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Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.5 by dl, Thu Sep 25 11:02:41 2003 UTC vs.
Revision 1.19 by jsr166, Tue Nov 17 02:22:50 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);
21      }
22  
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 +
51 +    /**
52 +     * A runnable calling acquire that expects to be
53 +     * interrupted
54 +     */
55 +    class InterruptedLockRunnable extends CheckedInterruptedRunnable {
56 +        final Semaphore lock;
57 +        InterruptedLockRunnable(Semaphore l) { lock = l; }
58 +        public void realRun() throws InterruptedException {
59 +            lock.acquire();
60 +        }
61 +    }
62 +
63 +    /**
64       * Zero, negative, and positive initial values are allowed in constructor
65       */
66      public void testConstructor() {
67 <        Semaphore s0 = new Semaphore(0);
68 <        assertEquals(0, s0.availablePermits());
69 <        Semaphore s1 = new Semaphore(-1);
70 <        assertEquals(-1, s1.availablePermits());
71 <        Semaphore s2 = new Semaphore(-1);
72 <        assertEquals(-1, s2.availablePermits());
67 >        for (int permits : new int[] { -1, 0, 1 }) {
68 >            for (boolean fair : new boolean[] { false, true }) {
69 >                Semaphore s = new Semaphore(permits, fair);
70 >                assertEquals(permits, s.availablePermits());
71 >                assertEquals(fair, s.isFair());
72 >            }
73 >        }
74      }
75  
76      /**
77 <     * tryAcquire succeeds when sufficent permits, else fails
77 >     * Constructor without fairness argument behaves as nonfair
78 >     */
79 >    public void testConstructor2() {
80 >        for (int permits : new int[] { -1, 0, 1 }) {
81 >            Semaphore s = new Semaphore(permits);
82 >            assertEquals(permits, s.availablePermits());
83 >            assertFalse(s.isFair());
84 >        }
85 >    }
86 >
87 >    /**
88 >     * tryAcquire succeeds when sufficient permits, else fails
89       */
90      public void testTryAcquireInSameThread() {
91 <        Semaphore s = new Semaphore(2);
91 >        Semaphore s = new Semaphore(2, false);
92          assertEquals(2, s.availablePermits());
93          assertTrue(s.tryAcquire());
94          assertTrue(s.tryAcquire());
# Line 45 | Line 99 | public class SemaphoreTest extends JSR16
99      /**
100       * Acquire and release of semaphore succeed if initially available
101       */
102 <    public void testAcquireReleaseInSameThread() {
103 <        Semaphore s = new Semaphore(1);
104 <        try {
105 <            s.acquire();
106 <            s.release();
107 <            s.acquire();
108 <            s.release();
109 <            s.acquire();
110 <            s.release();
111 <            s.acquire();
112 <            s.release();
113 <            s.acquire();
114 <            s.release();
115 <            assertEquals(1, s.availablePermits());
62 <        } catch( InterruptedException e){
63 <            unexpectedException();
64 <        }
102 >    public void testAcquireReleaseInSameThread()
103 >        throws InterruptedException {
104 >        Semaphore s = new Semaphore(1, false);
105 >        s.acquire();
106 >        s.release();
107 >        s.acquire();
108 >        s.release();
109 >        s.acquire();
110 >        s.release();
111 >        s.acquire();
112 >        s.release();
113 >        s.acquire();
114 >        s.release();
115 >        assertEquals(1, s.availablePermits());
116      }
117  
118      /**
119       * Uninterruptible acquire and release of semaphore succeed if
120       * initially available
121       */
122 <    public void testAcquireUninterruptiblyReleaseInSameThread() {
123 <        Semaphore s = new Semaphore(1);
124 <        try {
125 <            s.acquireUninterruptibly();
126 <            s.release();
127 <            s.acquireUninterruptibly();
128 <            s.release();
129 <            s.acquireUninterruptibly();
130 <            s.release();
131 <            s.acquireUninterruptibly();
132 <            s.release();
133 <            s.acquireUninterruptibly();
134 <            s.release();
