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Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.4 by dl, Sat Sep 20 18:20:08 2003 UTC vs.
Revision 1.22 by jsr166, Tue Dec 1 06:03:49 2009 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/licenses/publicdomain
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 static java.util.concurrent.TimeUnit.MILLISECONDS;
13   import java.io.*;
14  
15   public class SemaphoreTest extends JSR166TestCase {
16      public static void main(String[] args) {
17 <        junit.textui.TestRunner.run (suite());  
17 >        junit.textui.TestRunner.run (suite());
18      }
19      public static Test suite() {
20 <        return new TestSuite(SemaphoreTest.class);
20 >        return new TestSuite(SemaphoreTest.class);
21      }
22  
23      /**
24 <     *
24 >     * Subclass to expose protected methods
25       */
26 <    public void testConstructor1() {
27 <        Semaphore s = new Semaphore(0);
28 <        assertEquals(0, s.availablePermits());
26 >    static class PublicSemaphore extends Semaphore {
27 >        PublicSemaphore(int p, boolean f) { super(p, f); }
28 >        public Collection<Thread> getQueuedThreads() {
29 >            return super.getQueuedThreads();
30 >        }
31 >        public void reducePermits(int p) {
32 >            super.reducePermits(p);
33 >        }
34 >    }
35 >
36 >    /**
37 >     * A runnable calling acquire
38 >     */
39 >    class InterruptibleLockRunnable extends CheckedRunnable {
40 >        final Semaphore lock;
41 >        InterruptibleLockRunnable(Semaphore l) { lock = l; }
42 >        public void realRun() {
43 >            try {
44 >                lock.acquire();
45 >            }
46 >            catch (InterruptedException ignored) {}
47 >        }
48 >    }
49 >
50 >
51 >    /**
52 >     * A runnable calling acquire that expects to be interrupted
53 >     */
54 >    class InterruptedLockRunnable extends CheckedInterruptedRunnable {
55 >        final Semaphore lock;
56 >        InterruptedLockRunnable(Semaphore l) { lock = l; }
57 >        public void realRun() throws InterruptedException {
58 >            lock.acquire();
59 >        }
60      }
61  
62      /**
63 <     *
63 >     * Zero, negative, and positive initial values are allowed in constructor
64 >     */
65 >    public void testConstructor() {
66 >        for (int permits : new int[] { -1, 0, 1 }) {
67 >            for (boolean fair : new boolean[] { false, true }) {
68 >                Semaphore s = new Semaphore(permits, fair);
69 >                assertEquals(permits, s.availablePermits());
70 >                assertEquals(fair, s.isFair());
71 >            }
72 >        }
73 >    }
74 >
75 >    /**
76 >     * Constructor without fairness argument behaves as nonfair
77       */
78      public void testConstructor2() {
79 <        Semaphore s = new Semaphore(-1);
80 <        assertEquals(-1, s.availablePermits());
79 >        for (int permits : new int[] { -1, 0, 1 }) {
80 >            Semaphore s = new Semaphore(permits);
81 >            assertEquals(permits, s.availablePermits());
82 >            assertFalse(s.isFair());
83 >        }
84      }
85  
86      /**
87 <     *
87 >     * tryAcquire succeeds when sufficient permits, else fails
88       */
89      public void testTryAcquireInSameThread() {
90 <        Semaphore s = new Semaphore(2);
90 >        Semaphore s = new Semaphore(2, false);
91          assertEquals(2, s.availablePermits());
92          assertTrue(s.tryAcquire());
93          assertTrue(s.tryAcquire());
# Line 47 | Line 96 | public class SemaphoreTest extends JSR16
96      }
97  
98      /**
99 <     *
99 >     * Acquire and release of semaphore succeed if initially available
100       */
101 <    public void testAcquireReleaseInSameThread() {
102 <        Semaphore s = new Semaphore(1);
103 <        try {
104 <            s.acquire();
105 <            s.release();
106 <            s.acquire();
107 <            s.release();
108 <            s.acquire();
109 <            s.release();
110 <            s.acquire();
111 <            s.release();
112 <            s.acquire();
113 <            s.release();
114 <            assertEquals(1, s.availablePermits());
115 <        } catch( InterruptedException e){
116 <            unexpectedException();
117 <        }
