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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 1.37 by jsr166, Sat May 13 23:50:00 2017 UTC

#	Line 1 | Line 1
1		/*
2	<	* Written by members of JCP JSR-166 Expert Group and released to the
3	<	* public domain. Use, modify, and redistribute this code in any way
4	<	* without acknowledgement. Other contributors include Andrew Wright,
5	<	* Jeffrey Hayes, Pat Fischer, Mike Judd.
2	>	* Written by Doug Lea with assistance from members of JCP JSR-166
3	>	* Expert Group and released to the public domain, as explained at
4	>	* http://creativecommons.org/publicdomain/zero/1.0/
5	>	* Other contributors include Andrew Wright, Jeffrey Hayes,
6	>	* Pat Fisher, Mike Judd.
7		*/
8
9	<	import junit.framework.*;
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	>	},
131	>	tryAcquireTimedN {
132	>	void acquire(Semaphore s, int permits) throws InterruptedException {
133	>	assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS));
134	>	}
135	>	};
136	>
137	>	// Intentionally meta-circular
138	>
139	>	/** Acquires 1 permit. */
140	>	void acquire(Semaphore s) throws InterruptedException {
141	>	acquire(s, 1);
142	>	}
143	>	/** Acquires the given number of permits. */
144	>	void acquire(Semaphore s, int permits) throws InterruptedException {
145	>	for (int i = 0; i < permits; i++)
146	>	acquire(s);
147	>	}
148	>	}
149	>
150	>	/**
151	>	* Zero, negative, and positive initial values are allowed in constructor
152	>	*/
153	>	public void testConstructor()      { testConstructor(false); }
154	>	public void testConstructor_fair() { testConstructor(true); }
155	>	public void testConstructor(boolean fair) {
156	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
157	>	Semaphore s = new Semaphore(permits, fair);
158	>	assertEquals(permits, s.availablePermits());
159	>	assertEquals(fair, s.isFair());
160	>	}
161	>	}
162	>
163	>	/**
164	>	* Constructor without fairness argument behaves as nonfair
165	>	*/
166	>	public void testConstructorDefaultsToNonFair() {
167	>	for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
168	>	Semaphore s = new Semaphore(permits);
169	>	assertEquals(permits, s.availablePermits());
170	>	assertFalse(s.isFair());
171	>	}
172		}
173
174	<	public void testTryAcquireInSameThread() {
175	<	Semaphore s = new Semaphore(2);
174	>	/**
175	>	* tryAcquire succeeds when sufficient permits, else fails
176	>	*/
177	>	public void testTryAcquireInSameThread()      { testTryAcquireInSameThread(false); }
178	>	public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); }
179	>	public void testTryAcquireInSameThread(boolean fair) {
180	>	Semaphore s = new Semaphore(2, fair);
181		assertEquals(2, s.availablePermits());
182		assertTrue(s.tryAcquire());
183		assertTrue(s.tryAcquire());
184		assertEquals(0, s.availablePermits());
185		assertFalse(s.tryAcquire());
186	+	assertFalse(s.tryAcquire());
187	+	assertEquals(0, s.availablePermits());
188		}
189
190	<	public void testAcquireReleaseInSameThread(){
191	<	Semaphore s = new Semaphore(1);
192	<	try {
193	<	s.acquire();
194	<	s.release();
195	<	s.acquire();
196	<	s.release();
197	<	s.acquire();
198	<	s.release();
199	<	s.acquire();
200	<	s.release();
201	<	s.acquire();
202	<	s.release();
203	<	assertEquals(1, s.availablePermits());
204	<	} catch( InterruptedException e){
205	<	fail("unexpected exception");
206	<	}
190	>	/**
191	>	* timed tryAcquire times out
192	>	*/
193	>	public void testTryAcquire_timeout()      { testTryAcquire_timeout(false); }
194	>	public void testTryAcquire_timeout_fair() { testTryAcquire_timeout(true); }
195	>	public void testTryAcquire_timeout(boolean fair) {
196	>	Semaphore s = new Semaphore(0, fair);
197	>	long startTime = System.nanoTime();