135 <            assertEquals(1, s.availablePermits());
85 <        } finally {
86 <        }
122 >    public void testAcquireUninterruptiblyReleaseInSameThread()
123 >        throws InterruptedException {
124 >        Semaphore s = new Semaphore(1, false);
125 >        s.acquireUninterruptibly();
126 >        s.release();
127 >        s.acquireUninterruptibly();
128 >        s.release();
129 >        s.acquireUninterruptibly();
130 >        s.release();
131 >        s.acquireUninterruptibly();
132 >        s.release();
133 >        s.acquireUninterruptibly();
134 >        s.release();
135 >        assertEquals(1, s.availablePermits());
136      }
137  
138      /**
139       * Timed Acquire and release of semaphore succeed if
140       * initially available
141       */
142 <    public void testTimedAcquireReleaseInSameThread() {
143 <        Semaphore s = new Semaphore(1);
144 <        try {
145 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
146 <            s.release();
147 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
148 <            s.release();
149 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
150 <            s.release();
151 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
152 <            s.release();
153 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
154 <            s.release();
155 <            assertEquals(1, s.availablePermits());
107 <        } catch( InterruptedException e){
108 <            unexpectedException();
109 <        }
142 >    public void testTimedAcquireReleaseInSameThread()
143 >        throws InterruptedException {
144 >        Semaphore s = new Semaphore(1, false);
145 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
146 >        s.release();
147 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
148 >        s.release();
149 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
150 >        s.release();
151 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
152 >        s.release();
153 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
154 >        s.release();
155 >        assertEquals(1, s.availablePermits());
156      }
157  
158      /**
159       * A release in one thread enables an acquire in another thread
160       */
161 <    public void testAcquireReleaseInDifferentThreads() {
162 <        final Semaphore s = new Semaphore(0);
163 <        Thread t = new Thread(new Runnable() {
164 <                public void run() {
165 <                    try {
166 <                        s.acquire();
167 <                        s.release();
168 <                        s.release();
169 <                        s.acquire();
170 <                    } catch(InterruptedException ie){
171 <                        threadUnexpectedException();
172 <                    }
173 <                }
174 <            });
175 <        try {
176 <            t.start();
177 <            Thread.sleep(SHORT_DELAY_MS);
178 <            s.release();
179 <            s.release();
134 <            s.acquire();
135 <            s.acquire();
136 <            s.release();
137 <            t.join();
138 <        } catch( InterruptedException e){
139 <            unexpectedException();
140 <        }
161 >    public void testAcquireReleaseInDifferentThreads()
162 >        throws InterruptedException {
163 >        final Semaphore s = new Semaphore(0, false);
164 >        Thread t = new Thread(new CheckedRunnable() {
165 >            public void realRun() throws InterruptedException {
166 >                s.acquire();
167 >                s.release();
168 >                s.release();
169 >                s.acquire();
170 >            }});
171 >
172 >        t.start();
173 >        Thread.sleep(SHORT_DELAY_MS);
174 >        s.release();
175 >        s.release();
176 >        s.acquire();
177 >        s.acquire();
178 >        s.release();
179 >        t.join();
180      }
181  
182      /**
183       * A release in one thread enables an uninterruptible acquire in another thread
184       */
185 <    public void testUninterruptibleAcquireReleaseInDifferentThreads() {
186 <        final Semaphore s = new Semaphore(0);
187 <        Thread t = new Thread(new Runnable() {
188 <                public void run() {
