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

Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.5 by dl, Thu Sep 25 11:02:41 2003 UTC vs.
Revision 1.43 by jsr166, Tue Jan 23 20:44:11 2018 UTC

#	Line 1 | Line 1
1		/*
2	<	* Written by members of JCP JSR-166 Expert Group and released to the
3	<	* public domain. Use, modify, and redistribute this code in any way
4	<	* without acknowledgement. Other contributors include Andrew Wright,
5	<	* Jeffrey Hayes, Pat Fischer, Mike Judd.
2	>	* Written by Doug Lea with assistance from members of JCP JSR-166
3	>	* Expert Group and released to the public domain, as explained at
4	>	* http://creativecommons.org/publicdomain/zero/1.0/
5	>	* Other contributors include Andrew Wright, Jeffrey Hayes,
6	>	* Pat Fisher, Mike Judd.
7		*/
8
9	<	import junit.framework.*;
10	<	import java.util.*;
11	<	import java.util.concurrent.*;
12	<	import java.io.*;
9	>	import static java.util.concurrent.TimeUnit.MILLISECONDS;
10	>
11	>	import java.util.Collection;
12	>	import java.util.concurrent.CountDownLatch;
13	>	import java.util.concurrent.Semaphore;
14	>	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		}
23		public static Test suite() {
24	<	return new TestSuite(SemaphoreTest.class);
24	>	return new TestSuite(SemaphoreTest.class);
25	>	}
26	>
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	>	/**
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	>	/**
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		/**
154		* Zero, negative, and positive initial values are allowed in constructor
155		*/
156	<	public void testConstructor() {
157	<	Semaphore s0 = new Semaphore(0);
158	<	assertEquals(0, s0.availablePermits());
159	<	Semaphore s1 = new Semaphore(-1);
160	<	assertEquals(-1, s1.availablePermits());
161	<	Semaphore s2 = new Semaphore(-1);
162	<	assertEquals(-1, s2.availablePermits());
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 sufficent permits, else fails
178	>	* tryAcquire succeeds when sufficient permits, else fails
179		*/
180	<	public void testTryAcquireInSameThread() {
181	<	Semaphore s = new Semaphore(2);
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		/**
194	<	* Acquire and release of semaphore succeed if initially available
194	>	* timed tryAcquire times out
195		*/
196	<	public void testAcquireReleaseInSameThread() {
197	<	Semaphore s = new Semaphore(1);
198	<	try {
199	<	s.acquire();
200	<	s.release();
201	<	s.acquire();
202	<	s.release();
203	<	s.acquire();
204	<	s.release();
205	<	s.acquire();
206	<	s.release();
207	<	s.acquire();
208	<	s.release();
209	<	assertEquals(1, s.availablePermits());
210	<	} catch( InterruptedException e){
211	<	unexpectedException();
196	>	public void testTryAcquire_timeout() {
197	>	final boolean fair = ThreadLocalRandom.current().nextBoolean();
198	>	final Semaphore s = new Semaphore(0, fair);
199	>	final long startTime = System.nanoTime();
200	>	try { assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS)); }
201	>	catch (InterruptedException e) { threadUnexpectedException(e); }
202	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
203	>	}
204	>
205	>	/**
206	>	* timed tryAcquire(N) times out
207	>	*/
208	>	public void testTryAcquireN_timeout() {
209	>	final boolean fair = ThreadLocalRandom.current().nextBoolean();
210	>	final Semaphore s = new Semaphore(2, fair);
211	>	final long startTime = System.nanoTime();
212	>	try { assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS)); }
213	>	catch (InterruptedException e) { threadUnexpectedException(e); }
214	>	assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
215	>	}
216	>
217	>	/**
218	>	* acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
219	>	* are interruptible
220	>	*/
221	>	public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
222	>	public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