118 <    }
119 <
120 <    /**
121 <     *
122 <     */
123 <    public void testAcquireUninterruptiblyReleaseInSameThread() {
124 <        Semaphore s = new Semaphore(1);
125 <        try {
126 <            s.acquireUninterruptibly();
127 <            s.release();
128 <            s.acquireUninterruptibly();
129 <            s.release();
130 <            s.acquireUninterruptibly();
131 <            s.release();
132 <            s.acquireUninterruptibly();
133 <            s.release();
134 <            s.acquireUninterruptibly();
135 <            s.release();
136 <            assertEquals(1, s.availablePermits());
137 <        } finally {
138 <        }
101 >    public void testAcquireReleaseInSameThread()
102 >        throws InterruptedException {
103 >        Semaphore s = new Semaphore(1, false);
104 >        s.acquire();
105 >        s.release();
106 >        s.acquire();
107 >        s.release();
108 >        s.acquire();
109 >        s.release();
110 >        s.acquire();
111 >        s.release();
112 >        s.acquire();
113 >        s.release();
114 >        assertEquals(1, s.availablePermits());
115 >    }
116 >
117 >    /**
118 >     * Uninterruptible acquire and release of semaphore succeed if
119 >     * initially available
120 >     */
121 >    public void testAcquireUninterruptiblyReleaseInSameThread()
122 >        throws InterruptedException {
123 >        Semaphore s = new Semaphore(1, false);
124 >        s.acquireUninterruptibly();
125 >        s.release();
126 >        s.acquireUninterruptibly();
127 >        s.release();
128 >        s.acquireUninterruptibly();
129 >        s.release();
130 >        s.acquireUninterruptibly();
131 >        s.release();
132 >        s.acquireUninterruptibly();
133 >        s.release();
134 >        assertEquals(1, s.availablePermits());
135 >    }
136 >
137 >    /**
138 >     * Timed Acquire and release of semaphore succeed if
139 >     * initially available
140 >     */
141 >    public void testTimedAcquireReleaseInSameThread()
142 >        throws InterruptedException {
143 >        Semaphore s = new Semaphore(1, false);
144 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
145 >        s.release();
146 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
147 >        s.release();
148 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
149 >        s.release();
150 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
151 >        s.release();
152 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
153 >        s.release();
154 >        assertEquals(1, s.availablePermits());
155 >    }
156 >
157 >    /**
158 >     * A release in one thread enables an acquire in another thread
159 >     */
160 >    public void testAcquireReleaseInDifferentThreads()
161 >        throws InterruptedException {
162 >        final Semaphore s = new Semaphore(0, false);
163 >        Thread t = new Thread(new CheckedRunnable() {
164 >            public void realRun() throws InterruptedException {
165 >                s.acquire();
166 >                s.release();
167 >                s.release();
168 >                s.acquire();
169 >            }});
170 >
171 >        t.start();
172 >        Thread.sleep(SHORT_DELAY_MS);
173 >        s.release();
174 >        s.release();
175 >        s.acquire();
176 >        s.acquire();
177 >        s.release();
178 >        t.join();
179 >    }
180 >
181 >    /**
182 >     * A release in one thread enables an uninterruptible acquire in another thread
183 >     */
184 >    public void testUninterruptibleAcquireReleaseInDifferentThreads()
185 >        throws InterruptedException {
186 >        final Semaphore s = new Semaphore(0, false);
187 >        Thread t = new Thread(new CheckedRunnable() {
188 >            public void realRun() throws InterruptedException {
189 >                s.acquireUninterruptibly();
190 >                s.release();
191 >                s.release();
192 >                s.acquireUninterruptibly();
193 >            }});
194 >
195 >        t.start();
196 >        Thread.sleep(SHORT_DELAY_MS);
197 >        s.release();
198 >        s.release();
199 >        s.acquireUninterruptibly();
200 >        s.acquireUninterruptibly();
201 >        s.release();
202 >        t.join();
203 >    }
204 >
205 >
206 >    /**