189 <                    s.acquireUninterruptibly();
190 <                    s.release();
191 <                    s.release();
192 <                    s.acquireUninterruptibly();
193 <                }
194 <            });
195 <        try {
196 <            t.start();
197 <            Thread.sleep(SHORT_DELAY_MS);
198 <            s.release();
199 <            s.release();
200 <            s.acquireUninterruptibly();
201 <            s.acquireUninterruptibly();
202 <            s.release();
203 <            t.join();
165 <        } catch( InterruptedException e){
166 <            unexpectedException();
167 <        }
185 >    public void testUninterruptibleAcquireReleaseInDifferentThreads()
186 >        throws InterruptedException {
187 >        final Semaphore s = new Semaphore(0, false);
188 >        Thread t = new Thread(new CheckedRunnable() {
189 >            public void realRun() throws InterruptedException {
190 >                s.acquireUninterruptibly();
191 >                s.release();
192 >                s.release();
193 >                s.acquireUninterruptibly();
194 >            }});
195 >
196 >        t.start();
197 >        Thread.sleep(SHORT_DELAY_MS);
198 >        s.release();
199 >        s.release();
200 >        s.acquireUninterruptibly();
201 >        s.acquireUninterruptibly();
202 >        s.release();
203 >        t.join();
204      }
205  
206  
207      /**
208       *  A release in one thread enables a timed acquire in another thread
209       */
210 <    public void testTimedAcquireReleaseInDifferentThreads() {
211 <        final Semaphore s = new Semaphore(1);
212 <        Thread t = new Thread(new Runnable() {
213 <                public void run() {
214 <                    try {
215 <                        s.release();
216 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
217 <                        s.release();
218 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
219 <
220 <                    } catch(InterruptedException ie){
221 <                        threadUnexpectedException();
222 <                    }
223 <                }
224 <            });
225 <        try {
226 <            t.start();
227 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
192 <            s.release();
193 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
194 <            s.release();
195 <            s.release();
196 <            t.join();
197 <        } catch( InterruptedException e){
198 <            unexpectedException();
199 <        }
210 >    public void testTimedAcquireReleaseInDifferentThreads()
211 >        throws InterruptedException {
212 >        final Semaphore s = new Semaphore(1, false);
213 >        Thread t = new Thread(new CheckedRunnable() {
214 >            public void realRun() throws InterruptedException {
215 >                s.release();
216 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
217 >                s.release();
218 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
219 >            }});
220 >
221 >        t.start();
222 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
223 >        s.release();
224 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
225 >        s.release();
226 >        s.release();
227 >        t.join();
228      }
229  
230      /**
231       * A waiting acquire blocks interruptibly
232       */
233 <    public void testAcquire_InterruptedException() {
234 <        final Semaphore s = new Semaphore(0);
235 <        Thread t = new Thread(new Runnable() {
236 <                public void run() {
237 <                    try {
238 <                        s.acquire();
239 <                        threadShouldThrow();
240 <                    } catch(InterruptedException success){}
213 <                }
214 <            });
233 >    public void testAcquire_InterruptedException()
234 >        throws InterruptedException {
235 >        final Semaphore s = new Semaphore(0, false);
236 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
237 >            public void realRun() throws InterruptedException {
238 >                s.acquire();
239 >            }});
240 >
241          t.start();
242 <        try {