223	>	public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
224	>	public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
225	>	public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
226	>	public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
227	>	public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
228	>	public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
229	>	public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
230	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
231	>	final java.util.concurrent.CyclicBarrier pleaseInterrupt
232	>	= new java.util.concurrent.CyclicBarrier(2);
233	>	Thread t = newStartedThread(new CheckedRunnable() {
234	>	public void realRun() {
235	>	// Interrupt before acquire
236	>	Thread.currentThread().interrupt();
237	>	try {
238	>	acquirer.acquire(s);
239	>	shouldThrow();
240	>	} catch (InterruptedException success) {}
241	>	assertFalse(Thread.interrupted());
242	>
243	>	// Interrupt before acquire(N)
244	>	Thread.currentThread().interrupt();
245	>	try {
246	>	acquirer.acquire(s, 3);
247	>	shouldThrow();
248	>	} catch (InterruptedException success) {}
249	>	assertFalse(Thread.interrupted());
250	>
251	>	// Interrupt during acquire
252	>	await(pleaseInterrupt);
253	>	try {
254	>	acquirer.acquire(s);
255	>	shouldThrow();
256	>	} catch (InterruptedException success) {}
257	>	assertFalse(Thread.interrupted());
258	>
259	>	// Interrupt during acquire(N)
260	>	await(pleaseInterrupt);
261	>	try {
262	>	acquirer.acquire(s, 3);
263	>	shouldThrow();
264	>	} catch (InterruptedException success) {}
265	>	assertFalse(Thread.interrupted());
266	>	}});
267	>
268	>	for (int n = 2; n-->0; ) {
269	>	await(pleaseInterrupt);
270	>	assertThreadBlocks(t, acquirer.parkedState());
271	>	t.interrupt();
272		}
273	+
274	+	awaitTermination(t);
275		}
276
277		/**
278	<	* Uninterruptible acquire and release of semaphore succeed if
279	<	* initially available
278	>	* acquireUninterruptibly(), acquireUninterruptibly(N) are
279	>	* uninterruptible
280		*/
281	<	public void testAcquireUninterruptiblyReleaseInSameThread() {
282	<	Semaphore s = new Semaphore(1);
283	<	try {
284	<	s.acquireUninterruptibly();
285	<	s.release();
286	<	s.acquireUninterruptibly();
287	<	s.release();
288	<	s.acquireUninterruptibly();
289	<	s.release();
290	<	s.acquireUninterruptibly();
291	<	s.release();
292	<	s.acquireUninterruptibly();
293	<	s.release();
294	<	assertEquals(1, s.availablePermits());
295	<	} finally {
296	<	}
281	>	public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
282	>	public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
283	>	public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
284	>	public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
285	>	public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
286	>	final PublicSemaphore s = new PublicSemaphore(0, fair);
287	>	final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
288	>
289	>	Thread t1 = newStartedThread(new CheckedRunnable() {
290	>	public void realRun() throws InterruptedException {
291	>	// Interrupt before acquire
292	>	pleaseInterrupt.release();
293	>	Thread.currentThread().interrupt();
294	>	acquirer.acquire(s);
295	>	assertTrue(Thread.interrupted());
296	>	}});
297	>
298	>	Thread t2 = newStartedThread(new CheckedRunnable() {
299	>	public void realRun() throws InterruptedException {
300	>	// Interrupt during acquire
301	>	pleaseInterrupt.release();
302	>	acquirer.acquire(s);
303	>	assertTrue(Thread.interrupted());
304	>	}});
305	>
306	>	await(pleaseInterrupt);
307	>	waitForQueuedThread(s, t1);
308	>	waitForQueuedThread(s, t2);
309	>	t2.interrupt();
310	>
311	>	assertThreadBlocks(t1, Thread.State.WAITING);
312	>	assertThreadBlocks(t2, Thread.State.WAITING);
313	>
314	>	s.release(2);
315	>
