20		public static void main(String[] args) {
21	<	junit.textui.TestRunner.run (suite());
21	>	main(suite(), args);
22		}
18	–
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 AssertionFailedError("timed out");
77	>	Thread.yield();
78	>	}
79	>	assertTrue(s.hasQueuedThreads());
80	>	assertTrue(t.isAlive());
81	>	}
82	>
83	>	/**
84	>	* Spin-waits until s.hasQueuedThreads() becomes true.
85	>	*/
86	>	void waitForQueuedThreads(Semaphore s) {
87	>	long startTime = System.nanoTime();
88	>	while (!s.hasQueuedThreads()) {
89	>	if (millisElapsedSince(startTime) > LONG_DELAY_MS)
90	>	throw new AssertionFailedError("timed out");
91	>	Thread.yield();
92	>	}
93	>	}
94	>
95	>	enum AcquireMethod {
96	>	acquire() {
97	>	void acquire(Semaphore s) throws InterruptedException {
98	>	s.acquire();
99	>	}
100	>	},
101	>	acquireN() {
102	>	void acquire(Semaphore s, int permits) throws InterruptedException {
103	>	s.acquire(permits);
104	>	}
105	>	},
106	>	acquireUninterruptibly() {
107	>	void acquire(Semaphore s) {
108	>	s.acquireUninterruptibly();
109	>	}
110	>	},
111	>	acquireUninterruptiblyN() {
112	>	void acquire(Semaphore s, int permits) {
113	>	s.acquireUninterruptibly(permits);
114	>	}
115	>	},
116	>	tryAcquire() {
117	>	void acquire(Semaphore s) {
118	>	assertTrue(s.tryAcquire());
119	>	}
120	>	},
121	>	tryAcquireN() {
122	>	void acquire(Semaphore s, int permits) {
123	>	assertTrue(s.tryAcquire(permits));
124	>	}
125	>	},
126	>	tryAcquireTimed() {
127	>	void acquire(Semaphore s) throws InterruptedException {
128	>	assertTrue(s.tryAcquire(2 * LONG_DELAY_MS, MILLISECONDS));
129	>	}
130	>	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	>	/**
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	<	public void testTryAcquireInSameThread() {
167	<	Semaphore s = new Semaphore(2);
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()      { testTryAcquire_timeout(false); }
197	>	public void testTryAcquire_timeout_fair() { testTryAcquire_timeout(true); }
198	>	public void testTryAcquire_timeout(boolean fair) {
199	>	Semaphore s = new Semaphore(0, fair);
200	>	long startTime = System.nanoTime();
201	>	try { assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS)); }
202	>	catch (InterruptedException e) { threadUnexpectedException(e); }
203	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
204	>	}
205	>
206	>	/**
207	>	* timed tryAcquire(N) times out
208	>	*/
209	>	public void testTryAcquireN_timeout()      { testTryAcquireN_timeout(false); }
210	>	public void testTryAcquireN_timeout_fair() { testTryAcquireN_timeout(true); }
211	>	public void testTryAcquireN_timeout(boolean fair) {
212	>	Semaphore s = new Semaphore(2, fair);
213	>	long startTime = System.nanoTime();
214	>	try { assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS)); }
215	>	catch (InterruptedException e) { threadUnexpectedException(e); }
216	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
217	>	}
218	>
219	>	/**
220	>	* acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
221	>	* are interruptible
222	>	*/
223	>	public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
224	>	public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
225	>	public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
226	>	public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
227	>	public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
228	>	public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
229	>	public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
230	>	public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
231	>	public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
232	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
233	>	final java.util.concurrent.CyclicBarrier pleaseInterrupt
234	>	= new java.util.concurrent.CyclicBarrier(2);
235	>	Thread t = newStartedThread(new CheckedRunnable() {
236	>	public void realRun() {
237	>	// Interrupt before acquire
238	>	Thread.currentThread().interrupt();
239	>	try {
240	>	acquirer.acquire(s);
241	>	shouldThrow();
242	>	} catch (InterruptedException success) {}
243	>	assertFalse(Thread.interrupted());
244	>
245	>	// Interrupt before acquire(N)
246	>	Thread.currentThread().interrupt();
247	>	try {
248	>	acquirer.acquire(s, 3);
249	>	shouldThrow();
250	>	} catch (InterruptedException success) {}
251	>	assertFalse(Thread.interrupted());
252	>
253	>	// Interrupt during acquire
254	>	await(pleaseInterrupt);
255	>	try {
256	>	acquirer.acquire(s);
257	>	shouldThrow();
258	>	} catch (InterruptedException success) {}
259	>	assertFalse(Thread.interrupted());