243 <            Thread.sleep(SHORT_DELAY_MS);
244 <            t.interrupt();
219 <            t.join();
220 <        } catch(InterruptedException e){
221 <            unexpectedException();
222 <        }
242 >        Thread.sleep(SHORT_DELAY_MS);
243 >        t.interrupt();
244 >        t.join();
245      }
246 <    
246 >
247      /**
248       *  A waiting timed acquire blocks interruptibly
249       */
250 <    public void testTryAcquire_InterruptedException() {
251 <        final Semaphore s = new Semaphore(0);
252 <        Thread t = new Thread(new Runnable() {
253 <                public void run() {
254 <                    try {
255 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
256 <                        threadShouldThrow();
257 <                    } catch(InterruptedException success){
236 <                    }
237 <                }
238 <            });
250 >    public void testTryAcquire_InterruptedException()
251 >        throws InterruptedException {
252 >        final Semaphore s = new Semaphore(0, false);
253 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
254 >            public void realRun() throws InterruptedException {
255 >                s.tryAcquire(MEDIUM_DELAY_MS, MILLISECONDS);
256 >            }});
257 >
258          t.start();
259 <        try {
260 <            Thread.sleep(SHORT_DELAY_MS);
261 <            t.interrupt();
262 <            t.join();
263 <        } catch(InterruptedException e){
264 <            unexpectedException();
265 <        }
259 >        Thread.sleep(SHORT_DELAY_MS);
260 >        t.interrupt();
261 >        t.join();
262 >    }
263 >
264 >    /**
265 >     * hasQueuedThreads reports whether there are waiting threads
266 >     */
267 >    public void testHasQueuedThreads() throws InterruptedException {
268 >        final Semaphore lock = new Semaphore(1, false);
269 >        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
270 >        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
271 >        assertFalse(lock.hasQueuedThreads());
272 >        lock.acquireUninterruptibly();
273 >        t1.start();
274 >        Thread.sleep(SHORT_DELAY_MS);
275 >        assertTrue(lock.hasQueuedThreads());
276 >        t2.start();
277 >        Thread.sleep(SHORT_DELAY_MS);
278 >        assertTrue(lock.hasQueuedThreads());
279 >        t1.interrupt();
280 >        Thread.sleep(SHORT_DELAY_MS);
281 >        assertTrue(lock.hasQueuedThreads());
282 >        lock.release();
283 >        Thread.sleep(SHORT_DELAY_MS);
284 >        assertFalse(lock.hasQueuedThreads());
285 >        t1.join();
286 >        t2.join();
287 >    }
288 >
289 >    /**
290 >     * getQueueLength reports number of waiting threads
291 >     */
292 >    public void testGetQueueLength() throws InterruptedException {
293 >        final Semaphore lock = new Semaphore(1, false);
294 >        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
295 >        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
296 >        assertEquals(0, lock.getQueueLength());
297 >        lock.acquireUninterruptibly();
298 >        t1.start();
299 >        Thread.sleep(SHORT_DELAY_MS);
300 >        assertEquals(1, lock.getQueueLength());
301 >        t2.start();
302 >        Thread.sleep(SHORT_DELAY_MS);
303 >        assertEquals(2, lock.getQueueLength());
304 >        t1.interrupt();
305 >        Thread.sleep(SHORT_DELAY_MS);
306 >        assertEquals(1, lock.getQueueLength());
307 >        lock.release();
308 >        Thread.sleep(SHORT_DELAY_MS);
309 >        assertEquals(0, lock.getQueueLength());
310 >        t1.join();
311 >        t2.join();
312 >    }
313 >
314 >    /**
315 >     * getQueuedThreads includes waiting threads
316 >     */
317 >    public void testGetQueuedThreads() throws InterruptedException {
318 >        final PublicSemaphore lock = new PublicSemaphore(1, false);
319 >        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
320 >        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
321 >        assertTrue(lock.getQueuedThreads().isEmpty());
322 >        lock.acquireUninterruptibly();
323 >        assertTrue(lock.getQueuedThreads().isEmpty());
324 >        t1.start();
325 >        Thread.sleep(SHORT_DELAY_MS);