316	>	awaitTermination(t1);
317	>	awaitTermination(t2);
318	>	}
319	>
320	>	/**
321	>	* hasQueuedThreads reports whether there are waiting threads
322	>	*/
323	>	public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
324	>	public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
325	>	public void testHasQueuedThreads(boolean fair) {
326	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
327	>	assertFalse(lock.hasQueuedThreads());
328	>	lock.acquireUninterruptibly();
329	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
330	>	waitForQueuedThread(lock, t1);
331	>	assertTrue(lock.hasQueuedThreads());
332	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
333	>	waitForQueuedThread(lock, t2);
334	>	assertTrue(lock.hasQueuedThreads());
335	>	t1.interrupt();
336	>	awaitTermination(t1);
337	>	assertTrue(lock.hasQueuedThreads());
338	>	lock.release();
339	>	awaitTermination(t2);
340	>	assertFalse(lock.hasQueuedThreads());
341	>	}
342	>
343	>	/**
344	>	* getQueueLength reports number of waiting threads
345	>	*/
346	>	public void testGetQueueLength()      { testGetQueueLength(false); }
347	>	public void testGetQueueLength_fair() { testGetQueueLength(true); }
348	>	public void testGetQueueLength(boolean fair) {
349	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
350	>	assertEquals(0, lock.getQueueLength());
351	>	lock.acquireUninterruptibly();
352	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
353	>	waitForQueuedThread(lock, t1);
354	>	assertEquals(1, lock.getQueueLength());
355	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
356	>	waitForQueuedThread(lock, t2);
357	>	assertEquals(2, lock.getQueueLength());
358	>	t1.interrupt();
359	>	awaitTermination(t1);
360	>	assertEquals(1, lock.getQueueLength());
361	>	lock.release();
362	>	awaitTermination(t2);
363	>	assertEquals(0, lock.getQueueLength());
364	>	}
365	>
366	>	/**
367	>	* getQueuedThreads includes waiting threads
368	>	*/
369	>	public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
370	>	public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
371	>	public void testGetQueuedThreads(boolean fair) {
372	>	final PublicSemaphore lock = new PublicSemaphore(1, fair);
373	>	assertTrue(lock.getQueuedThreads().isEmpty());
374	>	lock.acquireUninterruptibly();
375	>	assertTrue(lock.getQueuedThreads().isEmpty());
376	>	Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
377	>	waitForQueuedThread(lock, t1);
378	>	assertTrue(lock.getQueuedThreads().contains(t1));
379	>	Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
380	>	waitForQueuedThread(lock, t2);
381	>	assertTrue(lock.getQueuedThreads().contains(t1));
382	>	assertTrue(lock.getQueuedThreads().contains(t2));
383	>	t1.interrupt();
384	>	awaitTermination(t1);
385	>	assertFalse(lock.getQueuedThreads().contains(t1));
386	>	assertTrue(lock.getQueuedThreads().contains(t2));
387	>	lock.release();
388	>	awaitTermination(t2);
389	>	assertTrue(lock.getQueuedThreads().isEmpty());
390	>	}
391	>
392	>	/**
393	>	* drainPermits reports and removes given number of permits
394	>	*/
395	>	public void testDrainPermits()      { testDrainPermits(false); }
396	>	public void testDrainPermits_fair() { testDrainPermits(true); }
397	>	public void testDrainPermits(boolean fair) {
398	>	Semaphore s = new Semaphore(0, fair);
399	>	assertEquals(0, s.availablePermits());
400	>	assertEquals(0, s.drainPermits());
401	>	s.release(10);
402	>	assertEquals(10, s.availablePermits());
403	>	assertEquals(10, s.drainPermits());
404	>	assertEquals(0, s.availablePermits());
405	>	assertEquals(0, s.drainPermits());
406		}
407
408		/**
409	<	* Timed Acquire and release of semaphore succeed if
91	<	* initially available
409	>	* release(-N) throws IllegalArgumentException
410		*/
411	<	public void testTimedAcquireReleaseInSameThread() {
412	<	Semaphore s = new Semaphore(1);
