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Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.1 by dl, Sun Aug 31 19:24:55 2003 UTC vs.
Revision 1.21 by jsr166, Sat Nov 21 17:38:05 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 TestCase{
13 <
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      }
17    
19      public static Test suite() {
20 <        return new TestSuite(SemaphoreTest.class);
20 >        return new TestSuite(SemaphoreTest.class);
21      }
22  
23 <    private static long SHORT_DELAY_MS = 100;
24 <    private static long MEDIUM_DELAY_MS = 1000;
25 <    private static long LONG_DELAY_MS = 10000;
23 >    /**
24 >     * Subclass to expose protected methods
25 >     */
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 <    public void testConstructor1() {
51 <        Semaphore s = new Semaphore(0);
52 <        assertEquals(0, s.availablePermits());
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 >     * 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 +     * 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 43 | Line 95 | public class SemaphoreTest extends TestC
95          assertFalse(s.tryAcquire());
96      }
97  
98 <    public void testAcquireReleaseInSameThread(){
99 <        Semaphore s = new Semaphore(1);
100 <        try {
101 <            s.acquire();
102 <            s.release();
103 <            s.acquire();
104 <            s.release();
105 <            s.acquire();
106 <            s.release();
107 <            s.acquire();
108 <            s.release();
109 <            s.acquire();
110 <            s.release();
111 <            assertEquals(1, s.availablePermits());
112 <        } catch( InterruptedException e){
113 <            fail("unexpected exception");
114 <        }
115 <    }
116 <
117 <    public void testAcquireUninterruptiblyReleaseInSameThread(){
118 <        Semaphore s = new Semaphore(1);
119 <        try {
120 <            s.acquireUninterruptibly();
121 <            s.release();
122 <            s.acquireUninterruptibly();
123 <            s.release();
124 <            s.acquireUninterruptibly();
125 <            s.release();
126 <            s.acquireUninterruptibly();
127 <            s.release();
128 <            s.acquireUninterruptibly();
129 <            s.release();
130 <            assertEquals(1, s.availablePermits());
131 <        } finally {
132 <        }
133 <    }
134 <
135 <
136 <    public void testAcquireReleaseInDifferentThreads() {
137 <        final Semaphore s = new Semaphore(1);
138 <        Thread t = new Thread(new Runnable(){
139 <                public void run(){
140 <                    try{
141 <                        s.acquire();
142 <                        s.release();
143 <                        s.release();
144 <                        s.acquire();
145 <                    }catch(InterruptedException ie){
146 <                        fail("unexpected exception");
147 <                    }
148 <                }
149 <            });
150 <        t.start();
151 <        try {
152 <            s.release();
153 <            s.release();
154 <            s.acquire();
155 <            s.acquire();
156 <            t.join();
157 <        } catch( InterruptedException e){
158 <            fail("unexpected exception");
159 <        }
160 <    }
161 <
162 <    public void testTimedAcquireReleaseInSameThread(){
163 <        Semaphore s = new Semaphore(1);
164 <        try {
165 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
166 <            s.release();
167 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
168 <            s.release();
169 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
170 <            s.release();
171 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
172 <            s.release();
173 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
174 <            s.release();
175 <            assertEquals(1, s.availablePermits());
176 <        } catch( InterruptedException e){
177 <            fail("unexpected exception");
178 <        }
179 <    }
180 <
181 <    public void testTimedAcquireReleaseInDifferentThreads() {
182 <        final Semaphore s = new Semaphore(1);
183 <        Thread t = new Thread(new Runnable(){
184 <                public void run(){
185 <                    try{
186 <                        s.release();
187 <                        assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
188 <                        s.release();
189 <                        assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
190 <
191 <                    }catch(InterruptedException ie){
192 <                        fail("unexpected exception");
193 <                    }
194 <                }
195 <            });
196 <        t.start();
197 <        try {
198 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
199 <            s.release();
200 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
201 <            s.release();
202 <            t.join();
203 <        } catch( InterruptedException e){
204 <            fail("unexpected exception");
205 <        }
206 <    }
207 <
208 <    public void testAcquire_InterruptedException(){
209 <        final Semaphore s = new Semaphore(0);
210 <        Thread t = new Thread(new Runnable(){
211 <                public void run(){
212 <                    try{
213 <                        s.acquire();
214 <                        fail("should throw");
215 <                    }catch(InterruptedException success){}
216 <                }
217 <            });
218 <        t.start();
219 <        try{
220 <            Thread.sleep(SHORT_DELAY_MS);
221 <            t.interrupt();
222 <            t.join();
223 <        } catch(InterruptedException e){
224 <            fail("unexpected exception");
225 <        }
226 <    }
227 <    
228 <    public void testTryAcquire_InterruptedException(){
229 <        final Semaphore s = new Semaphore(0);
230 <        Thread t = new Thread(new Runnable(){
231 <                public void run(){
232 <                    try{
233 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
234 <                        fail("should throw");
235 <                    }catch(InterruptedException success){
236 <                    }
237 <                }
238 <            });
239 <        t.start();
240 <        try{
241 <            Thread.sleep(SHORT_DELAY_MS);
242 <            t.interrupt();
243 <            t.join();
244 <        } catch(InterruptedException e){
245 <            fail("unexpected exception");
246 <        }
98 >    /**
99 >     * Acquire and release of semaphore succeed if initially available
100 >     */
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 +     * 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 +                threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
622 +                s.release(2);
623 +                threadAssertTrue(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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