326 >        assertTrue(lock.getQueuedThreads().contains(t1));
327 >        t2.start();
328 >        Thread.sleep(SHORT_DELAY_MS);
329 >        assertTrue(lock.getQueuedThreads().contains(t1));
330 >        assertTrue(lock.getQueuedThreads().contains(t2));
331 >        t1.interrupt();
332 >        Thread.sleep(SHORT_DELAY_MS);
333 >        assertFalse(lock.getQueuedThreads().contains(t1));
334 >        assertTrue(lock.getQueuedThreads().contains(t2));
335 >        lock.release();
336 >        Thread.sleep(SHORT_DELAY_MS);
337 >        assertTrue(lock.getQueuedThreads().isEmpty());
338 >        t1.join();
339 >        t2.join();
340 >    }
341 >
342 >    /**
343 >     * drainPermits reports and removes given number of permits
344 >     */
345 >    public void testDrainPermits() {
346 >        Semaphore s = new Semaphore(0, false);
347 >        assertEquals(0, s.availablePermits());
348 >        assertEquals(0, s.drainPermits());
349 >        s.release(10);
350 >        assertEquals(10, s.availablePermits());
351 >        assertEquals(10, s.drainPermits());
352 >        assertEquals(0, s.availablePermits());
353 >        assertEquals(0, s.drainPermits());
354 >    }
355 >
356 >    /**
357 >     * reducePermits reduces number of permits
358 >     */
359 >    public void testReducePermits() {
360 >        PublicSemaphore s = new PublicSemaphore(10, false);
361 >        assertEquals(10, s.availablePermits());
362 >        s.reducePermits(1);
363 >        assertEquals(9, s.availablePermits());
364 >        s.reducePermits(10);
365 >        assertEquals(-1, s.availablePermits());
366      }
367  
368      /**
369       * a deserialized serialized semaphore has same number of permits
370       */
371 <    public void testSerialization() {
372 <        Semaphore l = new Semaphore(3);
373 <        try {
374 <            l.acquire();
375 <            l.release();
376 <            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
377 <            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
378 <            out.writeObject(l);
379 <            out.close();
380 <
381 <            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
382 <            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
383 <            Semaphore r = (Semaphore) in.readObject();
384 <            assertEquals(3, r.availablePermits());
385 <            r.acquire();
386 <            r.release();
387 <        } catch(Exception e){
388 <            unexpectedException();
389 <        }
371 >    public void testSerialization() throws Exception {
372 >        Semaphore l = new Semaphore(3, false);
373 >        l.acquire();
374 >        l.release();
375 >        ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
376 >        ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
377 >        out.writeObject(l);
378 >        out.close();
379 >
380 >        ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
381 >        ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
382 >        Semaphore r = (Semaphore) in.readObject();
383 >        assertEquals(3, r.availablePermits());
384 >        assertFalse(r.isFair());
385 >        r.acquire();
386 >        r.release();
387 >    }
388 >
389 >
390 >    /**
391 >     * Zero, negative, and positive initial values are allowed in constructor
392 >     */
393 >    public void testConstructor_fair() {
394 >        Semaphore s0 = new Semaphore(0, true);
395 >        assertEquals(0, s0.availablePermits());
396 >        assertTrue(s0.isFair());
397 >        Semaphore s1 = new Semaphore(-1, true);
398 >        assertEquals(-1, s1.availablePermits());
399 >        Semaphore s2 = new Semaphore(-1, true);
400 >        assertEquals(-1, s2.availablePermits());
401 >    }
402 >
403 >    /**
404 >     * tryAcquire succeeds when sufficient permits, else fails
405 >     */
406 >    public void testTryAcquireInSameThread_fair() {
407 >        Semaphore s = new Semaphore(2, true);
408 >        assertEquals(2, s.availablePermits());
409 >        assertTrue(s.tryAcquire());
410 >        assertTrue(s.tryAcquire());
411 >        assertEquals(0, s.availablePermits());
412 >        assertFalse(s.tryAcquire());
413 >    }