207 >     *  A release in one thread enables a timed acquire in another thread
208 >     */
209 >    public void testTimedAcquireReleaseInDifferentThreads()
210 >        throws InterruptedException {
211 >        final Semaphore s = new Semaphore(1, false);
212 >        Thread t = new Thread(new CheckedRunnable() {
213 >            public void realRun() throws InterruptedException {
214 >                s.release();
215 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
216 >                s.release();
217 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
218 >            }});
219 >
220 >        t.start();
221 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
222 >        s.release();
223 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
224 >        s.release();
225 >        s.release();
226 >        t.join();
227 >    }
228 >
229 >    /**
230 >     * A waiting acquire blocks interruptibly
231 >     */
232 >    public void testAcquire_InterruptedException()
233 >        throws InterruptedException {
234 >        final Semaphore s = new Semaphore(0, false);
235 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
236 >            public void realRun() throws InterruptedException {
237 >                s.acquire();
238 >            }});
239 >
240 >        t.start();
241 >        Thread.sleep(SHORT_DELAY_MS);
242 >        t.interrupt();
243 >        t.join();
244 >    }
245 >
246 >    /**
247 >     *  A waiting timed acquire blocks interruptibly
248 >     */
249 >    public void testTryAcquire_InterruptedException()
250 >        throws InterruptedException {
251 >        final Semaphore s = new Semaphore(0, false);
252 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
253 >            public void realRun() throws InterruptedException {
254 >                s.tryAcquire(MEDIUM_DELAY_MS, MILLISECONDS);
255 >            }});
256 >
257 >        t.start();
258 >        Thread.sleep(SHORT_DELAY_MS);
259 >        t.interrupt();
260 >        t.join();
261 >    }
262 >
263 >    /**
264 >     * hasQueuedThreads reports whether there are waiting threads
265 >     */
266 >    public void testHasQueuedThreads() throws InterruptedException {
267 >        final Semaphore lock = new Semaphore(1, false);
268 >        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
269 >        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
270 >        assertFalse(lock.hasQueuedThreads());
271 >        lock.acquireUninterruptibly();
272 >        t1.start();
273 >        Thread.sleep(SHORT_DELAY_MS);
274 >        assertTrue(lock.hasQueuedThreads());
275 >        t2.start();
276 >        Thread.sleep(SHORT_DELAY_MS);
277 >        assertTrue(lock.hasQueuedThreads());
278 >        t1.interrupt();
279 >        Thread.sleep(SHORT_DELAY_MS);
280 >        assertTrue(lock.hasQueuedThreads());
281 >        lock.release();
282 >        Thread.sleep(SHORT_DELAY_MS);
283 >        assertFalse(lock.hasQueuedThreads());
284 >        t1.join();
285 >        t2.join();
286 >    }
287 >
288 >    /**
289 >     * getQueueLength reports number of waiting threads
290 >     */
291 >    public void testGetQueueLength() throws InterruptedException {
292 >        final Semaphore lock = new Semaphore(1, false);
293 >        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
294 >        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
295 >        assertEquals(0, lock.getQueueLength());
296 >        lock.acquireUninterruptibly();
297 >        t1.start();
298 >        Thread.sleep(SHORT_DELAY_MS);
299 >        assertEquals(1, lock.getQueueLength());
300 >        t2.start();
301 >        Thread.sleep(SHORT_DELAY_MS);
302 >        assertEquals(2, lock.getQueueLength());
303 >        t1.interrupt();
304 >        Thread.sleep(SHORT_DELAY_MS);
305 >        assertEquals(1, lock.getQueueLength());
306 >        lock.release();
307 >        Thread.sleep(SHORT_DELAY_MS);
308 >        assertEquals(0, lock.getQueueLength());
309 >        t1.join();
310 >        t2.join();
311 >    }
312 >
313 >    /**
314 >     * getQueuedThreads includes waiting threads
315 >     */
316 >    public void testGetQueuedThreads() throws InterruptedException {
317 >        final PublicSemaphore lock = new PublicSemaphore(1, false);
318 >        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
