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Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.6 by dl, Mon Nov 3 13:50:07 2003 UTC vs.
Revision 1.45 by jsr166, Tue Aug 13 00:46:27 2019 UTC

# Line 1 | Line 1
1   /*
2 < * Written by members of JCP JSR-166 Expert Group and released to the
3 < * public domain. Use, modify, and redistribute this code in any way
4 < * without acknowledgement. Other contributors include Andrew Wright,
5 < * Jeffrey Hayes, Pat Fischer, Mike Judd.
2 > * Written by Doug Lea with assistance from members of JCP JSR-166
3 > * Expert Group and released to the public domain, as explained at
4 > * http://creativecommons.org/publicdomain/zero/1.0/
5 > * Other contributors include Andrew Wright, Jeffrey Hayes,
6 > * Pat Fisher, Mike Judd.
7   */
8  
9 < import junit.framework.*;
10 < import java.util.*;
11 < import java.util.concurrent.*;
12 < import java.io.*;
9 > import static java.util.concurrent.TimeUnit.MILLISECONDS;
10 >
11 > import java.util.Collection;
12 > import java.util.concurrent.CountDownLatch;
13 > import java.util.concurrent.Semaphore;
14 >
15 > import junit.framework.Test;
16 > import junit.framework.TestSuite;
17  
18   public class SemaphoreTest extends JSR166TestCase {
19      public static void main(String[] args) {
20 <        junit.textui.TestRunner.run (suite());  
20 >        main(suite(), args);
21      }
22      public static Test suite() {
23 <        return new TestSuite(SemaphoreTest.class);
23 >        return new TestSuite(SemaphoreTest.class);
24      }
25  
26      /**
27       * Subclass to expose protected methods
28       */
29      static class PublicSemaphore extends Semaphore {
30 <        PublicSemaphore(int p, boolean f) { super(p, f); }
31 <        public Collection<Thread> getQueuedThreads() {
32 <            return super.getQueuedThreads();
30 >        PublicSemaphore(int permits) { super(permits); }
31 >        PublicSemaphore(int permits, boolean fair) { super(permits, fair); }
32 >        public Collection<Thread> getQueuedThreads() {
33 >            return super.getQueuedThreads();
34          }
35 <        public void reducePermits(int p) {
36 <            super.reducePermits(p);
35 >        public boolean hasQueuedThread(Thread t) {
36 >            return super.getQueuedThreads().contains(t);
37 >        }
38 >        public void reducePermits(int reduction) {
39 >            super.reducePermits(reduction);
40          }
41      }
42  
43      /**
44       * A runnable calling acquire
45       */
46 <    class InterruptibleLockRunnable implements Runnable {
46 >    class InterruptibleLockRunnable extends CheckedRunnable {
47          final Semaphore lock;
48 <        InterruptibleLockRunnable(Semaphore l) { lock = l; }
49 <        public void run() {
48 >        InterruptibleLockRunnable(Semaphore s) { lock = s; }
49 >        public void realRun() {
50              try {
51                  lock.acquire();
52 <            } catch(InterruptedException success){}
52 >            }
53 >            catch (InterruptedException ignored) {}
54          }
55      }
56  
47
57      /**
58 <     * A runnable calling acquire that expects to be
50 <     * interrupted
58 >     * A runnable calling acquire that expects to be interrupted
59       */
60 <    class InterruptedLockRunnable implements Runnable {
60 >    class InterruptedLockRunnable extends CheckedInterruptedRunnable {
61          final Semaphore lock;
62 <        InterruptedLockRunnable(Semaphore l) { lock = l; }
63 <        public void run() {
64 <            try {
65 <                lock.acquire();
66 <                threadShouldThrow();
67 <            } catch(InterruptedException success){}
62 >        InterruptedLockRunnable(Semaphore s) { lock = s; }
63 >        public void realRun() throws InterruptedException {
64 >            lock.acquire();
65 >        }
66 >    }
67 >
68 >    /**
69 >     * Spin-waits until s.hasQueuedThread(t) becomes true.
70 >     */
71 >    void waitForQueuedThread(PublicSemaphore s, Thread t) {
72 >        long startTime = System.nanoTime();
73 >        while (!s.hasQueuedThread(t)) {
74 >            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
75 >                throw new AssertionError("timed out");
76 >            Thread.yield();
77 >        }
78 >        assertTrue(s.hasQueuedThreads());
79 >        assertTrue(t.isAlive());
80 >    }
81 >
82 >    /**
83 >     * Spin-waits until s.hasQueuedThreads() becomes true.