414 >
415 >    /**
416 >     * tryAcquire(n) succeeds when sufficient permits, else fails
417 >     */
418 >    public void testTryAcquireNInSameThread_fair() {
419 >        Semaphore s = new Semaphore(2, true);
420 >        assertEquals(2, s.availablePermits());
421 >        assertTrue(s.tryAcquire(2));
422 >        assertEquals(0, s.availablePermits());
423 >        assertFalse(s.tryAcquire());
424 >    }
425 >
426 >    /**
427 >     * Acquire and release of semaphore succeed if initially available
428 >     */
429 >    public void testAcquireReleaseInSameThread_fair()
430 >        throws InterruptedException {
431 >        Semaphore s = new Semaphore(1, true);
432 >        s.acquire();
433 >        s.release();
434 >        s.acquire();
435 >        s.release();
436 >        s.acquire();
437 >        s.release();
438 >        s.acquire();
439 >        s.release();
440 >        s.acquire();
441 >        s.release();
442 >        assertEquals(1, s.availablePermits());
443 >    }
444 >
445 >    /**
446 >     * Acquire(n) and release(n) of semaphore succeed if initially available
447 >     */
448 >    public void testAcquireReleaseNInSameThread_fair()
449 >        throws InterruptedException {
450 >        Semaphore s = new Semaphore(1, true);
451 >        s.release(1);
452 >        s.acquire(1);
453 >        s.release(2);
454 >        s.acquire(2);
455 >        s.release(3);
456 >        s.acquire(3);
457 >        s.release(4);
458 >        s.acquire(4);
459 >        s.release(5);
460 >        s.acquire(5);
461 >        assertEquals(1, s.availablePermits());
462 >    }
463 >
464 >    /**
465 >     * Acquire(n) and release(n) of semaphore succeed if initially available
466 >     */
467 >    public void testAcquireUninterruptiblyReleaseNInSameThread_fair() {
468 >        Semaphore s = new Semaphore(1, true);
469 >        s.release(1);
470 >        s.acquireUninterruptibly(1);
471 >        s.release(2);
472 >        s.acquireUninterruptibly(2);
473 >        s.release(3);
474 >        s.acquireUninterruptibly(3);
475 >        s.release(4);
476 >        s.acquireUninterruptibly(4);
477 >        s.release(5);
478 >        s.acquireUninterruptibly(5);
479 >        assertEquals(1, s.availablePermits());
480 >    }
481 >
482 >    /**
483 >     * release(n) in one thread enables timed acquire(n) in another thread
484 >     */
485 >    public void testTimedAcquireReleaseNInSameThread_fair()
486 >        throws InterruptedException {
487 >        Semaphore s = new Semaphore(1, true);
488 >        s.release(1);
489 >        assertTrue(s.tryAcquire(1, SHORT_DELAY_MS, MILLISECONDS));
490 >        s.release(2);
491 >        assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
492 >        s.release(3);
493 >        assertTrue(s.tryAcquire(3, SHORT_DELAY_MS, MILLISECONDS));
494 >        s.release(4);
495 >        assertTrue(s.tryAcquire(4, SHORT_DELAY_MS, MILLISECONDS));
496 >        s.release(5);
497 >        assertTrue(s.tryAcquire(5, SHORT_DELAY_MS, MILLISECONDS));
498 >        assertEquals(1, s.availablePermits());
499 >    }
500 >
501 >    /**
502 >     * release in one thread enables timed acquire in another thread
503 >     */
504 >    public void testTimedAcquireReleaseInSameThread_fair()
505 >        throws InterruptedException {
506 >        Semaphore s = new Semaphore(1, true);
507 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
508 >        s.release();
509 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
510 >        s.release();
511 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
512 >        s.release();
513 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
514 >        s.release();
515 >        assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
516 >        s.release();
517 >        assertEquals(1, s.availablePermits());
518 >    }
519 >
520 >    /**
521 >     * A release in one thread enables an acquire in another thread
522 >     */
523 >    public void testAcquireReleaseInDifferentThreads_fair()
524 >        throws InterruptedException {
525 >        final Semaphore s = new Semaphore(0, true);
526 >        Thread t = new Thread(new CheckedRunnable() {
527 >            public void realRun() throws InterruptedException {
