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Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.7 by dl, Sat Dec 27 19:26:43 2003 UTC vs.
Revision 1.39 by jsr166, Sun May 14 03:31:53 2017 UTC

# Line 1 | Line 1
1   /*
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.
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 > import java.util.concurrent.ThreadLocalRandom;
15 >
16 > import junit.framework.AssertionFailedError;
17 > import junit.framework.Test;
18 > import junit.framework.TestSuite;
19  
20   public class SemaphoreTest extends JSR166TestCase {
21      public static void main(String[] args) {
22 <        junit.textui.TestRunner.run (suite());  
22 >        main(suite(), args);
23      }
24      public static Test suite() {
25 <        return new TestSuite(SemaphoreTest.class);
25 >        return new TestSuite(SemaphoreTest.class);
26      }
27  
28      /**
29       * Subclass to expose protected methods
30       */
31      static class PublicSemaphore extends Semaphore {
32 <        PublicSemaphore(int p, boolean f) { super(p, f); }
33 <        public Collection<Thread> getQueuedThreads() {
34 <            return super.getQueuedThreads();
32 >        PublicSemaphore(int permits) { super(permits); }
33 >        PublicSemaphore(int permits, boolean fair) { super(permits, fair); }
34 >        public Collection<Thread> getQueuedThreads() {
35 >            return super.getQueuedThreads();
36 >        }
37 >        public boolean hasQueuedThread(Thread t) {
38 >            return super.getQueuedThreads().contains(t);
39          }
40 <        public void reducePermits(int p) {
41 <            super.reducePermits(p);
40 >        public void reducePermits(int reduction) {
41 >            super.reducePermits(reduction);
42          }
43      }
44  
45      /**
46       * A runnable calling acquire
47       */
48 <    class InterruptibleLockRunnable implements Runnable {
48 >    class InterruptibleLockRunnable extends CheckedRunnable {
49          final Semaphore lock;
50 <        InterruptibleLockRunnable(Semaphore l) { lock = l; }
51 <        public void run() {
50 >        InterruptibleLockRunnable(Semaphore s) { lock = s; }
51 >        public void realRun() {
52              try {
53                  lock.acquire();
54 <            } catch(InterruptedException success){}
54 >            }
55 >            catch (InterruptedException ignored) {}
56          }
57      }
58  
48
59      /**
60 <     * A runnable calling acquire that expects to be
51 <     * interrupted
60 >     * A runnable calling acquire that expects to be interrupted
61       */
62 <    class InterruptedLockRunnable implements Runnable {
62 >    class InterruptedLockRunnable extends CheckedInterruptedRunnable {
63          final Semaphore lock;
64 <        InterruptedLockRunnable(Semaphore l) { lock = l; }
65 <        public void run() {
66 <            try {
67 <                lock.acquire();
68 <                threadShouldThrow();
69 <            } catch(InterruptedException success){}
64 >        InterruptedLockRunnable(Semaphore s) { lock = s; }
65 >        public void realRun() throws InterruptedException {
66 >            lock.acquire();
67 >        }
68 >    }
69 >
70 >    /**
71 >     * Spin-waits until s.hasQueuedThread(t) becomes true.
72 >     */
73 >    void waitForQueuedThread(PublicSemaphore s, Thread t) {
74 >        long startTime = System.nanoTime();
75 >        while (!s.hasQueuedThread(t)) {
76 >            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
77 >                throw new AssertionFailedError("timed out");
78 >            Thread.yield();
79 >        }
80 >        assertTrue(s.hasQueuedThreads());
81 >        assertTrue(t.isAlive());
82 >    }
83 >
84 >    /**
85 >     * Spin-waits until s.hasQueuedThreads() becomes true.