84 >     */
85 >    void waitForQueuedThreads(Semaphore s) {
86 >        long startTime = System.nanoTime();
87 >        while (!s.hasQueuedThreads()) {
88 >            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
89 >                throw new AssertionError("timed out");
90 >            Thread.yield();
91 >        }
92 >    }
93 >
94 >    enum AcquireMethod {
95 >        acquire() {
96 >            void acquire(Semaphore s) throws InterruptedException {
97 >                s.acquire();
98 >            }
99 >        },
100 >        acquireN() {
101 >            void acquire(Semaphore s, int permits) throws InterruptedException {
102 >                s.acquire(permits);
103 >            }
104 >        },
105 >        acquireUninterruptibly() {
106 >            void acquire(Semaphore s) {
107 >                s.acquireUninterruptibly();
108 >            }
109 >        },
110 >        acquireUninterruptiblyN() {
111 >            void acquire(Semaphore s, int permits) {
112 >                s.acquireUninterruptibly(permits);
113 >            }
114 >        },
115 >        tryAcquire() {
116 >            void acquire(Semaphore s) {
117 >                assertTrue(s.tryAcquire());
118 >            }
119 >        },
120 >        tryAcquireN() {
121 >            void acquire(Semaphore s, int permits) {
122 >                assertTrue(s.tryAcquire(permits));
123 >            }
124 >        },
125 >        tryAcquireTimed() {
126 >            void acquire(Semaphore s) throws InterruptedException {
127 >                assertTrue(s.tryAcquire(2 * LONG_DELAY_MS, MILLISECONDS));
128 >            }
129 >            Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
130 >        },
131 >        tryAcquireTimedN {
132 >            void acquire(Semaphore s, int permits) throws InterruptedException {
133 >                assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS));
134 >            }
135 >            Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
136 >        };
137 >
138 >        // Intentionally meta-circular
139 >
140 >        /** Acquires 1 permit. */
141 >        void acquire(Semaphore s) throws InterruptedException {
142 >            acquire(s, 1);
143 >        }
144 >        /** Acquires the given number of permits. */
145 >        void acquire(Semaphore s, int permits) throws InterruptedException {
146 >            for (int i = 0; i < permits; i++)
147 >                acquire(s);
148          }
149 +        Thread.State parkedState() { return Thread.State.WAITING; }
150      }
151  
152      /**
153       * Zero, negative, and positive initial values are allowed in constructor
154       */
155 <    public void testConstructor() {
156 <        Semaphore s0 = new Semaphore(0, false);
157 <        assertEquals(0, s0.availablePermits());
158 <        assertFalse(s0.isFair());
159 <        Semaphore s1 = new Semaphore(-1, false);
160 <        assertEquals(-1, s1.availablePermits());
161 <        Semaphore s2 = new Semaphore(-1, false);
162 <        assertEquals(-1, s2.availablePermits());
155 >    public void testConstructor()      { testConstructor(false); }
156 >    public void testConstructor_fair() { testConstructor(true); }
157 >    public void testConstructor(boolean fair) {
158 >        for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
159 >            Semaphore s = new Semaphore(permits, fair);
160 >            assertEquals(permits, s.availablePermits());
161 >            assertEquals(fair, s.isFair());
162 >        }
163 >    }
164 >
165 >    /**
166 >     * Constructor without fairness argument behaves as nonfair
167 >     */
168 >    public void testConstructorDefaultsToNonFair() {
169 >        for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
170 >            Semaphore s = new Semaphore(permits);
171 >            assertEquals(permits, s.availablePermits());
172 >            assertFalse(s.isFair());
173 >        }
174      }
175  
176      /**
177 <     * tryAcquire succeeds when sufficent permits, else fails
177 >     * tryAcquire succeeds when sufficient permits, else fails
178       */
179 <    public void testTryAcquireInSameThread() {
180 <        Semaphore s = new Semaphore(2, false);
179 >    public void testTryAcquireInSameThread()      { testTryAcquireInSameThread(false); }
180 >    public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); }
181 >    public void testTryAcquireInSameThread(boolean fair) {
182 >        Semaphore s = new Semaphore(2, fair);
183          assertEquals(2, s.availablePermits());
184          assertTrue(s.tryAcquire());
185          assertTrue(s.tryAcquire());
186          assertEquals(0, s.availablePermits());
187          assertFalse(s.tryAcquire());
188 +        assertFalse(s.tryAcquire());
189 +        assertEquals(0, s.availablePermits());
190      }
191  
192      /**
193 <     * Acquire and release of semaphore succeed if initially available
193 >     * timed tryAcquire times out
194       */
195 <    public void testAcquireReleaseInSameThread() {
196 <        Semaphore s = new Semaphore(1, false);
197 <        try {
198 <            s.acquire();
199 <            s.release();
200 <            s.acquire();
201 <            s.release();
202 <            s.acquire();
203 <            s.release();
204 <            s.acquire();
205 <            s.release();
206 <            s.acquire();
207 <            s.release();
208 <            assertEquals(1, s.availablePermits());
209 <        } catch( InterruptedException e){
210 <            unexpectedException();
195 >    public void testTryAcquire_timeout() throws InterruptedException {
196 >        final boolean fair = randomBoolean();
197 >        final Semaphore s = new Semaphore(0, fair);
198 >        final long startTime = System.nanoTime();
199 >        assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS));
200 >        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
201 >    }
202 >
203 >    /**
204 >     * timed tryAcquire(N) times out
205 >     */
206 >    public void testTryAcquireN_timeout() throws InterruptedException {
207 >        final boolean fair = randomBoolean();
208 >        final Semaphore s = new Semaphore(2, fair);
209 >        final long startTime = System.nanoTime();
210 >        assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS));
211 >        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
212 >    }
213 >
214 >    /**
215 >     * acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
216 >     * are interruptible
217 >     */
218 >    public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
219 >    public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
220 >    public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
221 >    public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
222 >    public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
223 >    public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
224 >    public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
225 >    public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
226 >    public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
227 >        final PublicSemaphore s = new PublicSemaphore(0, fair);
228 >        final java.util.concurrent.CyclicBarrier pleaseInterrupt
229 >            = new java.util.concurrent.CyclicBarrier(2);
230 >        Thread t = newStartedThread(new CheckedRunnable() {
231 >            public void realRun() {