528 >                s.acquire();
529 >                s.acquire();
530 >                s.acquire();
531 >                s.acquire();
532 >            }});
533 >
534 >        t.start();
535 >        Thread.sleep(SHORT_DELAY_MS);
536 >        s.release();
537 >        s.release();
538 >        s.release();
539 >        s.release();
540 >        s.release();
541 >        s.release();
542 >        t.join();
543 >        assertEquals(2, s.availablePermits());
544 >    }
545 >
546 >    /**
547 >     * release(n) in one thread enables acquire(n) in another thread
548 >     */
549 >    public void testAcquireReleaseNInDifferentThreads_fair()
550 >        throws InterruptedException {
551 >        final Semaphore s = new Semaphore(0, true);
552 >        Thread t = new Thread(new CheckedRunnable() {
553 >            public void realRun() throws InterruptedException {
554 >                s.acquire();
555 >                s.release(2);
556 >                s.acquire();
557 >            }});
558 >
559 >        t.start();
560 >        Thread.sleep(SHORT_DELAY_MS);
561 >        s.release(2);
562 >        s.acquire(2);
563 >        s.release(1);
564 >        t.join();
565 >    }
566 >
567 >    /**
568 >     * release(n) in one thread enables acquire(n) in another thread
569 >     */
570 >    public void testAcquireReleaseNInDifferentThreads_fair2()
571 >        throws InterruptedException {
572 >        final Semaphore s = new Semaphore(0, true);
573 >        Thread t = new Thread(new CheckedRunnable() {
574 >            public void realRun() throws InterruptedException {
575 >                s.acquire(2);
576 >                s.acquire(2);
577 >                s.release(4);
578 >            }});
579 >
580 >        t.start();
581 >        Thread.sleep(SHORT_DELAY_MS);
582 >        s.release(6);
583 >        s.acquire(2);
584 >        s.acquire(2);
585 >        s.release(2);
586 >        t.join();
587 >    }
588 >
589 >
590 >    /**
591 >     * release in one thread enables timed acquire in another thread
592 >     */
593 >    public void testTimedAcquireReleaseInDifferentThreads_fair()
594 >        throws InterruptedException {
595 >        final Semaphore s = new Semaphore(1, true);
596 >        Thread t = new Thread(new CheckedRunnable() {
597 >            public void realRun() throws InterruptedException {
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 >                threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
603 >            }});
604 >
605 >        t.start();
606 >        s.release();
607 >        s.release();
608 >        s.release();
609 >        s.release();
610 >        s.release();
611 >        t.join();
612 >    }
613 >
614 >    /**
615 >     * release(n) in one thread enables timed acquire(n) in another thread
616 >     */
617 >    public void testTimedAcquireReleaseNInDifferentThreads_fair()
618 >        throws InterruptedException {
619 >        final Semaphore s = new Semaphore(2, true);
620 >        Thread t = new Thread(new CheckedRunnable() {
621 >            public void realRun() throws InterruptedException {
622 >                threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
623 >                s.release(2);
624 >                threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
625 >                s.release(2);
626 >            }});
627 >
628 >        t.start();
629 >        assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
630 >        s.release(2);
631 >        assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, MILLISECONDS));
632 >        s.release(2);
633 >        t.join();
634 >    }
635 >
636 >    /**
637 >     * A waiting acquire blocks interruptibly
638 >     */
639 >    public void testAcquire_InterruptedException_fair()
640 >        throws InterruptedException {
641 >        final Semaphore s = new Semaphore(0, true);
642 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
643 >            public void realRun() throws InterruptedException {
644 >                s.acquire();
645 >            }});
646 >
647 >        t.start();
648 >        Thread.sleep(SHORT_DELAY_MS);
649 >        t.interrupt();
650 >        t.join();
651 >    }
652 >