86 >     */
87 >    void waitForQueuedThreads(Semaphore s) {
88 >        long startTime = System.nanoTime();
89 >        while (!s.hasQueuedThreads()) {
90 >            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
91 >                throw new AssertionFailedError("timed out");
92 >            Thread.yield();
93 >        }
94 >    }
95 >
96 >    enum AcquireMethod {
97 >        acquire() {
98 >            void acquire(Semaphore s) throws InterruptedException {
99 >                s.acquire();
100 >            }
101 >        },
102 >        acquireN() {
103 >            void acquire(Semaphore s, int permits) throws InterruptedException {
104 >                s.acquire(permits);
105 >            }
106 >        },
107 >        acquireUninterruptibly() {
108 >            void acquire(Semaphore s) {
109 >                s.acquireUninterruptibly();
110 >            }
111 >        },
112 >        acquireUninterruptiblyN() {
113 >            void acquire(Semaphore s, int permits) {
114 >                s.acquireUninterruptibly(permits);
115 >            }
116 >        },
117 >        tryAcquire() {
118 >            void acquire(Semaphore s) {
119 >                assertTrue(s.tryAcquire());
120 >            }
121 >        },
122 >        tryAcquireN() {
123 >            void acquire(Semaphore s, int permits) {
124 >                assertTrue(s.tryAcquire(permits));
125 >            }
126 >        },
127 >        tryAcquireTimed() {
128 >            void acquire(Semaphore s) throws InterruptedException {
129 >                assertTrue(s.tryAcquire(2 * LONG_DELAY_MS, MILLISECONDS));
130 >            }
131 >            Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
132 >        },
133 >        tryAcquireTimedN {
134 >            void acquire(Semaphore s, int permits) throws InterruptedException {
135 >                assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS));
136 >            }
137 >            Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
138 >        };
139 >
140 >        // Intentionally meta-circular
141 >
142 >        /** Acquires 1 permit. */
143 >        void acquire(Semaphore s) throws InterruptedException {
144 >            acquire(s, 1);
145 >        }
146 >        /** Acquires the given number of permits. */
147 >        void acquire(Semaphore s, int permits) throws InterruptedException {
148 >            for (int i = 0; i < permits; i++)
149 >                acquire(s);
150          }
151 +        Thread.State parkedState() { return Thread.State.WAITING; }
152      }
153  
154      /**
155       * Zero, negative, and positive initial values are allowed in constructor
156       */
157 <    public void testConstructor() {
158 <        Semaphore s0 = new Semaphore(0, false);
159 <        assertEquals(0, s0.availablePermits());
160 <        assertFalse(s0.isFair());
161 <        Semaphore s1 = new Semaphore(-1, false);
162 <        assertEquals(-1, s1.availablePermits());
163 <        Semaphore s2 = new Semaphore(-1, false);
164 <        assertEquals(-1, s2.availablePermits());
157 >    public void testConstructor()      { testConstructor(false); }
158 >    public void testConstructor_fair() { testConstructor(true); }
159 >    public void testConstructor(boolean fair) {
160 >        for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
161 >            Semaphore s = new Semaphore(permits, fair);
162 >            assertEquals(permits, s.availablePermits());
163 >            assertEquals(fair, s.isFair());
164 >        }
165      }
166  
167      /**
168 <     * tryAcquire succeeds when sufficent permits, else fails
168 >     * Constructor without fairness argument behaves as nonfair
169       */
170 <    public void testTryAcquireInSameThread() {
171 <        Semaphore s = new Semaphore(2, false);
170 >    public void testConstructorDefaultsToNonFair() {
171 >        for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
172 >            Semaphore s = new Semaphore(permits);
173 >            assertEquals(permits, s.availablePermits());
174 >            assertFalse(s.isFair());
175 >        }
176 >    }
177 >
178 >    /**
179 >     * tryAcquire succeeds when sufficient permits, else fails
180 >     */
181 >    public void testTryAcquireInSameThread()      { testTryAcquireInSameThread(false); }
182 >    public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); }
183 >    public void testTryAcquireInSameThread(boolean fair) {
184 >        Semaphore s = new Semaphore(2, fair);
185          assertEquals(2, s.availablePermits());
186          assertTrue(s.tryAcquire());