232 >                // Interrupt before acquire
233 >                Thread.currentThread().interrupt();
234 >                try {
235 >                    acquirer.acquire(s);
236 >                    shouldThrow();
237 >                } catch (InterruptedException success) {}
238 >                assertFalse(Thread.interrupted());
239 >
240 >                // Interrupt before acquire(N)
241 >                Thread.currentThread().interrupt();
242 >                try {
243 >                    acquirer.acquire(s, 3);
244 >                    shouldThrow();
245 >                } catch (InterruptedException success) {}
246 >                assertFalse(Thread.interrupted());
247 >
248 >                // Interrupt during acquire
249 >                await(pleaseInterrupt);
250 >                try {
251 >                    acquirer.acquire(s);
252 >                    shouldThrow();
253 >                } catch (InterruptedException success) {}
254 >                assertFalse(Thread.interrupted());
255 >
256 >                // Interrupt during acquire(N)
257 >                await(pleaseInterrupt);
258 >                try {
259 >                    acquirer.acquire(s, 3);
260 >                    shouldThrow();
261 >                } catch (InterruptedException success) {}
262 >                assertFalse(Thread.interrupted());
263 >            }});
264 >
265 >        for (int n = 2; n-->0; ) {
266 >            await(pleaseInterrupt);
267 >            assertThreadBlocks(t, acquirer.parkedState());
268 >            t.interrupt();
269          }
108    }
270  
271 <    /**
111 <     * Uninterruptible acquire and release of semaphore succeed if
112 <     * initially available
113 <     */
114 <    public void testAcquireUninterruptiblyReleaseInSameThread() {
115 <        Semaphore s = new Semaphore(1, false);
116 <        try {
117 <            s.acquireUninterruptibly();
118 <            s.release();
119 <            s.acquireUninterruptibly();
120 <            s.release();
121 <            s.acquireUninterruptibly();
122 <            s.release();
123 <            s.acquireUninterruptibly();
124 <            s.release();
125 <            s.acquireUninterruptibly();
126 <            s.release();
127 <            assertEquals(1, s.availablePermits());
128 <        } finally {
129 <        }
271 >        awaitTermination(t);
272      }
273  
274      /**
275 <     * Timed Acquire and release of semaphore succeed if
276 <     * initially available
275 >     * acquireUninterruptibly(), acquireUninterruptibly(N) are
276 >     * uninterruptible
277       */
278 <    public void testTimedAcquireReleaseInSameThread() {
279 <        Semaphore s = new Semaphore(1, false);
280 <        try {
281 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
282 <            s.release();
283 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
284 <            s.release();
285 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
286 <            s.release();
287 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
288 <            s.release();
289 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
290 <            s.release();
291 <            assertEquals(1, s.availablePermits());
292 <        } catch( InterruptedException e){
293 <            unexpectedException();
294 <        }
278 >    public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
279 >    public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
280 >    public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
281 >    public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
282 >    public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
283 >        final PublicSemaphore s = new PublicSemaphore(0, fair);
284 >        final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
285 >
286 >        Thread t1 = newStartedThread(new CheckedRunnable() {
287 >            public void realRun() throws InterruptedException {
288 >                // Interrupt before acquire
289 >                pleaseInterrupt.release();
290 >                Thread.currentThread().interrupt();
291 >                acquirer.acquire(s);
292 >                assertTrue(Thread.interrupted());
293 >            }});
294 >
295 >        Thread t2 = newStartedThread(new CheckedRunnable() {
296 >            public void realRun() throws InterruptedException {
297 >                // Interrupt during acquire
298 >                pleaseInterrupt.release();
299 >                acquirer.acquire(s);
300 >                assertTrue(Thread.interrupted());
301 >            }});
302 >
303 >        await(pleaseInterrupt);
304 >        waitForQueuedThread(s, t1);
305 >        waitForQueuedThread(s, t2);
306 >        t2.interrupt();
307 >
308 >        assertThreadBlocks(t1, Thread.State.WAITING);
309 >        assertThreadBlocks(t2, Thread.State.WAITING);
310 >
311 >        s.release(2);
312 >
313 >        awaitTermination(t1);
314 >        awaitTermination(t2);
315 >    }
316 >
317 >    /**
318 >     * hasQueuedThreads reports whether there are waiting threads
319 >     */
320 >    public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
321 >    public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
322 >    public void testHasQueuedThreads(boolean fair) {
323 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
324 >        assertFalse(lock.hasQueuedThreads());
325 >        lock.acquireUninterruptibly();
326 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
327 >        waitForQueuedThread(lock, t1);
328 >        assertTrue(lock.hasQueuedThreads());
329 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
330 >        waitForQueuedThread(lock, t2);
331 >        assertTrue(lock.hasQueuedThreads());
332 >        t1.interrupt();
333 >        awaitTermination(t1);
334 >        assertTrue(lock.hasQueuedThreads());
335 >        lock.release();
336 >        awaitTermination(t2);
337 >        assertFalse(lock.hasQueuedThreads());
338      }
339  
340      /**
341 <     * A release in one thread enables an acquire in another thread
157 <     */
158 <    public void testAcquireReleaseInDifferentThreads() {
159 <        final Semaphore s = new Semaphore(0, false);
160 <        Thread t = new Thread(new Runnable() {
161 <                public void run() {
162 <                    try {
163 <                        s.acquire();
164 <                        s.release();
165 <                        s.release();
166 <                        s.acquire();
167 <                    } catch(InterruptedException ie){
168 <                        threadUnexpectedException();
169 <                    }
170 <                }
171 <            });
172 <        try {
173 <            t.start();
174 <            Thread.sleep(SHORT_DELAY_MS);
175 <            s.release();
176 <            s.release();
177 <            s.acquire();
178 <            s.acquire();
179 <            s.release();
180 <            t.join();
181 <        } catch( InterruptedException e){
182 <            unexpectedException();
183 <        }
184 <    }
185 <
186 <    /**
187 <     * A release in one thread enables an uninterruptible acquire in another thread
341 >     * getQueueLength reports number of waiting threads
342       */
343 <    public void testUninterruptibleAcquireReleaseInDifferentThreads() {
344 <        final Semaphore s = new Semaphore(0, false);
345 <        Thread t = new Thread(new Runnable() {
346 <                public void run() {
