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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 1.23 by jsr166, Tue Dec 1 06:28:44 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 >     * 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 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 <        Semaphore s0 = new Semaphore(0);
67 <        assertEquals(0, s0.availablePermits());
68 <        Semaphore s1 = new Semaphore(-1);
69 <        assertEquals(-1, s1.availablePermits());
70 <        Semaphore s2 = new Semaphore(-1);
71 <        assertEquals(-1, s2.availablePermits());
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 >        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 sufficent permits, else fails
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 45 | Line 98 | public class SemaphoreTest extends JSR16
98      /**
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());
62 <        } catch( InterruptedException e){
63 <            unexpectedException();
64 <        }
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 <        Semaphore s = new Semaphore(1);
123 <        try {
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());
85 <        } finally {
86 <        }
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 <        Semaphore s = new Semaphore(1);
143 <        try {
144 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
145 <            s.release();
146 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
147 <            s.release();
148 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
149 <            s.release();
150 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
151 <            s.release();
152 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
153 <            s.release();
154 <            assertEquals(1, s.availablePermits());
107 <        } catch( InterruptedException e){
108 <            unexpectedException();
109 <        }
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 <        final Semaphore s = new Semaphore(0);
162 <        Thread t = new Thread(new Runnable() {
163 <                public void run() {
164 <                    try {
165 <                        s.acquire();
166 <                        s.release();
167 <                        s.release();
168 <                        s.acquire();
169 <                    } catch(InterruptedException ie){
170 <                        threadUnexpectedException();
171 <                    }
172 <                }
173 <            });
174 <        try {
175 <            t.start();
176 <            Thread.sleep(SHORT_DELAY_MS);
177 <            s.release();
178 <            s.release();
134 <            s.acquire();
135 <            s.acquire();
136 <            s.release();
137 <            t.join();
138 <        } catch( InterruptedException e){
139 <            unexpectedException();
140 <        }
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 <        final Semaphore s = new Semaphore(0);
186 <        Thread t = new Thread(new Runnable() {
187 <                public void run() {
188 <                    s.acquireUninterruptibly();
189 <                    s.release();
190 <                    s.release();
191 <                    s.acquireUninterruptibly();
192 <                }
193 <            });
194 <        try {
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();
165 <        } catch( InterruptedException e){
166 <            unexpectedException();
167 <        }
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 <        final Semaphore s = new Semaphore(1);
211 <        Thread t = new Thread(new Runnable() {
212 <                public void run() {
213 <                    try {
214 <                        s.release();
215 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
216 <                        s.release();
217 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
218 <
219 <                    } catch(InterruptedException ie){
220 <                        threadUnexpectedException();
221 <                    }
222 <                }
223 <            });
224 <        try {
225 <            t.start();
226 <            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 <        }
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 >                assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
216 >                s.release();
217 >                assertTrue(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 <        final Semaphore s = new Semaphore(0);
234 <        Thread t = new Thread(new Runnable() {
235 <                public void run() {
236 <                    try {
237 <                        s.acquire();
238 <                        threadShouldThrow();
239 <                    } catch(InterruptedException success){}
240 <                }
241 <            });
242 <        t.start();
243 <        try {
217 <            Thread.sleep(SHORT_DELAY_MS);
218 <            t.interrupt();
219 <            t.join();
220 <        } catch(InterruptedException e){
221 <            unexpectedException();
222 <        }
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 <    
245 >
246      /**
247       *  A waiting timed acquire blocks interruptibly
248       */
249 <    public void testTryAcquire_InterruptedException() {
250 <        final Semaphore s = new Semaphore(0);
251 <        Thread t = new Thread(new Runnable() {
252 <                public void run() {
253 <                    try {
254 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
255 <                        threadShouldThrow();
256 <                    } catch(InterruptedException success){
257 <                    }
258 <                }
259 <            });
260 <        t.start();
261 <        try {
262 <            Thread.sleep(SHORT_DELAY_MS);
263 <            t.interrupt();
264 <            t.join();
265 <        } catch(InterruptedException e){
266 <            unexpectedException();
267 <        }
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() {
371 <        Semaphore l = new Semaphore(3);
372 <        try {
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 <            r.acquire();
385 <            r.release();
386 <        } catch(Exception e){
387 <            unexpectedException();
388 <        }
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 >                assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
598 >                assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
599 >                assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
600 >                assertTrue(s.tryAcquire(SHORT_DELAY_MS, MILLISECONDS));
601 >                assertTrue(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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