319 >        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
320 >        assertTrue(lock.getQueuedThreads().isEmpty());
321 >        lock.acquireUninterruptibly();
322 >        assertTrue(lock.getQueuedThreads().isEmpty());
323 >        t1.start();
324 >        Thread.sleep(SHORT_DELAY_MS);
325 >        assertTrue(lock.getQueuedThreads().contains(t1));
326 >        t2.start();
327 >        Thread.sleep(SHORT_DELAY_MS);
328 >        assertTrue(lock.getQueuedThreads().contains(t1));
329 >        assertTrue(lock.getQueuedThreads().contains(t2));
330 >        t1.interrupt();
331 >        Thread.sleep(SHORT_DELAY_MS);
332 >        assertFalse(lock.getQueuedThreads().contains(t1));
333 >        assertTrue(lock.getQueuedThreads().contains(t2));
334 >        lock.release();
335 >        Thread.sleep(SHORT_DELAY_MS);
336 >        assertTrue(lock.getQueuedThreads().isEmpty());
337 >        t1.join();
338 >        t2.join();
339      }
340  
341 +    /**
342 +     * drainPermits reports and removes given number of permits
343 +     */
344 +    public void testDrainPermits() {
345 +        Semaphore s = new Semaphore(0, false);
346 +        assertEquals(0, s.availablePermits());
347 +        assertEquals(0, s.drainPermits());
348 +        s.release(10);
349 +        assertEquals(10, s.availablePermits());
350 +        assertEquals(10, s.drainPermits());
351 +        assertEquals(0, s.availablePermits());
352 +        assertEquals(0, s.drainPermits());
353 +    }
354  
355      /**
356 <     *
357 <     */
358 <    public void testAcquireReleaseInDifferentThreads() {
359 <        final Semaphore s = new Semaphore(1);
360 <        Thread t = new Thread(new Runnable() {
361 <                public void run() {
362 <                    try {
363 <                        s.acquire();
364 <                        s.release();
365 <                        s.release();
366 <                        s.acquire();
367 <                    } catch(InterruptedException ie){
368 <                        threadUnexpectedException();
369 <                    }
370 <                }
371 <            });
372 <        t.start();
373 <        try {
374 <            s.release();
375 <            s.release();
376 <            s.acquire();
377 <            s.acquire();
378 <            t.join();
379 <        } catch( InterruptedException e){
380 <            unexpectedException();
381 <        }
382 <    }
383 <
384 <    /**
385 <     *
386 <     */
387 <    public void testTimedAcquireReleaseInSameThread() {
388 <        Semaphore s = new Semaphore(1);
389 <        try {
390 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
391 <            s.release();
392 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
393 <            s.release();
394 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
395 <            s.release();
396 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
397 <            s.release();
398 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
399 <            s.release();
400 <            assertEquals(1, s.availablePermits());
401 <        } catch( InterruptedException e){
402 <            unexpectedException();
403 <        }
404 <    }
405 <
406 <    /**
407 <     *
408 <     */
409 <    public void testTimedAcquireReleaseInDifferentThreads() {
410 <        final Semaphore s = new Semaphore(1);
411 <        Thread t = new Thread(new Runnable() {
412 <                public void run() {
413 <                    try {
414 <                        s.release();
415 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
416 <                        s.release();
417 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
418 <
419 <                    } catch(InterruptedException ie){
420 <                        threadUnexpectedException();
421 <                    }
422 <                }
423 <            });
424 <        t.start();
425 <        try {
426 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
427 <            s.release();
428 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
429 <            s.release();
430 <            t.join();
431 <        } catch( InterruptedException e){
432 <            unexpectedException();
433 <        }
434 <    }
435 <
436 <    /**
437 <     *
438 <     */
439 <    public void testAcquire_InterruptedException() {