653 >    /**
654 >     * A waiting acquire(n) blocks interruptibly
655 >     */
656 >    public void testAcquireN_InterruptedException_fair()
657 >        throws InterruptedException {
658 >        final Semaphore s = new Semaphore(2, true);
659 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
660 >            public void realRun() throws InterruptedException {
661 >                s.acquire(3);
662 >            }});
663 >
664 >        t.start();
665 >        Thread.sleep(SHORT_DELAY_MS);
666 >        t.interrupt();
667 >        t.join();
668 >    }
669 >
670 >    /**
671 >     *  A waiting tryAcquire blocks interruptibly
672 >     */
673 >    public void testTryAcquire_InterruptedException_fair()
674 >        throws InterruptedException {
675 >        final Semaphore s = new Semaphore(0, true);
676 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
677 >            public void realRun() throws InterruptedException {
678 >                s.tryAcquire(MEDIUM_DELAY_MS, MILLISECONDS);
679 >            }});
680 >
681 >        t.start();
682 >        Thread.sleep(SHORT_DELAY_MS);
683 >        t.interrupt();
684 >        t.join();
685 >    }
686 >
687 >    /**
688 >     *  A waiting tryAcquire(n) blocks interruptibly
689 >     */
690 >    public void testTryAcquireN_InterruptedException_fair()
691 >        throws InterruptedException {
692 >        final Semaphore s = new Semaphore(1, true);
693 >        Thread t = new Thread(new CheckedInterruptedRunnable() {
694 >            public void realRun() throws InterruptedException {
695 >                s.tryAcquire(4, MEDIUM_DELAY_MS, MILLISECONDS);
696 >            }});
697 >
698 >        t.start();
699 >        Thread.sleep(SHORT_DELAY_MS);
700 >        t.interrupt();
701 >        t.join();
702 >    }
703 >
704 >    /**
705 >     * getQueueLength reports number of waiting threads
706 >     */
707 >    public void testGetQueueLength_fair() throws InterruptedException {
708 >        final Semaphore lock = new Semaphore(1, true);
709 >        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
710 >        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
711 >        assertEquals(0, lock.getQueueLength());
712 >        lock.acquireUninterruptibly();
713 >        t1.start();
714 >        Thread.sleep(SHORT_DELAY_MS);
715 >        assertEquals(1, lock.getQueueLength());
716 >        t2.start();
717 >        Thread.sleep(SHORT_DELAY_MS);
718 >        assertEquals(2, lock.getQueueLength());
719 >        t1.interrupt();
720 >        Thread.sleep(SHORT_DELAY_MS);
721 >        assertEquals(1, lock.getQueueLength());
722 >        lock.release();
723 >        Thread.sleep(SHORT_DELAY_MS);
724 >        assertEquals(0, lock.getQueueLength());
725 >        t1.join();
726 >        t2.join();
727 >    }
728 >
729 >
730 >    /**
731 >     * a deserialized serialized semaphore has same number of permits
732 >     */
733 >    public void testSerialization_fair() throws Exception {
734 >        Semaphore l = new Semaphore(3, true);
735 >
736 >        l.acquire();
737 >        l.release();
738 >        ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
739 >        ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
740 >        out.writeObject(l);
741 >        out.close();
742 >
743 >        ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
744 >        ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
745 >        Semaphore r = (Semaphore) in.readObject();
746 >        assertEquals(3, r.availablePermits());
747 >        assertTrue(r.isFair());
748 >        r.acquire();
749 >        r.release();
750 >    }
751 >
752 >    /**
753 >     * toString indicates current number of permits
754 >     */
755 >    public void testToString() {
756 >        Semaphore s = new Semaphore(0);
757 >        String us = s.toString();
758 >        assertTrue(us.indexOf("Permits = 0") >= 0);
759 >        s.release();
760 >        String s1 = s.toString();
761 >        assertTrue(s1.indexOf("Permits = 1") >= 0);
762 >        s.release();
763 >        String s2 = s.toString();
764 >        assertTrue(s2.indexOf("Permits = 2") >= 0);
765      }
766  
767   }

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