198	>	try { assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS)); }
199	>	catch (InterruptedException e) { threadUnexpectedException(e); }
200	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
201	>	}
202	>
203	>	/**
204	>	* timed tryAcquire(N) times out
205	>	*/
206	>	public void testTryAcquireN_timeout()      { testTryAcquireN_timeout(false); }
207	>	public void testTryAcquireN_timeout_fair() { testTryAcquireN_timeout(true); }
208	>	public void testTryAcquireN_timeout(boolean fair) {
209	>	Semaphore s = new Semaphore(2, fair);
210	>	long startTime = System.nanoTime();
211	>	try { assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS)); }
212	>	catch (InterruptedException e) { threadUnexpectedException(e); }
213	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
214	>	}
215	>
216	>	/**
217	>	* acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
218	>	* are interruptible
219	>	*/
220	>	public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
221	>	public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
222	>	public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
223	>	public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
224	>	public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
225	>	public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
226	>	public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
227	>	public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
228	>	public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
229	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
230	>	final Semaphore pleaseInterrupt = new Semaphore(0, fair);
231	>	Thread t = newStartedThread(new CheckedRunnable() {
232	>	public void realRun() {
233	>	// Interrupt before acquire
234	>	Thread.currentThread().interrupt();
235	>	try {
236	>	acquirer.acquire(s);
237	>	shouldThrow();
238	>	} catch (InterruptedException success) {}
239	>
240	>	// Interrupt during acquire
241	>	try {
242	>	acquirer.acquire(s);
243	>	shouldThrow();
244	>	} catch (InterruptedException success) {}
245	>
246	>	// Interrupt before acquire(N)
247	>	Thread.currentThread().interrupt();
248	>	try {
249	>	acquirer.acquire(s, 3);
250	>	shouldThrow();
251	>	} catch (InterruptedException success) {}
252	>
253	>	pleaseInterrupt.release();
254	>
255	>	// Interrupt during acquire(N)
256	>	try {
257	>	acquirer.acquire(s, 3);
258	>	shouldThrow();
259	>	} catch (InterruptedException success) {}
260	>	}});
261	>
262	>	waitForQueuedThread(s, t);
263	>	t.interrupt();
264	>	await(pleaseInterrupt);
265	>	waitForQueuedThread(s, t);
266	>	t.interrupt();
267	>	awaitTermination(t);
268	>	}
269	>
270	>	/**
271	>	* acquireUninterruptibly(), acquireUninterruptibly(N) are
272	>	* uninterruptible
273	>	*/
274	>	public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
275	>	public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
276	>	public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
277	>	public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
278	>	public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
279	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
280	>	final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
281	>
282	>	Thread t1 = newStartedThread(new CheckedRunnable() {
283	>	public void realRun() throws InterruptedException {
284	>	// Interrupt before acquire
285	>	pleaseInterrupt.release();
286	>	Thread.currentThread().interrupt();
287	>	acquirer.acquire(s);
288	>	assertTrue(Thread.interrupted());
289	>	}});
290	>
291	>	Thread t2 = newStartedThread(new CheckedRunnable() {
292	>	public void realRun() throws InterruptedException {
293	>	// Interrupt during acquire
294	>	pleaseInterrupt.release();