440 <        final Semaphore s = new Semaphore(0);
441 <        Thread t = new Thread(new Runnable() {
442 <                public void run() {
443 <                    try {
444 <                        s.acquire();
445 <                        threadShouldThrow();
446 <                    } catch(InterruptedException success){}
447 <                }
448 <            });
449 <        t.start();
450 <        try {
451 <            Thread.sleep(SHORT_DELAY_MS);
452 <            t.interrupt();
453 <            t.join();
454 <        } catch(InterruptedException e){
455 <            unexpectedException();
456 <        }
457 <    }
458 <    
459 <    /**
460 <     *
461 <     */
462 <    public void testTryAcquire_InterruptedException() {
463 <        final Semaphore s = new Semaphore(0);
464 <        Thread t = new Thread(new Runnable() {
465 <                public void run() {
466 <                    try {
467 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
468 <                        threadShouldThrow();
469 <                    } catch(InterruptedException success){
470 <                    }
471 <                }
472 <            });
473 <        t.start();
474 <        try {
475 <            Thread.sleep(SHORT_DELAY_MS);
476 <            t.interrupt();
477 <            t.join();
478 <        } catch(InterruptedException e){
479 <            unexpectedException();
480 <        }
481 <    }
482 <
483 <    /**
484 <     *
485 <     */
486 <    public void testSerialization() {
487 <        Semaphore l = new Semaphore(3);
488 <        try {
489 <            l.acquire();
490 <            l.release();
491 <            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
492 <            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
493 <            out.writeObject(l);
494 <            out.close();
495 <
496 <            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
497 <            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
498 <            Semaphore r = (Semaphore) in.readObject();
499 <            assertEquals(3, r.availablePermits());
500 <            r.acquire();
501 <            r.release();
502 <        } catch(Exception e){
503 <            unexpectedException();
504 <        }
356 >     * reducePermits reduces number of permits
357 >     */
358 >    public void testReducePermits() {
359 >        PublicSemaphore s = new PublicSemaphore(10, false);
360 >        assertEquals(10, s.availablePermits());
361 >        s.reducePermits(1);
362 >        assertEquals(9, s.availablePermits());
363 >        s.reducePermits(10);
364 >        assertEquals(-1, s.availablePermits());
365 >    }
366 >
367 >    /**
368 >     * a deserialized serialized semaphore has same number of permits
369 >     */
370 >    public void testSerialization() throws Exception {
371 >        Semaphore l = new Semaphore(3, false);
372 >        l.acquire();
373 >        l.release();
374 >        ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
375 >        ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
376 >        out.writeObject(l);
377 >        out.close();
378 >
379 >        ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
380 >        ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
381 >        Semaphore r = (Semaphore) in.readObject();
382 >        assertEquals(3, r.availablePermits());
383 >        assertFalse(r.isFair());
384 >        r.acquire();
385 >        r.release();
386 >    }
387 >
388 >
389 >    /**
390 >     * Zero, negative, and positive initial values are allowed in constructor
391 >     */
392 >    public void testConstructor_fair() {
393 >        Semaphore s0 = new Semaphore(0, true);
394 >        assertEquals(0, s0.availablePermits());
395 >        assertTrue(s0.isFair());
396 >        Semaphore s1 = new Semaphore(-1, true);
397 >        assertEquals(-1, s1.availablePermits());
398 >        Semaphore s2 = new Semaphore(-1, true);
399 >        assertEquals(-1, s2.availablePermits());
400 >    }
401 >
402 >    /**
403 >     * tryAcquire succeeds when sufficient permits, else fails
404 >     */
405 >    public void testTryAcquireInSameThread_fair() {
406 >        Semaphore s = new Semaphore(2, true);
407 >        assertEquals(2, s.availablePermits());