187          assertTrue(s.tryAcquire());
188          assertEquals(0, s.availablePermits());
189          assertFalse(s.tryAcquire());
190 +        assertFalse(s.tryAcquire());
191 +        assertEquals(0, s.availablePermits());
192      }
193  
194      /**
195 <     * Acquire and release of semaphore succeed if initially available
195 >     * timed tryAcquire times out
196       */
197 <    public void testAcquireReleaseInSameThread() {
198 <        Semaphore s = new Semaphore(1, false);
199 <        try {
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 <            s.acquire();
209 <            s.release();
210 <            assertEquals(1, s.availablePermits());
211 <        } catch( InterruptedException e){
212 <            unexpectedException();
197 >    public void testTryAcquire_timeout() {
198 >        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
199 >        final boolean fair = rnd.nextBoolean();
200 >        final Semaphore s = new Semaphore(0, fair);
201 >        final long startTime = System.nanoTime();
202 >        try { assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS)); }
203 >        catch (InterruptedException e) { threadUnexpectedException(e); }
204 >        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
205 >    }
206 >
207 >    /**
208 >     * timed tryAcquire(N) times out
209 >     */
210 >    public void testTryAcquireN_timeout() {
211 >        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
212 >        final boolean fair = rnd.nextBoolean();
213 >        final Semaphore s = new Semaphore(2, fair);
214 >        final long startTime = System.nanoTime();
215 >        try { assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS)); }
216 >        catch (InterruptedException e) { threadUnexpectedException(e); }
217 >        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
218 >    }
219 >
220 >    /**
221 >     * acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
222 >     * are interruptible
223 >     */
224 >    public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
225 >    public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
226 >    public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
227 >    public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
228 >    public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
229 >    public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
230 >    public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
231 >    public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
232 >    public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
233 >        final PublicSemaphore s = new PublicSemaphore(0, fair);
234 >        final java.util.concurrent.CyclicBarrier pleaseInterrupt
235 >            = new java.util.concurrent.CyclicBarrier(2);
236 >        Thread t = newStartedThread(new CheckedRunnable() {
237 >            public void realRun() {
238 >                // Interrupt before acquire
239 >                Thread.currentThread().interrupt();
240 >                try {
241 >                    acquirer.acquire(s);
242 >                    shouldThrow();
243 >                } catch (InterruptedException success) {}
244 >                assertFalse(Thread.interrupted());
245 >
246 >                // Interrupt before acquire(N)
247 >                Thread.currentThread().interrupt();
248 >                try {
249 >                    acquirer.acquire(s, 3);
250 >                    shouldThrow();
251 >                } catch (InterruptedException success) {}
252 >                assertFalse(Thread.interrupted());
253 >
254 >                // Interrupt during acquire
255 >                await(pleaseInterrupt);
256 >                try {
257 >                    acquirer.acquire(s);
258 >                    shouldThrow();
259 >                } catch (InterruptedException success) {}
260 >                assertFalse(Thread.interrupted());
261 >
262 >                // Interrupt during acquire(N)
263 >                await(pleaseInterrupt);
264 >                try {
265 >                    acquirer.acquire(s, 3);
266 >                    shouldThrow();
267 >                } catch (InterruptedException success) {}
268 >                assertFalse(Thread.interrupted());
269 >            }});
270 >
271 >        for (int n = 2; n-->0; ) {
272 >            await(pleaseInterrupt);
273 >            assertThreadBlocks(t, acquirer.parkedState());
274 >            t.interrupt();
275          }
276 +        
277 +        awaitTermination(t);
278      }
279  
280      /**