295	>	acquirer.acquire(s);
296	>	assertTrue(Thread.interrupted());
297	>	}});
298	>
299	>	await(pleaseInterrupt);
300	>	waitForQueuedThread(s, t1);
301	>	waitForQueuedThread(s, t2);
302	>	t2.interrupt();
303	>
304	>	assertThreadBlocks(t1, Thread.State.WAITING);
305	>	assertThreadBlocks(t2, Thread.State.WAITING);
306	>
307	>	s.release(2);
308	>
309	>	awaitTermination(t1);
310	>	awaitTermination(t2);
311	>	}
312	>
313	>	/**
314	>	* hasQueuedThreads reports whether there are waiting threads
315	>	*/
316	>	public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
317	>	public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
318	>	public void testHasQueuedThreads(boolean fair) {
319	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
320	>	assertFalse(lock.hasQueuedThreads());
321	>	lock.acquireUninterruptibly();
322	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
323	>	waitForQueuedThread(lock, t1);
324	>	assertTrue(lock.hasQueuedThreads());
325	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
326	>	waitForQueuedThread(lock, t2);
327	>	assertTrue(lock.hasQueuedThreads());
328	>	t1.interrupt();
329	>	awaitTermination(t1);
330	>	assertTrue(lock.hasQueuedThreads());
331	>	lock.release();
332	>	awaitTermination(t2);
333	>	assertFalse(lock.hasQueuedThreads());
334	>	}
335	>
336	>	/**
337	>	* getQueueLength reports number of waiting threads
338	>	*/
339	>	public void testGetQueueLength()      { testGetQueueLength(false); }
340	>	public void testGetQueueLength_fair() { testGetQueueLength(true); }
341	>	public void testGetQueueLength(boolean fair) {
342	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
343	>	assertEquals(0, lock.getQueueLength());
344	>	lock.acquireUninterruptibly();
345	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
346	>	waitForQueuedThread(lock, t1);
347	>	assertEquals(1, lock.getQueueLength());
348	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
349	>	waitForQueuedThread(lock, t2);
350	>	assertEquals(2, lock.getQueueLength());
351	>	t1.interrupt();
352	>	awaitTermination(t1);
353	>	assertEquals(1, lock.getQueueLength());
354	>	lock.release();
355	>	awaitTermination(t2);
356	>	assertEquals(0, lock.getQueueLength());
357	>	}
358	>
359	>	/**
360	>	* getQueuedThreads includes waiting threads
361	>	*/
362	>	public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
363	>	public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
364	>	public void testGetQueuedThreads(boolean fair) {
365	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
366	>	assertTrue(lock.getQueuedThreads().isEmpty());
367	>	lock.acquireUninterruptibly();
368	>	assertTrue(lock.getQueuedThreads().isEmpty());
369	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
370	>	waitForQueuedThread(lock, t1);
371	>	assertTrue(lock.getQueuedThreads().contains(t1));
372	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
373	>	waitForQueuedThread(lock, t2);
374	>	assertTrue(lock.getQueuedThreads().contains(t1));
375	>	assertTrue(lock.getQueuedThreads().contains(t2));
376	>	t1.interrupt();
377	>	awaitTermination(t1);
378	>	assertFalse(lock.getQueuedThreads().contains(t1));
379	>	assertTrue(lock.getQueuedThreads().contains(t2));
380	>	lock.release();
381	>	awaitTermination(t2);
382	>	assertTrue(lock.getQueuedThreads().isEmpty());
383	>	}
384	>
385	>	/**
386	>	* drainPermits reports and removes given number of permits
387	>	*/
388	>	public void testDrainPermits()      { testDrainPermits(false); }
389	>	public void testDrainPermits_fair() { testDrainPermits(true); }
390	>	public void testDrainPermits(boolean fair) {
391	>	Semaphore s = new Semaphore(0, fair);
392	>	assertEquals(0, s.availablePermits());
393	>	assertEquals(0, s.drainPermits());