260	>
261	>	// Interrupt during acquire(N)
262	>	await(pleaseInterrupt);
263	>	try {
264	>	acquirer.acquire(s, 3);
265	>	shouldThrow();
266	>	} catch (InterruptedException success) {}
267	>	assertFalse(Thread.interrupted());
268	>	}});
269	>
270	>	for (int n = 2; n-->0; ) {
271	>	await(pleaseInterrupt);
272	>	assertThreadBlocks(t, acquirer.parkedState());
273	>	t.interrupt();
274		}
275	+
276	+	awaitTermination(t);
277		}
278
279	<	public void testAcquireUninterruptiblyReleaseInSameThread(){
280	<	Semaphore s = new Semaphore(1);
279	>	/**
280	>	* acquireUninterruptibly(), acquireUninterruptibly(N) are
281	>	* uninterruptible
282	>	*/
283	>	public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
284	>	public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
285	>	public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
286	>	public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
287	>	public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
288	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
289	>	final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
290	>
291	>	Thread t1 = newStartedThread(new CheckedRunnable() {
292	>	public void realRun() throws InterruptedException {
293	>	// Interrupt before acquire
294	>	pleaseInterrupt.release();
295	>	Thread.currentThread().interrupt();
296	>	acquirer.acquire(s);
297	>	assertTrue(Thread.interrupted());
298	>	}});
299	>
300	>	Thread t2 = newStartedThread(new CheckedRunnable() {
301	>	public void realRun() throws InterruptedException {
302	>	// Interrupt during acquire
303	>	pleaseInterrupt.release();
304	>	acquirer.acquire(s);
305	>	assertTrue(Thread.interrupted());
306	>	}});
307	>
308	>	await(pleaseInterrupt);
309	>	waitForQueuedThread(s, t1);
310	>	waitForQueuedThread(s, t2);
311	>	t2.interrupt();
312	>
313	>	assertThreadBlocks(t1, Thread.State.WAITING);
314	>	assertThreadBlocks(t2, Thread.State.WAITING);
315	>
316	>	s.release(2);
317	>
318	>	awaitTermination(t1);
319	>	awaitTermination(t2);
320	>	}
321	>
322	>	/**
323	>	* hasQueuedThreads reports whether there are waiting threads
324	>	*/
325	>	public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
326	>	public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
327	>	public void testHasQueuedThreads(boolean fair) {
328	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
329	>	assertFalse(lock.hasQueuedThreads());
330	>	lock.acquireUninterruptibly();
331	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
332	>	waitForQueuedThread(lock, t1);
333	>	assertTrue(lock.hasQueuedThreads());
334	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
335	>	waitForQueuedThread(lock, t2);
336	>	assertTrue(lock.hasQueuedThreads());
337	>	t1.interrupt();
338	>	awaitTermination(t1);
339	>	assertTrue(lock.hasQueuedThreads());
340	>	lock.release();
341	>	awaitTermination(t2);
342	>	assertFalse(lock.hasQueuedThreads());
343	>	}
344	>
345	>	/**
346	>	* getQueueLength reports number of waiting threads
347	>	*/
348	>	public void testGetQueueLength()      { testGetQueueLength(false); }
349	>	public void testGetQueueLength_fair() { testGetQueueLength(true); }
350	>	public void testGetQueueLength(boolean fair) {
351	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
352	>	assertEquals(0, lock.getQueueLength());
353	>	lock.acquireUninterruptibly();
354	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
355	>	waitForQueuedThread(lock, t1);
356	>	assertEquals(1, lock.getQueueLength());
357	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
358	>	waitForQueuedThread(lock, t2);
359	>	assertEquals(2, lock.getQueueLength());
360	>	t1.interrupt();
361	>	awaitTermination(t1);
362	>	assertEquals(1, lock.getQueueLength());
363	>	lock.release();
364	>	awaitTermination(t2);
365	>	assertEquals(0, lock.getQueueLength());
366	>	}
367	>
368	>	/**
369	>	* getQueuedThreads includes waiting threads
370	>	*/
371	>	public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
372	>	public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
373	>	public void testGetQueuedThreads(boolean fair) {
374	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
375	>	assertTrue(lock.getQueuedThreads().isEmpty());
376	>	lock.acquireUninterruptibly();
377	>	assertTrue(lock.getQueuedThreads().isEmpty());
378	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
379	>	waitForQueuedThread(lock, t1);
380	>	assertTrue(lock.getQueuedThreads().contains(t1));
381	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
382	>	waitForQueuedThread(lock, t2);
383	>	assertTrue(lock.getQueuedThreads().contains(t1));