281 <     * Uninterruptible acquire and release of semaphore succeed if
282 <     * initially available
281 >     * acquireUninterruptibly(), acquireUninterruptibly(N) are
282 >     * uninterruptible
283       */
284 <    public void testAcquireUninterruptiblyReleaseInSameThread() {
285 <        Semaphore s = new Semaphore(1, false);
286 <        try {
287 <            s.acquireUninterruptibly();
288 <            s.release();
289 <            s.acquireUninterruptibly();
290 <            s.release();
291 <            s.acquireUninterruptibly();
292 <            s.release();
293 <            s.acquireUninterruptibly();
294 <            s.release();
295 <            s.acquireUninterruptibly();
296 <            s.release();
297 <            assertEquals(1, s.availablePermits());
298 <        } finally {
299 <        }
284 >    public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
285 >    public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
286 >    public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
287 >    public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
288 >    public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
289 >        final PublicSemaphore s = new PublicSemaphore(0, fair);
290 >        final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
291 >
292 >        Thread t1 = newStartedThread(new CheckedRunnable() {
293 >            public void realRun() throws InterruptedException {
294 >                // Interrupt before acquire
295 >                pleaseInterrupt.release();
296 >                Thread.currentThread().interrupt();
297 >                acquirer.acquire(s);
298 >                assertTrue(Thread.interrupted());
299 >            }});
300 >
301 >        Thread t2 = newStartedThread(new CheckedRunnable() {
302 >            public void realRun() throws InterruptedException {
303 >                // Interrupt during acquire
304 >                pleaseInterrupt.release();
305 >                acquirer.acquire(s);
306 >                assertTrue(Thread.interrupted());
307 >            }});
308 >
309 >        await(pleaseInterrupt);
310 >        waitForQueuedThread(s, t1);
311 >        waitForQueuedThread(s, t2);
312 >        t2.interrupt();
313 >
314 >        assertThreadBlocks(t1, Thread.State.WAITING);
315 >        assertThreadBlocks(t2, Thread.State.WAITING);
316 >
317 >        s.release(2);
318 >
319 >        awaitTermination(t1);
320 >        awaitTermination(t2);
321 >    }
322 >
323 >    /**
324 >     * hasQueuedThreads reports whether there are waiting threads
325 >     */
326 >    public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
327 >    public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
328 >    public void testHasQueuedThreads(boolean fair) {
329 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
330 >        assertFalse(lock.hasQueuedThreads());
331 >        lock.acquireUninterruptibly();
332 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
333 >        waitForQueuedThread(lock, t1);
334 >        assertTrue(lock.hasQueuedThreads());
335 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
336 >        waitForQueuedThread(lock, t2);
337 >        assertTrue(lock.hasQueuedThreads());
338 >        t1.interrupt();
339 >        awaitTermination(t1);
340 >        assertTrue(lock.hasQueuedThreads());
341 >        lock.release();
342 >        awaitTermination(t2);
343 >        assertFalse(lock.hasQueuedThreads());
344      }
345  
346      /**
347 <     * Timed Acquire and release of semaphore succeed if
135 <     * initially available
347 >     * getQueueLength reports number of waiting threads
348       */
349 <    public void testTimedAcquireReleaseInSameThread() {
350 <        Semaphore s = new Semaphore(1, false);
351 <        try {
352 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
353 <            s.release();
354 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
355 <            s.release();
356 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
357 <            s.release();
358 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
359 <            s.release();
360 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
361 <            s.release();
362 <            assertEquals(1, s.availablePermits());
363 <        } catch( InterruptedException e){
364 <            unexpectedException();
365 <        }
349 >    public void testGetQueueLength()      { testGetQueueLength(false); }
350 >    public void testGetQueueLength_fair() { testGetQueueLength(true); }
351 >    public void testGetQueueLength(boolean fair) {