347 <                    s.acquireUninterruptibly();
348 <                    s.release();
349 <                    s.release();
350 <                    s.acquireUninterruptibly();
351 <                }
352 <            });
353 <        try {
354 <            t.start();
355 <            Thread.sleep(SHORT_DELAY_MS);
356 <            s.release();
357 <            s.release();
358 <            s.acquireUninterruptibly();
359 <            s.acquireUninterruptibly();
360 <            s.release();
207 <            t.join();
208 <        } catch( InterruptedException e){
209 <            unexpectedException();
210 <        }
343 >    public void testGetQueueLength()      { testGetQueueLength(false); }
344 >    public void testGetQueueLength_fair() { testGetQueueLength(true); }
345 >    public void testGetQueueLength(boolean fair) {
346 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
347 >        assertEquals(0, lock.getQueueLength());
348 >        lock.acquireUninterruptibly();
349 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
350 >        waitForQueuedThread(lock, t1);
351 >        assertEquals(1, lock.getQueueLength());
352 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
353 >        waitForQueuedThread(lock, t2);
354 >        assertEquals(2, lock.getQueueLength());
355 >        t1.interrupt();
356 >        awaitTermination(t1);
357 >        assertEquals(1, lock.getQueueLength());
358 >        lock.release();
359 >        awaitTermination(t2);
360 >        assertEquals(0, lock.getQueueLength());
361      }
362  
213
363      /**
364 <     *  A release in one thread enables a timed acquire in another thread
364 >     * getQueuedThreads includes waiting threads
365       */
366 <    public void testTimedAcquireReleaseInDifferentThreads() {
367 <        final Semaphore s = new Semaphore(1, false);
368 <        Thread t = new Thread(new Runnable() {
369 <                public void run() {
370 <                    try {
371 <                        s.release();
372 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
373 <                        s.release();
374 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
375 <
376 <                    } catch(InterruptedException ie){
377 <                        threadUnexpectedException();
378 <                    }
379 <                }
380 <            });
381 <        try {
382 <            t.start();
383 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
384 <            s.release();
385 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
386 <            s.release();
238 <            s.release();
239 <            t.join();
240 <        } catch( InterruptedException e){
241 <            unexpectedException();
242 <        }
366 >    public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
367 >    public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
368 >    public void testGetQueuedThreads(boolean fair) {
369 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
370 >        assertTrue(lock.getQueuedThreads().isEmpty());
371 >        lock.acquireUninterruptibly();
372 >        assertTrue(lock.getQueuedThreads().isEmpty());
373 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
374 >        waitForQueuedThread(lock, t1);
375 >        assertTrue(lock.getQueuedThreads().contains(t1));
376 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
377 >        waitForQueuedThread(lock, t2);
378 >        assertTrue(lock.getQueuedThreads().contains(t1));
379 >        assertTrue(lock.getQueuedThreads().contains(t2));
380 >        t1.interrupt();
381 >        awaitTermination(t1);
382 >        assertFalse(lock.getQueuedThreads().contains(t1));
383 >        assertTrue(lock.getQueuedThreads().contains(t2));
384 >        lock.release();
385 >        awaitTermination(t2);
386 >        assertTrue(lock.getQueuedThreads().isEmpty());
387      }
388  
389      /**
390 <     * A waiting acquire blocks interruptibly
391 <     */
392 <    public void testAcquire_InterruptedException() {
393 <        final Semaphore s = new Semaphore(0, false);
394 <        Thread t = new Thread(new Runnable() {
395 <                public void run() {
396 <                    try {
397 <                        s.acquire();
398 <                        threadShouldThrow();
399 <                    } catch(InterruptedException success){}
400 <                }
401 <            });
402 <        t.start();
259 <        try {
260 <            Thread.sleep(SHORT_DELAY_MS);
261 <            t.interrupt();
262 <            t.join();
263 <        } catch(InterruptedException e){
264 <            unexpectedException();
265 <        }
266 <    }
267 <    
268 <    /**
269 <     *  A waiting timed acquire blocks interruptibly
270 <     */
271 <    public void testTryAcquire_InterruptedException() {
272 <        final Semaphore s = new Semaphore(0, false);
273 <        Thread t = new Thread(new Runnable() {
274 <                public void run() {
275 <                    try {
276 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
277 <                        threadShouldThrow();
278 <                    } catch(InterruptedException success){
279 <                    }
280 <                }
281 <            });
282 <        t.start();
283 <        try {
284 <            Thread.sleep(SHORT_DELAY_MS);
285 <            t.interrupt();
286 <            t.join();
287 <        } catch(InterruptedException e){
288 <            unexpectedException();
289 <        }
390 >     * drainPermits reports and removes given number of permits
391 >     */
392 >    public void testDrainPermits()      { testDrainPermits(false); }
393 >    public void testDrainPermits_fair() { testDrainPermits(true); }
394 >    public void testDrainPermits(boolean fair) {
395 >        Semaphore s = new Semaphore(0, fair);
396 >        assertEquals(0, s.availablePermits());
397 >        assertEquals(0, s.drainPermits());
398 >        s.release(10);
399 >        assertEquals(10, s.availablePermits());
400 >        assertEquals(10, s.drainPermits());
401 >        assertEquals(0, s.availablePermits());
402 >        assertEquals(0, s.drainPermits());
403      }
404  
405      /**
406 <     * getQueueLength reports number of waiting threads
406 >     * release(-N) throws IllegalArgumentException
407       */
408 <    public void testGetQueueLength() {
409 <        final Semaphore lock = new Semaphore(1, false);
410 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
411 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
408 >    public void testReleaseIAE()      { testReleaseIAE(false); }
409 >    public void testReleaseIAE_fair() { testReleaseIAE(true); }
410 >    public void testReleaseIAE(boolean fair) {
411 >        Semaphore s = new Semaphore(10, fair);
412          try {
413 <            assertEquals(0, lock.getQueueLength());
414 <            lock.acquireUninterruptibly();
415 <            t1.start();
416 <            Thread.sleep(SHORT_DELAY_MS);
304 <            assertEquals(1, lock.getQueueLength());
305 <            t2.start();
306 <            Thread.sleep(SHORT_DELAY_MS);
307 <            assertEquals(2, lock.getQueueLength());
308 <            t1.interrupt();
309 <            Thread.sleep(SHORT_DELAY_MS);
310 <            assertEquals(1, lock.getQueueLength());
311 <            lock.release();
312 <            Thread.sleep(SHORT_DELAY_MS);
313 <            assertEquals(0, lock.getQueueLength());
314 <            t1.join();
315 <            t2.join();