408 >        assertTrue(s.tryAcquire());
409 >        assertTrue(s.tryAcquire());
410 >        assertEquals(0, s.availablePermits());
411 >        assertFalse(s.tryAcquire());
412 >    }
413 >
414 >    /**
415 >     * tryAcquire(n) succeeds when sufficient permits, else fails
416 >     */
417 >    public void testTryAcquireNInSameThread_fair() {
418 >        Semaphore s = new Semaphore(2, true);
419 >        assertEquals(2, s.availablePermits());
420 >        assertTrue(s.tryAcquire(2));
421 >        assertEquals(0, s.availablePermits());
422 >        assertFalse(s.tryAcquire());
423 >    }
424 >
425 >    /**
426 >     * Acquire and release of semaphore succeed if initially available
427 >     */
428 >    public void testAcquireReleaseInSameThread_fair()
429 >        throws InterruptedException {
430 >        Semaphore s = new Semaphore(1, true);
431 >        s.acquire();
432 >        s.release();
433 >        s.acquire();
434 >        s.release();
435 >        s.acquire();
436 >        s.release();
437 >        s.acquire();
438 >        s.release();
439 >        s.acquire();
440 >        s.release();
441 >        assertEquals(1, s.availablePermits());
442 >    }
443 >
444 >    /**
445 >     * Acquire(n) and release(n) of semaphore succeed if initially available
446 >     */
447 >    public void testAcquireReleaseNInSameThread_fair()
448 >        throws InterruptedException {
449 >        Semaphore s = new Semaphore(1, true);
450 >        s.release(1);
451 >        s.acquire(1);
452 >        s.release(2);
453 >        s.acquire(2);
454 >        s.release(3);
455 >        s.acquire(3);
456 >        s.release(4);
457 >        s.acquire(4);
458 >        s.release(5);
459 >        s.acquire(5);
460 >        assertEquals(1, s.availablePermits());
461 >    }
462 >
463 >    /**
464 >     * Acquire(n) and release(n) of semaphore succeed if initially available
465 >     */
466 >    public void testAcquireUninterruptiblyReleaseNInSameThread_fair() {
467 >        Semaphore s = new Semaphore(1, true);
468 >        s.release(1);
469 >        s.acquireUninterruptibly(1);
470 >        s.release(2);
471 >        s.acquireUninterruptibly(2);
472 >        s.release(3);
473 >        s.acquireUninterruptibly(3);
474 >        s.release(4);
475 >        s.acquireUninterruptibly(4);
476 >        s.release(5);
477 >        s.acquireUninterruptibly(5);
478 >        assertEquals(1, s.availablePermits());
479 >    }
480 >
481 >    /**
482 >     * release(n) in one thread enables timed acquire(n) in another thread
483 >     */
484 >    public void testTimedAcquireReleaseNInSameThread_fair()
485 >        throws InterruptedException {
486 >        Semaphore s = new Semaphore(1, true);
487 >        s.release(1);
488 >        assertTrue(s.tryAcquire(1, SHORT_DELAY_MS, MILLISECONDS));
489 >        s.release(2);
490 >        assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
491 >        s.release(3);
492 >        assertTrue(s.tryAcquire(3, SHORT_DELAY_MS, MILLISECONDS));
493 >        s.release(4);
494 >        assertTrue(s.tryAcquire(4, SHORT_DELAY_MS, MILLISECONDS));
495 >        s.release(5);
496 >        assertTrue(s.tryAcquire(5, SHORT_DELAY_MS, MILLISECONDS));
497 >        assertEquals(1, s.availablePermits());
498 >    }
499 >
500 >    /**
501 >     * release in one thread enables timed acquire in another thread
502 >     */
503 >    public void testTimedAcquireReleaseInSameThread_fair()
504 >        throws InterruptedException {
505 >        Semaphore s = new Semaphore(1, true);
506 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
507 >        s.release();
508 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
509 >        s.release();
510 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
511 >        s.release();
512 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
513 >        s.release();
514 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
515 >        s.release();
516 >        assertEquals(1, s.availablePermits());
517 >    }
518 >
519 >    /**
520 >     * A release in one thread enables an acquire in another thread
521 >     */
522 >    public void testAcquireReleaseInDifferentThreads_fair()
523 >        throws InterruptedException {
524 >        final Semaphore s = new Semaphore(0, true);
525 >        Thread t = new Thread(new CheckedRunnable() {