394	>	s.release(10);
395	>	assertEquals(10, s.availablePermits());
396	>	assertEquals(10, s.drainPermits());
397	>	assertEquals(0, s.availablePermits());
398	>	assertEquals(0, s.drainPermits());
399		}
400
401	<	public void testAcquireUninterruptiblyReleaseInSameThread(){
402	<	Semaphore s = new Semaphore(1);
401	>	/**
402	>	* release(-N) throws IllegalArgumentException
403	>	*/
404	>	public void testReleaseIAE()      { testReleaseIAE(false); }
405	>	public void testReleaseIAE_fair() { testReleaseIAE(true); }
406	>	public void testReleaseIAE(boolean fair) {
407	>	Semaphore s = new Semaphore(10, fair);
408		try {
409	<	s.acquireUninterruptibly();
410	<	s.release();
411	<	s.acquireUninterruptibly();
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	<	}
409	>	s.release(-1);
410	>	shouldThrow();
411	>	} catch (IllegalArgumentException success) {}
412		}
413
414	+	/**
415	+	* reducePermits(-N) throws IllegalArgumentException
416	+	*/
417	+	public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
418	+	public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
419	+	public void testReducePermitsIAE(boolean fair) {
420	+	PublicSemaphore s = new PublicSemaphore(10, fair);
421	+	try {
422	+	s.reducePermits(-1);
423	+	shouldThrow();
424	+	} catch (IllegalArgumentException success) {}
425	+	}
426	+
427	+	/**
428	+	* reducePermits reduces number of permits
429	+	*/
430	+	public void testReducePermits()      { testReducePermits(false); }
431	+	public void testReducePermits_fair() { testReducePermits(true); }
432	+	public void testReducePermits(boolean fair) {
433	+	PublicSemaphore s = new PublicSemaphore(10, fair);
434	+	assertEquals(10, s.availablePermits());
435	+	s.reducePermits(0);
436	+	assertEquals(10, s.availablePermits());
437	+	s.reducePermits(1);
438	+	assertEquals(9, s.availablePermits());
439	+	s.reducePermits(10);
440	+	assertEquals(-1, s.availablePermits());
441	+	s.reducePermits(10);
442	+	assertEquals(-11, s.availablePermits());
443	+	s.reducePermits(0);
444	+	assertEquals(-11, s.availablePermits());
445	+	}
446
447	<	public void testAcquireReleaseInDifferentThreads() {
448	<	final Semaphore s = new Semaphore(1);
449	<	Thread t = new Thread(new Runnable(){
450	<	public void run(){
451	<	try{
452	<	s.acquire();
453	<	s.release();
92	<	s.release();
93	<	s.acquire();
94	<	}catch(InterruptedException ie){
95	<	fail("unexpected exception");
96	<	}
97	<	}
98	<	});
99	<	t.start();
447	>	/**
448	>	* a reserialized semaphore has same number of permits and
449	>	* fairness, but no queued threads
450	>	*/
451	>	public void testSerialization()      { testSerialization(false); }
452	>	public void testSerialization_fair() { testSerialization(true); }
453	>	public void testSerialization(boolean fair) {
454		try {
455	<	s.release();
102	<	s.release();
455	>	Semaphore s = new Semaphore(3, fair);
456		s.acquire();
457		s.acquire();
458	<	t.join();
459	<	} catch( InterruptedException e){
460	<	fail("unexpected exception");
458	>	s.release();
459	>
460	>	Semaphore clone = serialClone(s);
461	>	assertEquals(fair, s.isFair());
462	>	assertEquals(fair, clone.isFair());
463	>	assertEquals(2, s.availablePermits());
464	>	assertEquals(2, clone.availablePermits());
465	>	clone.acquire();
466	>	clone.acquire();
467	>	clone.release();
468	>	assertEquals(2, s.availablePermits());
469	>	assertEquals(1, clone.availablePermits());
470	>	assertFalse(s.hasQueuedThreads());
471	>	assertFalse(clone.hasQueuedThreads());
472	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
473	>
474	>	{
475	>	PublicSemaphore s = new PublicSemaphore(0, fair);
476	>	Thread t = newStartedThread(new InterruptibleLockRunnable(s));
477	>	// waitForQueuedThreads(s); // suffers from "flicker", so ...