316 <        } catch(Exception e){
317 <            unexpectedException();
318 <        }
319 <    }
413 >            s.release(-1);
414 >            shouldThrow();
415 >        } catch (IllegalArgumentException success) {}
416 >    }
417  
418      /**
419 <     * getQueuedThreads includes waiting threads
419 >     * reducePermits(-N) throws IllegalArgumentException
420       */
421 <    public void testGetQueuedThreads() {
422 <        final PublicSemaphore lock = new PublicSemaphore(1, false);
423 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
424 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
421 >    public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
422 >    public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
423 >    public void testReducePermitsIAE(boolean fair) {
424 >        PublicSemaphore s = new PublicSemaphore(10, fair);
425          try {
426 <            assertTrue(lock.getQueuedThreads().isEmpty());
427 <            lock.acquireUninterruptibly();
428 <            assertTrue(lock.getQueuedThreads().isEmpty());
429 <            t1.start();
333 <            Thread.sleep(SHORT_DELAY_MS);
334 <            assertTrue(lock.getQueuedThreads().contains(t1));
335 <            t2.start();
336 <            Thread.sleep(SHORT_DELAY_MS);
337 <            assertTrue(lock.getQueuedThreads().contains(t1));
338 <            assertTrue(lock.getQueuedThreads().contains(t2));
339 <            t1.interrupt();
340 <            Thread.sleep(SHORT_DELAY_MS);
341 <            assertFalse(lock.getQueuedThreads().contains(t1));
342 <            assertTrue(lock.getQueuedThreads().contains(t2));
343 <            lock.release();
344 <            Thread.sleep(SHORT_DELAY_MS);
345 <            assertTrue(lock.getQueuedThreads().isEmpty());
346 <            t1.join();
347 <            t2.join();
348 <        } catch(Exception e){
349 <            unexpectedException();
350 <        }
351 <    }
352 <
426 >            s.reducePermits(-1);
427 >            shouldThrow();
428 >        } catch (IllegalArgumentException success) {}
429 >    }
430  
431      /**
432       * reducePermits reduces number of permits
433       */
434 <    public void testReducePermits() {
435 <        PublicSemaphore s = new PublicSemaphore(10, false);
434 >    public void testReducePermits()      { testReducePermits(false); }
435 >    public void testReducePermits_fair() { testReducePermits(true); }
436 >    public void testReducePermits(boolean fair) {
437 >        PublicSemaphore s = new PublicSemaphore(10, fair);
438 >        assertEquals(10, s.availablePermits());
439 >        s.reducePermits(0);
440          assertEquals(10, s.availablePermits());
441          s.reducePermits(1);
442          assertEquals(9, s.availablePermits());
443          s.reducePermits(10);
444          assertEquals(-1, s.availablePermits());
445 +        s.reducePermits(10);
446 +        assertEquals(-11, s.availablePermits());
447 +        s.reducePermits(0);
448 +        assertEquals(-11, s.availablePermits());
449      }
450  
451      /**
452 <     * a deserialized serialized semaphore has same number of permits
453 <     */
369 <    public void testSerialization() {
370 <        Semaphore l = new Semaphore(3, false);
371 <        try {
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 <        } catch(Exception e){
387 <            unexpectedException();
388 <        }
389 <    }
390 <
391 <
392 <    /**
393 <     * Zero, negative, and positive initial values are allowed in constructor
394 <     */
395 <    public void testConstructor_fair() {
396 <        Semaphore s0 = new Semaphore(0, true);
397 <        assertEquals(0, s0.availablePermits());
398 <        assertTrue(s0.isFair());
399 <        Semaphore s1 = new Semaphore(-1, true);
400 <        assertEquals(-1, s1.availablePermits());
401 <        Semaphore s2 = new Semaphore(-1, true);
402 <        assertEquals(-1, s2.availablePermits());
403 <    }
404 <
405 <    /**
406 <     * tryAcquire succeeds when sufficent permits, else fails
407 <     */
408 <    public void testTryAcquireInSameThread_fair() {
409 <        Semaphore s = new Semaphore(2, true);
410 <        assertEquals(2, s.availablePermits());
411 <        assertTrue(s.tryAcquire());
412 <        assertTrue(s.tryAcquire());
413 <        assertEquals(0, s.availablePermits());
414 <        assertFalse(s.tryAcquire());
415 <    }
416 <
417 <    /**
418 <     * tryAcquire(n) succeeds when sufficent permits, else fails
419 <     */
420 <    public void testTryAcquireNInSameThread_fair() {
421 <        Semaphore s = new Semaphore(2, true);
422 <        assertEquals(2, s.availablePermits());
423 <        assertTrue(s.tryAcquire(2));
424 <        assertEquals(0, s.availablePermits());
425 <        assertFalse(s.tryAcquire());
426 <    }
427 <
428 <    /**
429 <     * Acquire and release of semaphore succeed if initially available
452 >     * a reserialized semaphore has same number of permits and
453 >     * fairness, but no queued threads
454       */
455 <    public void testAcquireReleaseInSameThread_fair() {
456 <        Semaphore s = new Semaphore(1, true);
455 >    public void testSerialization()      { testSerialization(false); }
456 >    public void testSerialization_fair() { testSerialization(true); }
457 >    public void testSerialization(boolean fair) {
458          try {
459 +            Semaphore s = new Semaphore(3, fair);
460              s.acquire();
435            s.release();
461              s.acquire();
462              s.release();
438            s.acquire();
439            s.release();
440            s.acquire();
441            s.release();
442            s.acquire();
443            s.release();
444            assertEquals(1, s.availablePermits());
445        } catch( InterruptedException e){
446            unexpectedException();
447        }
448    }
463  
464 <    /**
465 <     * Acquire(n) and release(n) of semaphore succeed if initially available
466 <     */
467 <    public void testAcquireReleaseNInSameThread_fair() {
468 <        Semaphore s = new Semaphore(1, true);
469 <        try {
470 <            s.release(1);
471 <            s.acquire(1);
472 <            s.release(2);
473 <            s.acquire(2);
474 <            s.release(3);
475 <            s.acquire(3);
476 <            s.release(4);
477 <            s.acquire(4);
478 <            s.release(5);
479 <            s.acquire(5);
480 <            assertEquals(1, s.availablePermits());
481 <        } catch( InterruptedException e){
482 <            unexpectedException();
464 >            Semaphore clone = serialClone(s);
465 >            assertEquals(fair, s.isFair());
466 >            assertEquals(fair, clone.isFair());
467 >            assertEquals(2, s.availablePermits());
468 >            assertEquals(2, clone.availablePermits());
469 >            clone.acquire();
470 >            clone.acquire();
471 >            clone.release();
472 >            assertEquals(2, s.availablePermits());
473 >            assertEquals(1, clone.availablePermits());
474 >            assertFalse(s.hasQueuedThreads());
475 >            assertFalse(clone.hasQueuedThreads());
476 >        } catch (InterruptedException e) { threadUnexpectedException(e); }
477 >
478 >        {
479 >            PublicSemaphore s = new PublicSemaphore(0, fair);
480 >            Thread t = newStartedThread(new InterruptibleLockRunnable(s));
481 >            // waitForQueuedThreads(s); // suffers from "flicker", so ...