526 >            public void realRun() throws InterruptedException {
527 >                s.acquire();
528 >                s.acquire();
529 >                s.acquire();
530 >                s.acquire();
531 >            }});
532 >
533 >        t.start();
534 >        Thread.sleep(SHORT_DELAY_MS);
535 >        s.release();
536 >        s.release();
537 >        s.release();
538 >        s.release();
539 >        s.release();
540 >        s.release();
541 >        t.join();
542 >        assertEquals(2, s.availablePermits());
543 >    }
544 >
545 >    /**
546 >     * release(n) in one thread enables acquire(n) in another thread
547 >     */
548 >    public void testAcquireReleaseNInDifferentThreads_fair()
549 >        throws InterruptedException {
550 >        final Semaphore s = new Semaphore(0, true);
551 >        Thread t = new Thread(new CheckedRunnable() {
552 >            public void realRun() throws InterruptedException {
553 >                s.acquire();
554 >                s.release(2);
555 >                s.acquire();
556 >            }});
557 >
558 >        t.start();
559 >        Thread.sleep(SHORT_DELAY_MS);
560 >        s.release(2);
561 >        s.acquire(2);
562 >        s.release(1);
563 >        t.join();
564 >    }
565 >
566 >    /**
567 >     * release(n) in one thread enables acquire(n) in another thread
568 >     */
569 >    public void testAcquireReleaseNInDifferentThreads_fair2()
570 >        throws InterruptedException {
571 >        final Semaphore s = new Semaphore(0, true);
572 >        Thread t = new Thread(new CheckedRunnable() {
573 >            public void realRun() throws InterruptedException {
574 >                s.acquire(2);
575 >                s.acquire(2);
576 >                s.release(4);
577 >            }});
578 >
579 >        t.start();
580 >        Thread.sleep(SHORT_DELAY_MS);
581 >        s.release(6);
582 >        s.acquire(2);
583 >        s.acquire(2);
584 >        s.release(2);
585 >        t.join();
586 >    }
587 >
588 >
589 >    /**
590 >     * release in one thread enables timed acquire in another thread
591 >     */
592 >    public void testTimedAcquireReleaseInDifferentThreads_fair()
593 >        throws InterruptedException {
594 >        final Semaphore s = new Semaphore(1, true);
595 >        Thread t = new Thread(new CheckedRunnable() {
596 >            public void realRun() throws InterruptedException {
597 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
598 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
599 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
600 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
601 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
602 >            }});
603 >
604 >        t.start();
605 >        s.release();
606 >        s.release();
607 >        s.release();
608 >        s.release();
609 >        s.release();
610 >        t.join();
611 >    }
612 >
613 >    /**
614 >     * release(n) in one thread enables timed acquire(n) in another thread
615 >     */
616 >    public void testTimedAcquireReleaseNInDifferentThreads_fair()
617 >        throws InterruptedException {
618 >        final Semaphore s = new Semaphore(2, true);
619 >        Thread t = new Thread(new CheckedRunnable() {
620 >            public void realRun() throws InterruptedException {
621 >                assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
622 >                s.release(2);
623 >                assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
624 >                s.release(2);
625 >            }});
626 >
627 >        t.start();
628 >        assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
629 >        s.release(2);
630 >        assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
631 >        s.release(2);
632 >        t.join();
633 >    }
634 >
635 >    /**
636 >     * A waiting acquire blocks interruptibly
637 >     */
638 >    public void testAcquire_InterruptedException_fair()
639 >        throws InterruptedException {
640 >        final Semaphore s = new Semaphore(0, true);
641 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
642 >            public void realRun() throws InterruptedException {
643 >                s.acquire();
644 >            }});
645 >
646 >        t.start();