384	>	assertTrue(lock.getQueuedThreads().contains(t2));
385	>	t1.interrupt();
386	>	awaitTermination(t1);
387	>	assertFalse(lock.getQueuedThreads().contains(t1));
388	>	assertTrue(lock.getQueuedThreads().contains(t2));
389	>	lock.release();
390	>	awaitTermination(t2);
391	>	assertTrue(lock.getQueuedThreads().isEmpty());
392	>	}
393	>
394	>	/**
395	>	* drainPermits reports and removes given number of permits
396	>	*/
397	>	public void testDrainPermits()      { testDrainPermits(false); }
398	>	public void testDrainPermits_fair() { testDrainPermits(true); }
399	>	public void testDrainPermits(boolean fair) {
400	>	Semaphore s = new Semaphore(0, fair);
401	>	assertEquals(0, s.availablePermits());
402	>	assertEquals(0, s.drainPermits());
403	>	s.release(10);
404	>	assertEquals(10, s.availablePermits());
405	>	assertEquals(10, s.drainPermits());
406	>	assertEquals(0, s.availablePermits());
407	>	assertEquals(0, s.drainPermits());
408	>	}
409	>
410	>	/**
411	>	* release(-N) throws IllegalArgumentException
412	>	*/
413	>	public void testReleaseIAE()      { testReleaseIAE(false); }
414	>	public void testReleaseIAE_fair() { testReleaseIAE(true); }
415	>	public void testReleaseIAE(boolean fair) {
416	>	Semaphore s = new Semaphore(10, fair);
417		try {
418	<	s.acquireUninterruptibly();
419	<	s.release();
420	<	s.acquireUninterruptibly();
72	<	s.release();
73	<	s.acquireUninterruptibly();
74	<	s.release();
75	<	s.acquireUninterruptibly();
76	<	s.release();
77	<	s.acquireUninterruptibly();
78	<	s.release();
79	<	assertEquals(1, s.availablePermits());
80	<	} finally {
81	<	}
418	>	s.release(-1);
419	>	shouldThrow();
420	>	} catch (IllegalArgumentException success) {}
421		}
422
423	+	/**
424	+	* reducePermits(-N) throws IllegalArgumentException
425	+	*/
426	+	public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
427	+	public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
428	+	public void testReducePermitsIAE(boolean fair) {
429	+	PublicSemaphore s = new PublicSemaphore(10, fair);
430	+	try {
431	+	s.reducePermits(-1);
432	+	shouldThrow();
433	+	} catch (IllegalArgumentException success) {}
434	+	}
435	+
436	+	/**
437	+	* reducePermits reduces number of permits
438	+	*/
439	+	public void testReducePermits()      { testReducePermits(false); }
440	+	public void testReducePermits_fair() { testReducePermits(true); }
441	+	public void testReducePermits(boolean fair) {
442	+	PublicSemaphore s = new PublicSemaphore(10, fair);
443	+	assertEquals(10, s.availablePermits());
444	+	s.reducePermits(0);
445	+	assertEquals(10, s.availablePermits());
446	+	s.reducePermits(1);
447	+	assertEquals(9, s.availablePermits());
448	+	s.reducePermits(10);
449	+	assertEquals(-1, s.availablePermits());
450	+	s.reducePermits(10);
451	+	assertEquals(-11, s.availablePermits());
452	+	s.reducePermits(0);
453	+	assertEquals(-11, s.availablePermits());
454	+	}
455
456	<	public void testAcquireReleaseInDifferentThreads() {
457	<	final Semaphore s = new Semaphore(1);
458	<	Thread t = new Thread(new Runnable(){
459	<	public void run(){
460	<	try{
461	<	s.acquire();
462	<	s.release();
92	<	s.release();
93	<	s.acquire();
94	<	}catch(InterruptedException ie){
95	<	fail("unexpected exception");
96	<	}
97	<	}
98	<	});
99	<	t.start();
456	>	/**
457	>	* a reserialized semaphore has same number of permits and
458	>	* fairness, but no queued threads
459	>	*/
460	>	public void testSerialization()      { testSerialization(false); }
461	>	public void testSerialization_fair() { testSerialization(true); }
462	>	public void testSerialization(boolean fair) {
463		try {
464	<	s.release();
102	<	s.release();
464	>	Semaphore s = new Semaphore(3, fair);
465		s.acquire();
466		s.acquire();
467	<	t.join();
468	<	} catch( InterruptedException e){
469	<	fail("unexpected exception");
467	>	s.release();
468	>
469	>	Semaphore clone = serialClone(s);
470	>	assertEquals(fair, s.isFair());
471	>	assertEquals(fair, clone.isFair());
472	>	assertEquals(2, s.availablePermits());
473	>	assertEquals(2, clone.availablePermits());
474	>	clone.acquire();
475	>	clone.acquire();
476	>	clone.release();
477	>	assertEquals(2, s.availablePermits());
478	>	assertEquals(1, clone.availablePermits());
479	>	assertFalse(s.hasQueuedThreads());
480	>	assertFalse(clone.hasQueuedThreads());
481	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
482	>
483	>	{
484	>	PublicSemaphore s = new PublicSemaphore(0, fair);
485	>	Thread t = newStartedThread(new InterruptibleLockRunnable(s));
486	>	// waitForQueuedThreads(s); // suffers from "flicker", so ...