482 >            waitForQueuedThread(s, t);  // ... we use this instead
483 >            PublicSemaphore clone = serialClone(s);
484 >            assertEquals(fair, s.isFair());
485 >            assertEquals(fair, clone.isFair());
486 >            assertEquals(0, s.availablePermits());
487 >            assertEquals(0, clone.availablePermits());
488 >            assertTrue(s.hasQueuedThreads());
489 >            assertFalse(clone.hasQueuedThreads());
490 >            s.release();
491 >            awaitTermination(t);
492 >            assertFalse(s.hasQueuedThreads());
493 >            assertFalse(clone.hasQueuedThreads());
494          }
495      }
496  
497      /**
498 <     * Acquire(n) and release(n) of semaphore succeed if initially available
499 <     */
500 <    public void testAcquireUninterruptiblyReleaseNInSameThread_fair() {
501 <        Semaphore s = new Semaphore(1, true);
502 <        try {
503 <            s.release(1);
504 <            s.acquireUninterruptibly(1);
505 <            s.release(2);
506 <            s.acquireUninterruptibly(2);
507 <            s.release(3);
508 <            s.acquireUninterruptibly(3);
509 <            s.release(4);
510 <            s.acquireUninterruptibly(4);
511 <            s.release(5);
487 <            s.acquireUninterruptibly(5);
488 <            assertEquals(1, s.availablePermits());
489 <        } finally {
490 <        }
498 >     * tryAcquire(n) succeeds when sufficient permits, else fails
499 >     */
500 >    public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
501 >    public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
502 >    public void testTryAcquireNInSameThread(boolean fair) {
503 >        Semaphore s = new Semaphore(2, fair);
504 >        assertEquals(2, s.availablePermits());
505 >        assertFalse(s.tryAcquire(3));
506 >        assertEquals(2, s.availablePermits());
507 >        assertTrue(s.tryAcquire(2));
508 >        assertEquals(0, s.availablePermits());
509 >        assertFalse(s.tryAcquire(1));
510 >        assertFalse(s.tryAcquire(2));
511 >        assertEquals(0, s.availablePermits());
512      }
513  
514      /**
515 <     * release(n) in one thread enables timed acquire(n) in another thread
515 >     * acquire succeeds if permits available
516       */
517 <    public void testTimedAcquireReleaseNInSameThread_fair() {
518 <        Semaphore s = new Semaphore(1, true);
519 <        try {
520 <            s.release(1);
521 <            assertTrue(s.tryAcquire(1, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
522 <            s.release(2);
523 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
524 <            s.release(3);
525 <            assertTrue(s.tryAcquire(3, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
526 <            s.release(4);
527 <            assertTrue(s.tryAcquire(4, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
528 <            s.release(5);
529 <            assertTrue(s.tryAcquire(5, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
517 >    public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
518 >    public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
519 >    public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
520 >    public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
521 >    public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
522 >    public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
523 >    public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
524 >    public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
525 >    public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
526 >    public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
527 >    public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
528 >    public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
529 >    public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
530 >    public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
531 >    public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
532 >    public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
533 >    public void testReleaseAcquireSameThread(boolean fair,
534 >                                             final AcquireMethod acquirer) {
535 >        Semaphore s = new Semaphore(1, fair);
536 >        for (int i = 1; i < 6; i++) {
537 >            s.release(i);
538 >            assertEquals(1 + i, s.availablePermits());
539 >            try {
540 >                acquirer.acquire(s, i);
541 >            } catch (InterruptedException e) { threadUnexpectedException(e); }
542              assertEquals(1, s.availablePermits());
510        } catch( InterruptedException e){
511            unexpectedException();
543          }
544      }
545  
546      /**
547 <     * release in one thread enables timed acquire in another thread
547 >     * release in one thread enables acquire in another thread
548       */
549 <    public void testTimedAcquireReleaseInSameThread_fair() {
550 <        Semaphore s = new Semaphore(1, true);
551 <        try {
552 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
553 <            s.release();
554 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
555 <            s.release();
556 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
557 <            s.release();
558 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
559 <            s.release();
560 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
561 <            s.release();
562 <            assertEquals(1, s.availablePermits());
563 <        } catch( InterruptedException e){
564 <            unexpectedException();
565 <        }
566 <    }
567 <
568 <    /**
569 <     * A release in one thread enables an acquire in another thread
570 <     */
571 <    public void testAcquireReleaseInDifferentThreads_fair() {
572 <        final Semaphore s = new Semaphore(0, true);
573 <        Thread t = new Thread(new Runnable() {
574 <                public void run() {
575 <                    try {
576 <                        s.acquire();
577 <                        s.acquire();
578 <                        s.acquire();
579 <                        s.acquire();
580 <                    } catch(InterruptedException ie){
581 <                        threadUnexpectedException();
582 <                    }
583 <                }
553 <            });
554 <        try {
555 <            t.start();
556 <            Thread.sleep(SHORT_DELAY_MS);
557 <            s.release();
558 <            s.release();
559 <            s.release();
560 <            s.release();
561 <            s.release();
562 <            s.release();