647 >        Thread.sleep(SHORT_DELAY_MS);
648 >        t.interrupt();
649 >        t.join();
650 >    }
651 >
652 >    /**
653 >     * A waiting acquire(n) blocks interruptibly
654 >     */
655 >    public void testAcquireN_InterruptedException_fair()
656 >        throws InterruptedException {
657 >        final Semaphore s = new Semaphore(2, true);
658 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
659 >            public void realRun() throws InterruptedException {
660 >                s.acquire(3);
661 >            }});
662 >
663 >        t.start();
664 >        Thread.sleep(SHORT_DELAY_MS);
665 >        t.interrupt();
666 >        t.join();
667 >    }
668 >
669 >    /**
670 >     *  A waiting tryAcquire blocks interruptibly
671 >     */
672 >    public void testTryAcquire_InterruptedException_fair()
673 >        throws InterruptedException {
674 >        final Semaphore s = new Semaphore(0, true);
675 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
676 >            public void realRun() throws InterruptedException {
677 >                s.tryAcquire(MEDIUM_DELAY_MS, MILLISECONDS);
678 >            }});
679 >
680 >        t.start();
681 >        Thread.sleep(SHORT_DELAY_MS);
682 >        t.interrupt();
683 >        t.join();
684 >    }
685 >
686 >    /**
687 >     *  A waiting tryAcquire(n) blocks interruptibly
688 >     */
689 >    public void testTryAcquireN_InterruptedException_fair()
690 >        throws InterruptedException {
691 >        final Semaphore s = new Semaphore(1, true);
692 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
693 >            public void realRun() throws InterruptedException {
694 >                s.tryAcquire(4, MEDIUM_DELAY_MS, MILLISECONDS);
695 >            }});
696 >
697 >        t.start();
698 >        Thread.sleep(SHORT_DELAY_MS);
699 >        t.interrupt();
700 >        t.join();
701 >    }
702 >
703 >    /**
704 >     * getQueueLength reports number of waiting threads
705 >     */
706 >    public void testGetQueueLength_fair() throws InterruptedException {
707 >        final Semaphore lock = new Semaphore(1, true);
708 >        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
709 >        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
710 >        assertEquals(0, lock.getQueueLength());
711 >        lock.acquireUninterruptibly();
712 >        t1.start();
713 >        Thread.sleep(SHORT_DELAY_MS);
714 >        assertEquals(1, lock.getQueueLength());
715 >        t2.start();
716 >        Thread.sleep(SHORT_DELAY_MS);
717 >        assertEquals(2, lock.getQueueLength());
718 >        t1.interrupt();
719 >        Thread.sleep(SHORT_DELAY_MS);
720 >        assertEquals(1, lock.getQueueLength());
721 >        lock.release();
722 >        Thread.sleep(SHORT_DELAY_MS);
723 >        assertEquals(0, lock.getQueueLength());
724 >        t1.join();
725 >        t2.join();
726 >    }
727 >
728 >
729 >    /**
730 >     * a deserialized serialized semaphore has same number of permits
731 >     */
732 >    public void testSerialization_fair() throws Exception {
733 >        Semaphore l = new Semaphore(3, true);
734 >
735 >        l.acquire();
736 >        l.release();
737 >        ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
738 >        ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
739 >        out.writeObject(l);
740 >        out.close();
741 >
742 >        ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
743 >        ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
744 >        Semaphore r = (Semaphore) in.readObject();
745 >        assertEquals(3, r.availablePermits());
746 >        assertTrue(r.isFair());
747 >        r.acquire();
748 >        r.release();
749 >    }
750 >
751 >    /**
752 >     * toString indicates current number of permits
753 >     */
754 >    public void testToString() {
755 >        Semaphore s = new Semaphore(0);
756 >        String us = s.toString();
757 >        assertTrue(us.indexOf("Permits = 0") >= 0);
758 >        s.release();
759 >        String s1 = s.toString();
760 >        assertTrue(s1.indexOf("Permits = 1") >= 0);
761 >        s.release();
762 >        String s2 = s.toString();
763 >        assertTrue(s2.indexOf("Permits = 2") >= 0);
764      }
765  
766   }

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