487	>	waitForQueuedThread(s, t);  // ... we use this instead
488	>	PublicSemaphore clone = serialClone(s);
489	>	assertEquals(fair, s.isFair());
490	>	assertEquals(fair, clone.isFair());
491	>	assertEquals(0, s.availablePermits());
492	>	assertEquals(0, clone.availablePermits());
493	>	assertTrue(s.hasQueuedThreads());
494	>	assertFalse(clone.hasQueuedThreads());
495	>	s.release();
496	>	awaitTermination(t);
497	>	assertFalse(s.hasQueuedThreads());
498	>	assertFalse(clone.hasQueuedThreads());
499		}
500		}
501
502	<	public void testTimedAcquireReleaseInSameThread(){
503	<	Semaphore s = new Semaphore(1);
504	<	try {
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();
511	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
512	<	s.release();
513	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
514	<	s.release();
515	<	assertEquals(1, s.availablePermits());
516	<	} catch( InterruptedException e){
126	<	fail("unexpected exception");
127	<	}
502	>	/**
503	>	* tryAcquire(n) succeeds when sufficient permits, else fails
504	>	*/
505	>	public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
506	>	public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
507	>	public void testTryAcquireNInSameThread(boolean fair) {
508	>	Semaphore s = new Semaphore(2, fair);
509	>	assertEquals(2, s.availablePermits());
510	>	assertFalse(s.tryAcquire(3));
511	>	assertEquals(2, s.availablePermits());
512	>	assertTrue(s.tryAcquire(2));
513	>	assertEquals(0, s.availablePermits());
514	>	assertFalse(s.tryAcquire(1));
515	>	assertFalse(s.tryAcquire(2));
516	>	assertEquals(0, s.availablePermits());
517		}
518
519	<	public void testTimedAcquireReleaseInDifferentThreads() {
520	<	final Semaphore s = new Semaphore(1);
521	<	Thread t = new Thread(new Runnable(){
522	<	public void run(){
523	<	try{
524	<	s.release();
525	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
526	<	s.release();
527	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
528	<
529	<	}catch(InterruptedException ie){
530	<	fail("unexpected exception");
531	<	}
532	<	}
533	<	});
534	<	t.start();
535	<	try {
536	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
537	<	s.release();
538	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
539	<	s.release();
540	<	t.join();
541	<	} catch( InterruptedException e){
542	<	fail("unexpected exception");
519	>	/**
520	>	* acquire succeeds if permits available
521	>	*/
522	>	public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
523	>	public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
524	>	public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
525	>	public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
526	>	public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
527	>	public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
528	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
529	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
530	>	public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
531	>	public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
532	>	public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
533	>	public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
534	>	public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
535	>	public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
536	>	public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
537	>	public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
538	>	public void testReleaseAcquireSameThread(boolean fair,
539	>	final AcquireMethod acquirer) {
540	>	Semaphore s = new Semaphore(1, fair);
541	>	for (int i = 1; i < 6; i++) {
542	>	s.release(i);
543	>	assertEquals(1 + i, s.availablePermits());
544	>	try {
545	>	acquirer.acquire(s, i);
546	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
547	>	assertEquals(1, s.availablePermits());
548		}
549		}
550
551	<	public void testAcquire_InterruptedException(){
552	<	final Semaphore s = new Semaphore(0);
553	<	Thread t = new Thread(new Runnable(){
554	<	public void run(){
555	<	try{
556	<	s.acquire();
557	<	fail("should throw");
558	<	}catch(InterruptedException success){}
559	<	}
560	<	});
561	<	t.start();
562	<	try{
563	<	Thread.sleep(SHORT_DELAY_MS);
564	<	t.interrupt();
565	<	t.join();
566	<	} catch(InterruptedException e){
567	<	fail("unexpected exception");