563 <            t.join();
564 <            assertEquals(2, s.availablePermits());
565 <        } catch( InterruptedException e){
566 <            unexpectedException();
549 >    public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
550 >    public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
551 >    public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
552 >    public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
553 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
554 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
555 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
556 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
557 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
558 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
559 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
560 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
561 >    public void testReleaseAcquireDifferentThreads(boolean fair,
562 >                                                   final AcquireMethod acquirer) {
563 >        final Semaphore s = new Semaphore(0, fair);
564 >        final int rounds = 4;
565 >        long startTime = System.nanoTime();
566 >        Thread t = newStartedThread(new CheckedRunnable() {
567 >            public void realRun() throws InterruptedException {
568 >                for (int i = 0; i < rounds; i++) {
569 >                    assertFalse(s.hasQueuedThreads());
570 >                    if (i % 2 == 0)
571 >                        acquirer.acquire(s);
572 >                    else
573 >                        acquirer.acquire(s, 3);
574 >                }}});
575 >
576 >        for (int i = 0; i < rounds; i++) {
577 >            while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
578 >                Thread.yield();
579 >            assertTrue(t.isAlive());
580 >            if (i % 2 == 0)
581 >                s.release();
582 >            else
583 >                s.release(3);
584          }
585 +        awaitTermination(t);
586 +        assertEquals(0, s.availablePermits());
587 +        assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
588      }
589  
590      /**
591 <     * release(n) in one thread enables acquire(n) in another thread
591 >     * fair locks are strictly FIFO
592       */
593 <    public void testAcquireReleaseNInDifferentThreads_fair() {
594 <        final Semaphore s = new Semaphore(0, true);
595 <        Thread t = new Thread(new Runnable() {
596 <                public void run() {
597 <                    try {
598 <                        s.acquire(2);
599 <                        s.acquire(2);
600 <                        s.release(4);
601 <                    } catch(InterruptedException ie){
602 <                        threadUnexpectedException();
603 <                    }
604 <                }
605 <            });
606 <        try {
607 <            t.start();
608 <            Thread.sleep(SHORT_DELAY_MS);
609 <            s.release(6);
610 <            s.acquire(2);
611 <            s.acquire(2);
612 <            s.release(2);
613 <            t.join();
614 <        } catch( InterruptedException e){
615 <            unexpectedException();
616 <        }
617 <    }
618 <
619 <
620 <
621 <    /**
622 <     * release in one thread enables timed acquire in another thread
623 <     */
624 <    public void testTimedAcquireReleaseInDifferentThreads_fair() {
625 <        final Semaphore s = new Semaphore(1, true);
626 <        Thread t = new Thread(new Runnable() {
627 <                public void run() {
628 <                    try {
629 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
610 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
611 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
612 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
613 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
614 <
615 <                    } catch(InterruptedException ie){
616 <                        threadUnexpectedException();
617 <                    }
618 <                }
619 <            });
620 <        t.start();
621 <        try {
622 <            s.release();
623 <            s.release();
624 <            s.release();
625 <            s.release();
626 <            s.release();
627 <            t.join();
628 <        } catch( InterruptedException e){
629 <            unexpectedException();
630 <        }
631 <    }
632 <
633 <    /**
634 <     * release(n) in one thread enables timed acquire(n) in another thread
635 <     */
636 <    public void testTimedAcquireReleaseNInDifferentThreads_fair() {
637 <        final Semaphore s = new Semaphore(2, true);
638 <        Thread t = new Thread(new Runnable() {
639 <                public void run() {
640 <                    try {
641 <                        threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
642 <                        s.release(2);
643 <                        threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
644 <                        s.release(2);
645 <                    } catch(InterruptedException ie){
646 <                        threadUnexpectedException();
647 <                    }
648 <                }
649 <            });
650 <        t.start();
651 <        try {
652 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
653 <            s.release(2);
654 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
655 <            s.release(2);
656 <            t.join();
657 <        } catch( InterruptedException e){
658 <            unexpectedException();
659 <        }
660 <    }
661 <
662 <    /**
663 <     * A waiting acquire blocks interruptibly
664 <     */
665 <    public void testAcquire_InterruptedException_fair() {
666 <        final Semaphore s = new Semaphore(0, true);
667 <        Thread t = new Thread(new Runnable() {
668 <                public void run() {
669 <                    try {
670 <                        s.acquire();
671 <                        threadShouldThrow();
672 <                    } catch(InterruptedException success){}
673 <                }
674 <            });
675 <        t.start();
676 <        try {
677 <            Thread.sleep(SHORT_DELAY_MS);
678 <            t.interrupt();
679 <            t.join();
680 <        } catch(InterruptedException e){
681 <            unexpectedException();
682 <        }
683 <    }
684 <
685 <    /**
686 <     * A waiting acquire(n) blocks interruptibly
687 <     */
688 <    public void testAcquireN_InterruptedException_fair() {
689 <        final Semaphore s = new Semaphore(2, true);
690 <        Thread t = new Thread(new Runnable() {
691 <                public void run() {