411	>	public void testReleaseIAE()      { testReleaseIAE(false); }
412	>	public void testReleaseIAE_fair() { testReleaseIAE(true); }
413	>	public void testReleaseIAE(boolean fair) {
414	>	Semaphore s = new Semaphore(10, fair);
415		try {
416	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
417	<	s.release();
418	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
99	<	s.release();
100	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
101	<	s.release();
102	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
103	<	s.release();
104	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
105	<	s.release();
106	<	assertEquals(1, s.availablePermits());
107	<	} catch( InterruptedException e){
108	<	unexpectedException();
109	<	}
416	>	s.release(-1);
417	>	shouldThrow();
418	>	} catch (IllegalArgumentException success) {}
419		}
420
421		/**
422	<	* A release in one thread enables an acquire in another thread
422	>	* reducePermits(-N) throws IllegalArgumentException
423		*/
424	<	public void testAcquireReleaseInDifferentThreads() {
425	<	final Semaphore s = new Semaphore(0);
426	<	Thread t = new Thread(new Runnable() {
427	<	public void run() {
119	<	try {
120	<	s.acquire();
121	<	s.release();
122	<	s.release();
123	<	s.acquire();
124	<	} catch(InterruptedException ie){
125	<	threadUnexpectedException();
126	<	}
127	<	}
128	<	});
424	>	public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
425	>	public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
426	>	public void testReducePermitsIAE(boolean fair) {
427	>	PublicSemaphore s = new PublicSemaphore(10, fair);
428		try {
429	<	t.start();
430	<	Thread.sleep(SHORT_DELAY_MS);
431	<	s.release();
432	<	s.release();
429	>	s.reducePermits(-1);
430	>	shouldThrow();
431	>	} catch (IllegalArgumentException success) {}
432	>	}
433	>
434	>	/**
435	>	* reducePermits reduces number of permits
436	>	*/
437	>	public void testReducePermits()      { testReducePermits(false); }
438	>	public void testReducePermits_fair() { testReducePermits(true); }
439	>	public void testReducePermits(boolean fair) {
440	>	PublicSemaphore s = new PublicSemaphore(10, fair);
441	>	assertEquals(10, s.availablePermits());
442	>	s.reducePermits(0);
443	>	assertEquals(10, s.availablePermits());
444	>	s.reducePermits(1);
445	>	assertEquals(9, s.availablePermits());
446	>	s.reducePermits(10);
447	>	assertEquals(-1, s.availablePermits());
448	>	s.reducePermits(10);
449	>	assertEquals(-11, s.availablePermits());
450	>	s.reducePermits(0);
451	>	assertEquals(-11, s.availablePermits());
452	>	}
453	>
454	>	/**
455	>	* a reserialized semaphore has same number of permits and
456	>	* fairness, but no queued threads
457	>	*/
458	>	public void testSerialization()      { testSerialization(false); }
459	>	public void testSerialization_fair() { testSerialization(true); }
460	>	public void testSerialization(boolean fair) {
461	>	try {
462	>	Semaphore s = new Semaphore(3, fair);
463		s.acquire();
464		s.acquire();
465		s.release();
466	<	t.join();
467	<	} catch( InterruptedException e){
468	<	unexpectedException();
466	>
467	>	Semaphore clone = serialClone(s);
468	>	assertEquals(fair, s.isFair());
469	>	assertEquals(fair, clone.isFair());
470	>	assertEquals(2, s.availablePermits());
471	>	assertEquals(2, clone.availablePermits());
472	>	clone.acquire();
473	>	clone.acquire();
474	>	clone.release();
475	>	assertEquals(2, s.availablePermits());
476	>	assertEquals(1, clone.availablePermits());
477	>	assertFalse(s.hasQueuedThreads());
478	>	assertFalse(clone.hasQueuedThreads());
479	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
480	>
481	>	{
482	>	PublicSemaphore s = new PublicSemaphore(0, fair);
483	>	Thread t = newStartedThread(new InterruptibleLockRunnable(s));
484	>	// waitForQueuedThreads(s); // suffers from "flicker", so ...