568	<	}
569	<	}
570	<
571	<	public void testTryAcquire_InterruptedException(){
572	<	final Semaphore s = new Semaphore(0);
573	<	Thread t = new Thread(new Runnable(){
574	<	public void run(){
575	<	try{
576	<	s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
577	<	fail("should throw");
578	<	}catch(InterruptedException success){
579	<	}
580	<	}
581	<	});
582	<	t.start();
583	<	try{
584	<	Thread.sleep(SHORT_DELAY_MS);
585	<	t.interrupt();
586	<	t.join();
587	<	} catch(InterruptedException e){
588	<	fail("unexpected exception");
551	>	/**
552	>	* release in one thread enables acquire in another thread
553	>	*/
554	>	public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
555	>	public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
556	>	public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
557	>	public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
558	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
559	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
560	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
561	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
562	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
563	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
564	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
565	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
566	>	public void testReleaseAcquireDifferentThreads(boolean fair,
567	>	final AcquireMethod acquirer) {
568	>	final Semaphore s = new Semaphore(0, fair);
569	>	final int rounds = 4;
570	>	long startTime = System.nanoTime();
571	>	Thread t = newStartedThread(new CheckedRunnable() {
572	>	public void realRun() throws InterruptedException {
573	>	for (int i = 0; i < rounds; i++) {
574	>	assertFalse(s.hasQueuedThreads());
575	>	if (i % 2 == 0)
576	>	acquirer.acquire(s);
577	>	else
578	>	acquirer.acquire(s, 3);
579	>	}}});
580	>
581	>	for (int i = 0; i < rounds; i++) {
582	>	while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
583	>	Thread.yield();
584	>	assertTrue(t.isAlive());
585	>	if (i % 2 == 0)
586	>	s.release();
587	>	else
588	>	s.release(3);
589		}
590	+	awaitTermination(t);
591	+	assertEquals(0, s.availablePermits());
592	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
593		}
594
595	<	public void testSerialization() {
596	<	Semaphore l = new Semaphore(3);
597	<
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	<	}
595	>	/**
596	>	* fair locks are strictly FIFO
597	>	*/
598	>	public void testFairLocksFifo() {
599	>	final PublicSemaphore s = new PublicSemaphore(1, true);
600	>	final CountDownLatch pleaseRelease = new CountDownLatch(1);
601	>	Thread t1 = newStartedThread(new CheckedRunnable() {
602	>	public void realRun() throws InterruptedException {
603	>	// Will block; permits are available, but not three
604	>	s.acquire(3);
605	>	}});
606	>
607	>	waitForQueuedThread(s, t1);
608	>
609	>	Thread t2 = newStartedThread(new CheckedRunnable() {
610	>	public void realRun() throws InterruptedException {
611	>	// Will fail, even though 1 permit is available
612	>	assertFalse(s.tryAcquire(0L, MILLISECONDS));
613	>	assertFalse(s.tryAcquire(1, 0L, MILLISECONDS));
614	>
615	>	// untimed tryAcquire will barge and succeed
616	>	assertTrue(s.tryAcquire());
617	>	s.release(2);
618	>	assertTrue(s.tryAcquire(2));
619	>	s.release();
620	>
621	>	pleaseRelease.countDown();
622	>	// Will queue up behind t1, even though 1 permit is available
623	>	s.acquire();
624	>	}});
625	>
626	>	await(pleaseRelease);
627	>	waitForQueuedThread(s, t2);
628	>	s.release(2);
629	>	awaitTermination(t1);
630	>	assertTrue(t2.isAlive());
631	>	s.release();
632	>	awaitTermination(t2);
633	>	}
634	>
635	>	/**
636	>	* toString indicates current number of permits
637	>	*/
638	>	public void testToString()      { testToString(false); }
639	>	public void testToString_fair() { testToString(true); }
640	>	public void testToString(boolean fair) {
641	>	PublicSemaphore s = new PublicSemaphore(0, fair);
642	>	assertTrue(s.toString().contains("Permits = 0"));
643	>	s.release();
644	>	assertTrue(s.toString().contains("Permits = 1"));
645	>	s.release(2);
646	>	assertTrue(s.toString().contains("Permits = 3"));
647	>	s.reducePermits(5);
648	>	assertTrue(s.toString().contains("Permits = -2"));
649		}
650
651		}

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