478	>	waitForQueuedThread(s, t);  // ... we use this instead
479	>	PublicSemaphore clone = serialClone(s);
480	>	assertEquals(fair, s.isFair());
481	>	assertEquals(fair, clone.isFair());
482	>	assertEquals(0, s.availablePermits());
483	>	assertEquals(0, clone.availablePermits());
484	>	assertTrue(s.hasQueuedThreads());
485	>	assertFalse(clone.hasQueuedThreads());
486	>	s.release();
487	>	awaitTermination(t);
488	>	assertFalse(s.hasQueuedThreads());
489	>	assertFalse(clone.hasQueuedThreads());
490		}
491		}
492
493	<	public void testTimedAcquireReleaseInSameThread(){
494	<	Semaphore s = new Semaphore(1);
495	<	try {
496	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
497	<	s.release();
498	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
499	<	s.release();
500	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
501	<	s.release();
502	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
503	<	s.release();
504	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
505	<	s.release();
506	<	assertEquals(1, s.availablePermits());
507	<	} catch( InterruptedException e){
126	<	fail("unexpected exception");
127	<	}
493	>	/**
494	>	* tryAcquire(n) succeeds when sufficient permits, else fails
495	>	*/
496	>	public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
497	>	public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
498	>	public void testTryAcquireNInSameThread(boolean fair) {
499	>	Semaphore s = new Semaphore(2, fair);
500	>	assertEquals(2, s.availablePermits());
501	>	assertFalse(s.tryAcquire(3));
502	>	assertEquals(2, s.availablePermits());
503	>	assertTrue(s.tryAcquire(2));
504	>	assertEquals(0, s.availablePermits());
505	>	assertFalse(s.tryAcquire(1));
506	>	assertFalse(s.tryAcquire(2));
507	>	assertEquals(0, s.availablePermits());
508		}
509
510	<	public void testTimedAcquireReleaseInDifferentThreads() {
511	<	final Semaphore s = new Semaphore(1);
512	<	Thread t = new Thread(new Runnable(){
513	<	public void run(){
514	<	try{
515	<	s.release();
516	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
517	<	s.release();
518	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
519	<
520	<	}catch(InterruptedException ie){
521	<	fail("unexpected exception");
522	<	}
523	<	}
524	<	});
525	<	t.start();
526	<	try {
527	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
528	<	s.release();
529	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
530	<	s.release();
531	<	t.join();
532	<	} catch( InterruptedException e){
533	<	fail("unexpected exception");
510	>	/**
511	>	* acquire succeeds if permits available
512	>	*/
513	>	public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
514	>	public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
515	>	public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
516	>	public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
517	>	public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
518	>	public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
519	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
520	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
521	>	public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
522	>	public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
523	>	public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
524	>	public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
525	>	public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
526	>	public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
527	>	public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
528	>	public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
529	>	public void testReleaseAcquireSameThread(boolean fair,
530	>	final AcquireMethod acquirer) {
531	>	Semaphore s = new Semaphore(1, fair);
532	>	for (int i = 1; i < 6; i++) {
533	>	s.release(i);
534	>	assertEquals(1 + i, s.availablePermits());
535	>	try {
536	>	acquirer.acquire(s, i);
537	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
538	>	assertEquals(1, s.availablePermits());
539		}
540		}
541
542	<	public void testAcquire_InterruptedException(){
543	<	final Semaphore s = new Semaphore(0);
544	<	Thread t = new Thread(new Runnable(){
545	<	public void run(){
546	<	try{
547	<	s.acquire();
548	<	fail("should throw");
549	<	}catch(InterruptedException success){}
550	<	}
551	<	});
552	<	t.start();
553	<	try{
554	<	Thread.sleep(SHORT_DELAY_MS);
555	<	t.interrupt();
556	<	t.join();
557	<	} catch(InterruptedException e){
558	<	fail("unexpected exception");
559	<	}
560	<	}
561	<
562	<	public void testTryAcquire_InterruptedException(){
563	<	final Semaphore s = new Semaphore(0);
564	<	Thread t = new Thread(new Runnable(){