485	>	waitForQueuedThread(s, t);  // ... we use this instead
486	>	PublicSemaphore clone = serialClone(s);
487	>	assertEquals(fair, s.isFair());
488	>	assertEquals(fair, clone.isFair());
489	>	assertEquals(0, s.availablePermits());
490	>	assertEquals(0, clone.availablePermits());
491	>	assertTrue(s.hasQueuedThreads());
492	>	assertFalse(clone.hasQueuedThreads());
493	>	s.release();
494	>	awaitTermination(t);
495	>	assertFalse(s.hasQueuedThreads());
496	>	assertFalse(clone.hasQueuedThreads());
497		}
498		}
499
500		/**
501	<	* A release in one thread enables an uninterruptible acquire in another thread
501	>	* tryAcquire(n) succeeds when sufficient permits, else fails
502		*/
503	<	public void testUninterruptibleAcquireReleaseInDifferentThreads() {
504	<	final Semaphore s = new Semaphore(0);
505	<	Thread t = new Thread(new Runnable() {
506	<	public void run() {
507	<	s.acquireUninterruptibly();
508	<	s.release();
509	<	s.release();
510	<	s.acquireUninterruptibly();
511	<	}
512	<	});
513	<	try {
514	<	t.start();
158	<	Thread.sleep(SHORT_DELAY_MS);
159	<	s.release();
160	<	s.release();
161	<	s.acquireUninterruptibly();
162	<	s.acquireUninterruptibly();
163	<	s.release();
164	<	t.join();
165	<	} catch( InterruptedException e){
166	<	unexpectedException();
167	<	}
503	>	public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
504	>	public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
505	>	public void testTryAcquireNInSameThread(boolean fair) {
506	>	Semaphore s = new Semaphore(2, fair);
507	>	assertEquals(2, s.availablePermits());
508	>	assertFalse(s.tryAcquire(3));
509	>	assertEquals(2, s.availablePermits());
510	>	assertTrue(s.tryAcquire(2));
511	>	assertEquals(0, s.availablePermits());
512	>	assertFalse(s.tryAcquire(1));
513	>	assertFalse(s.tryAcquire(2));
514	>	assertEquals(0, s.availablePermits());
515		}
516
170	–
517		/**
518	<	*  A release in one thread enables a timed acquire in another thread
518	>	* acquire succeeds if permits available
519		*/
520	<	public void testTimedAcquireReleaseInDifferentThreads() {
521	<	final Semaphore s = new Semaphore(1);
522	<	Thread t = new Thread(new Runnable() {
523	<	public void run() {
524	<	try {
525	<	s.release();
526	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
527	<	s.release();
528	<	threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
529	<
530	<	} catch(InterruptedException ie){
531	<	threadUnexpectedException();
532	<	}
533	<	}
534	<	});
535	<	try {
536	<	t.start();
537	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
538	<	s.release();
539	<	assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
540	<	s.release();
541	<	s.release();
542	<	t.join();
543	<	} catch( InterruptedException e){
544	<	unexpectedException();
520	>	public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
521	>	public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
522	>	public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
523	>	public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
524	>	public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
525	>	public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
526	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
527	>	public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
528	>	public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
529	>	public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
530	>	public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
531	>	public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
532	>	public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
533	>	public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
534	>	public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
535	>	public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
536	>	public void testReleaseAcquireSameThread(boolean fair,
537	>	final AcquireMethod acquirer) {
538	>	Semaphore s = new Semaphore(1, fair);
539	>	for (int i = 1; i < 6; i++) {
540	>	s.release(i);
541	>	assertEquals(1 + i, s.availablePermits());
542	>	try {
543	>	acquirer.acquire(s, i);
544	>	} catch (InterruptedException e) { threadUnexpectedException(e); }
545	>	assertEquals(1, s.availablePermits());
546		}
547		}
548
549		/**
550	<	* A waiting acquire blocks interruptibly
551	<	*/
552	<	public void testAcquire_InterruptedException() {