692 <                    try {
693 <                        s.acquire(3);
694 <                        threadShouldThrow();
695 <                    } catch(InterruptedException success){}
696 <                }
697 <            });
698 <        t.start();
699 <        try {
700 <            Thread.sleep(SHORT_DELAY_MS);
701 <            t.interrupt();
702 <            t.join();
703 <        } catch(InterruptedException e){
704 <            unexpectedException();
705 <        }
706 <    }
707 <    
708 <    /**
709 <     *  A waiting tryAcquire blocks interruptibly
710 <     */
711 <    public void testTryAcquire_InterruptedException_fair() {
712 <        final Semaphore s = new Semaphore(0, true);
713 <        Thread t = new Thread(new Runnable() {
714 <                public void run() {
715 <                    try {
716 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
717 <                        threadShouldThrow();
718 <                    } catch(InterruptedException success){
719 <                    }
720 <                }
721 <            });
722 <        t.start();
723 <        try {
724 <            Thread.sleep(SHORT_DELAY_MS);
725 <            t.interrupt();
726 <            t.join();
727 <        } catch(InterruptedException e){
728 <            unexpectedException();
729 <        }
730 <    }
731 <
732 <    /**
733 <     *  A waiting tryAcquire(n) blocks interruptibly
734 <     */
735 <    public void testTryAcquireN_InterruptedException_fair() {
736 <        final Semaphore s = new Semaphore(1, true);
737 <        Thread t = new Thread(new Runnable() {
738 <                public void run() {
739 <                    try {
740 <                        s.tryAcquire(4, MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
741 <                        threadShouldThrow();
742 <                    } catch(InterruptedException success){
743 <                    }
744 <                }
745 <            });
746 <        t.start();
747 <        try {
748 <            Thread.sleep(SHORT_DELAY_MS);
749 <            t.interrupt();
750 <            t.join();
751 <        } catch(InterruptedException e){
752 <            unexpectedException();
753 <        }
593 >    public void testFairLocksFifo() {
594 >        final PublicSemaphore s = new PublicSemaphore(1, true);
595 >        final CountDownLatch pleaseRelease = new CountDownLatch(1);
596 >        Thread t1 = newStartedThread(new CheckedRunnable() {
597 >            public void realRun() throws InterruptedException {
598 >                // Will block; permits are available, but not three
599 >                s.acquire(3);
600 >            }});
601 >
602 >        waitForQueuedThread(s, t1);
603 >
604 >        Thread t2 = newStartedThread(new CheckedRunnable() {
605 >            public void realRun() throws InterruptedException {
606 >                // Will fail, even though 1 permit is available
607 >                assertFalse(
608 >                    s.tryAcquire(randomExpiredTimeout(), randomTimeUnit()));
609 >                assertFalse(
610 >                    s.tryAcquire(1, randomExpiredTimeout(), randomTimeUnit()));
611 >
612 >                // untimed tryAcquire will barge and succeed
613 >                assertTrue(s.tryAcquire());
614 >                s.release(2);
615 >                assertTrue(s.tryAcquire(2));
616 >                s.release();
617 >
618 >                pleaseRelease.countDown();
619 >                // Will queue up behind t1, even though 1 permit is available
620 >                s.acquire();
621 >            }});
622 >
623 >        await(pleaseRelease);
624 >        waitForQueuedThread(s, t2);
625 >        s.release(2);
626 >        awaitTermination(t1);
627 >        assertTrue(t2.isAlive());
628 >        s.release();
629 >        awaitTermination(t2);
630      }
631  
632      /**
633 <     * getQueueLength reports number of waiting threads
634 <     */
635 <    public void testGetQueueLength_fair() {
636 <        final Semaphore lock = new Semaphore(1, true);
637 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
638 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
639 <        try {
640 <            assertEquals(0, lock.getQueueLength());
641 <            lock.acquireUninterruptibly();
642 <            t1.start();
643 <            Thread.sleep(SHORT_DELAY_MS);
644 <            assertEquals(1, lock.getQueueLength());
645 <            t2.start();
770 <            Thread.sleep(SHORT_DELAY_MS);
771 <            assertEquals(2, lock.getQueueLength());
772 <            t1.interrupt();
773 <            Thread.sleep(SHORT_DELAY_MS);
774 <            assertEquals(1, lock.getQueueLength());
775 <            lock.release();
776 <            Thread.sleep(SHORT_DELAY_MS);
777 <            assertEquals(0, lock.getQueueLength());
778 <            t1.join();
779 <            t2.join();
780 <        } catch(Exception e){
781 <            unexpectedException();
782 <        }
783 <    }
784 <
785 <
786 <    /**
787 <     * a deserialized serialized semaphore has same number of permits
788 <     */
789 <    public void testSerialization_fair() {
790 <        Semaphore l = new Semaphore(3, true);
791 <
792 <        try {
793 <            l.acquire();
794 <            l.release();
795 <            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
796 <            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
797 <            out.writeObject(l);
798 <            out.close();
799 <
800 <            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
801 <            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
802 <            Semaphore r = (Semaphore) in.readObject();
803 <            assertEquals(3, r.availablePermits());
804 <            assertTrue(r.isFair());
805 <            r.acquire();
806 <            r.release();
807 <        } catch(Exception e){
808 <            unexpectedException();
809 <        }
633 >     * toString indicates current number of permits
634 >     */
635 >    public void testToString()      { testToString(false); }
636 >    public void testToString_fair() { testToString(true); }
637 >    public void testToString(boolean fair) {
638 >        PublicSemaphore s = new PublicSemaphore(0, fair);
639 >        assertTrue(s.toString().contains("Permits = 0"));
640 >        s.release();
641 >        assertTrue(s.toString().contains("Permits = 1"));
642 >        s.release(2);
643 >        assertTrue(s.toString().contains("Permits = 3"));
644 >        s.reducePermits(5);
645 >        assertTrue(s.toString().contains("Permits = -2"));
646      }
647  
812
648   }

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