565	<	public void run(){
566	<	try{
567	<	s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
568	<	fail("should throw");
569	<	}catch(InterruptedException success){
570	<	}
571	<	}
572	<	});
573	<	t.start();
574	<	try{
575	<	Thread.sleep(SHORT_DELAY_MS);
576	<	t.interrupt();
577	<	t.join();
578	<	} catch(InterruptedException e){
579	<	fail("unexpected exception");
542	>	/**
543	>	* release in one thread enables acquire in another thread
544	>	*/
545	>	public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
546	>	public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
547	>	public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
548	>	public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
549	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
550	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
551	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
552	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
553	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
554	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
555	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
556	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
557	>	public void testReleaseAcquireDifferentThreads(boolean fair,
558	>	final AcquireMethod acquirer) {
559	>	final Semaphore s = new Semaphore(0, fair);
560	>	final int rounds = 4;
561	>	long startTime = System.nanoTime();
562	>	Thread t = newStartedThread(new CheckedRunnable() {
563	>	public void realRun() throws InterruptedException {
564	>	for (int i = 0; i < rounds; i++) {
565	>	assertFalse(s.hasQueuedThreads());
566	>	if (i % 2 == 0)
567	>	acquirer.acquire(s);
568	>	else
569	>	acquirer.acquire(s, 3);
570	>	}}});
571	>
572	>	for (int i = 0; i < rounds; i++) {
573	>	while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
574	>	Thread.yield();
575	>	assertTrue(t.isAlive());
576	>	if (i % 2 == 0)
577	>	s.release();
578	>	else
579	>	s.release(3);
580		}
581	+	awaitTermination(t);
582	+	assertEquals(0, s.availablePermits());
583	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
584		}
585
586	<	public void testSerialization() {
587	<	Semaphore l = new Semaphore(3);
588	<
589	<	try {
590	<	l.acquire();
591	<	l.release();
592	<	ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
593	<	ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
594	<	out.writeObject(l);
595	<	out.close();
596	<
597	<	ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
598	<	ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
599	<	Semaphore r = (Semaphore) in.readObject();
600	<	assertEquals(3, r.availablePermits());
601	<	r.acquire();
602	<	r.release();
603	<	} catch(Exception e){
604	<	e.printStackTrace();
605	<	fail("unexpected exception");
606	<	}
586	>	/**
587	>	* fair locks are strictly FIFO
588	>	*/
589	>	public void testFairLocksFifo() {
590	>	final PublicSemaphore s = new PublicSemaphore(1, true);
591	>	final CountDownLatch pleaseRelease = new CountDownLatch(1);
592	>	Thread t1 = newStartedThread(new CheckedRunnable() {
593	>	public void realRun() throws InterruptedException {
594	>	// Will block; permits are available, but not three
595	>	s.acquire(3);
596	>	}});
597	>
598	>	waitForQueuedThread(s, t1);
599	>
600	>	Thread t2 = newStartedThread(new CheckedRunnable() {
601	>	public void realRun() throws InterruptedException {
602	>	// Will fail, even though 1 permit is available
603	>	assertFalse(s.tryAcquire(0L, MILLISECONDS));
604	>	assertFalse(s.tryAcquire(1, 0L, MILLISECONDS));
605	>
606	>	// untimed tryAcquire will barge and succeed
607	>	assertTrue(s.tryAcquire());
608	>	s.release(2);
609	>	assertTrue(s.tryAcquire(2));
610	>	s.release();
611	>
612	>	pleaseRelease.countDown();
613	>	// Will queue up behind t1, even though 1 permit is available
614	>	s.acquire();
615	>	}});
616	>
617	>	await(pleaseRelease);
618	>	waitForQueuedThread(s, t2);
619	>	s.release(2);
620	>	awaitTermination(t1);
621	>	assertTrue(t2.isAlive());
622	>	s.release();
623	>	awaitTermination(t2);
624	>	}
625	>
626	>	/**
627	>	* toString indicates current number of permits
628	>	*/
629	>	public void testToString()      { testToString(false); }
630	>	public void testToString_fair() { testToString(true); }
631	>	public void testToString(boolean fair) {
632	>	PublicSemaphore s = new PublicSemaphore(0, fair);
633	>	assertTrue(s.toString().contains("Permits = 0"));
634	>	s.release();
635	>	assertTrue(s.toString().contains("Permits = 1"));
636	>	s.release(2);
637	>	assertTrue(s.toString().contains("Permits = 3"));
638	>	s.reducePermits(5);
639	>	assertTrue(s.toString().contains("Permits = -2"));
640		}
641
642		}

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