553	<	final Semaphore s = new Semaphore(0);
554	<	Thread t = new Thread(new Runnable() {
555	<	public void run() {
556	<	try {
557	<	s.acquire();
558	<	threadShouldThrow();
559	<	} catch(InterruptedException success){}
560	<	}
561	<	});
562	<	t.start();
563	<	try {
564	<	Thread.sleep(SHORT_DELAY_MS);
565	<	t.interrupt();
566	<	t.join();
567	<	} catch(InterruptedException e){
568	<	unexpectedException();
569	<	}
570	<	}
571	<
572	<	/**
573	<	*  A waiting timed acquire blocks interruptibly
574	<	*/
575	<	public void testTryAcquire_InterruptedException() {
576	<	final Semaphore s = new Semaphore(0);
577	<	Thread t = new Thread(new Runnable() {
578	<	public void run() {
579	<	try {
580	<	s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
581	<	threadShouldThrow();
582	<	} catch(InterruptedException success){
583	<	}
584	<	}
585	<	});
586	<	t.start();
240	<	try {
241	<	Thread.sleep(SHORT_DELAY_MS);
242	<	t.interrupt();
243	<	t.join();
244	<	} catch(InterruptedException e){
245	<	unexpectedException();
550	>	* release in one thread enables acquire in another thread
551	>	*/
552	>	public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
553	>	public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
554	>	public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
555	>	public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
556	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
557	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
558	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
559	>	public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
560	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
561	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
562	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
563	>	public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
564	>	public void testReleaseAcquireDifferentThreads(boolean fair,
565	>	final AcquireMethod acquirer) {
566	>	final Semaphore s = new Semaphore(0, fair);
567	>	final int rounds = 4;
568	>	long startTime = System.nanoTime();
569	>	Thread t = newStartedThread(new CheckedRunnable() {
570	>	public void realRun() throws InterruptedException {
571	>	for (int i = 0; i < rounds; i++) {
572	>	assertFalse(s.hasQueuedThreads());
573	>	if (i % 2 == 0)
574	>	acquirer.acquire(s);
575	>	else
576	>	acquirer.acquire(s, 3);
577	>	}}});
578	>
579	>	for (int i = 0; i < rounds; i++) {
580	>	while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
581	>	Thread.yield();
582	>	assertTrue(t.isAlive());
583	>	if (i % 2 == 0)
584	>	s.release();
585	>	else
586	>	s.release(3);
587		}
588	+	awaitTermination(t);
589	+	assertEquals(0, s.availablePermits());
590	+	assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
591		}
592
593		/**
594	<	* a deserialized serialized semaphore has same number of permits
594	>	* fair locks are strictly FIFO
595		*/
596	<	public void testSerialization() {
597	<	Semaphore l = new Semaphore(3);
598	<	try {
599	<	l.acquire();
600	<	l.release();
601	<	ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
602	<	ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
603	<	out.writeObject(l);
604	<	out.close();
605	<
606	<	ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
607	<	ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
608	<	Semaphore r = (Semaphore) in.readObject();
609	<	assertEquals(3, r.availablePermits());
610	<	r.acquire();
611	<	r.release();
612	<	} catch(Exception e){
613	<	unexpectedException();
614	<	}
596	>	public void testFairLocksFifo() {
597	>	final PublicSemaphore s = new PublicSemaphore(1, true);
598	>	final CountDownLatch pleaseRelease = new CountDownLatch(1);
599	>	Thread t1 = newStartedThread(new CheckedRunnable() {
600	>	public void realRun() throws InterruptedException {
601	>	// Will block; permits are available, but not three
602	>	s.acquire(3);
603	>	}});
604	>
605	>	waitForQueuedThread(s, t1);
606	>
607	>	Thread t2 = newStartedThread(new CheckedRunnable() {
608	>	public void realRun() throws InterruptedException {
609	>	// Will fail, even though 1 permit is available
610	>	assertFalse(
611	>	s.tryAcquire(randomExpiredTimeout(), randomTimeUnit()));
612	>	assertFalse(
613	>	s.tryAcquire(1, randomExpiredTimeout(), randomTimeUnit()));
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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