352 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
353 >        assertEquals(0, lock.getQueueLength());
354 >        lock.acquireUninterruptibly();
355 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
356 >        waitForQueuedThread(lock, t1);
357 >        assertEquals(1, lock.getQueueLength());
358 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
359 >        waitForQueuedThread(lock, t2);
360 >        assertEquals(2, lock.getQueueLength());
361 >        t1.interrupt();
362 >        awaitTermination(t1);
363 >        assertEquals(1, lock.getQueueLength());
364 >        lock.release();
365 >        awaitTermination(t2);
366 >        assertEquals(0, lock.getQueueLength());
367      }
368  
369      /**
370 <     * A release in one thread enables an acquire in another thread
370 >     * getQueuedThreads includes waiting threads
371       */
372 <    public void testAcquireReleaseInDifferentThreads() {
373 <        final Semaphore s = new Semaphore(0, false);
374 <        Thread t = new Thread(new Runnable() {
375 <                public void run() {
376 <                    try {
377 <                        s.acquire();
378 <                        s.release();
379 <                        s.release();
380 <                        s.acquire();
381 <                    } catch(InterruptedException ie){
382 <                        threadUnexpectedException();
383 <                    }
384 <                }
385 <            });
386 <        try {
387 <            t.start();
388 <            Thread.sleep(SHORT_DELAY_MS);
389 <            s.release();
390 <            s.release();
391 <            s.acquire();
392 <            s.acquire();
180 <            s.release();
181 <            t.join();
182 <        } catch( InterruptedException e){
183 <            unexpectedException();
184 <        }
372 >    public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
373 >    public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
374 >    public void testGetQueuedThreads(boolean fair) {
375 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
376 >        assertTrue(lock.getQueuedThreads().isEmpty());
377 >        lock.acquireUninterruptibly();
378 >        assertTrue(lock.getQueuedThreads().isEmpty());
379 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
380 >        waitForQueuedThread(lock, t1);
381 >        assertTrue(lock.getQueuedThreads().contains(t1));
382 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
383 >        waitForQueuedThread(lock, t2);
384 >        assertTrue(lock.getQueuedThreads().contains(t1));
385 >        assertTrue(lock.getQueuedThreads().contains(t2));
386 >        t1.interrupt();
387 >        awaitTermination(t1);
388 >        assertFalse(lock.getQueuedThreads().contains(t1));
389 >        assertTrue(lock.getQueuedThreads().contains(t2));
390 >        lock.release();
391 >        awaitTermination(t2);
392 >        assertTrue(lock.getQueuedThreads().isEmpty());
393      }
394  
395      /**
396 <     * A release in one thread enables an uninterruptible acquire in another thread
397 <     */
398 <    public void testUninterruptibleAcquireReleaseInDifferentThreads() {
399 <        final Semaphore s = new Semaphore(0, false);
400 <        Thread t = new Thread(new Runnable() {
401 <                public void run() {
402 <                    s.acquireUninterruptibly();
403 <                    s.release();
404 <                    s.release();
405 <                    s.acquireUninterruptibly();
406 <                }
407 <            });
408 <        try {
201 <            t.start();
202 <            Thread.sleep(SHORT_DELAY_MS);
203 <            s.release();
204 <            s.release();
205 <            s.acquireUninterruptibly();
206 <            s.acquireUninterruptibly();
207 <            s.release();
208 <            t.join();
209 <        } catch( InterruptedException e){
210 <            unexpectedException();
211 <        }
396 >     * drainPermits reports and removes given number of permits
397 >     */
398 >    public void testDrainPermits()      { testDrainPermits(false); }
399 >    public void testDrainPermits_fair() { testDrainPermits(true); }
400 >    public void testDrainPermits(boolean fair) {
401 >        Semaphore s = new Semaphore(0, fair);
402 >        assertEquals(0, s.availablePermits());
403 >        assertEquals(0, s.drainPermits());
404 >        s.release(10);
405 >        assertEquals(10, s.availablePermits());
406 >        assertEquals(10, s.drainPermits());
407 >        assertEquals(0, s.availablePermits());
408 >        assertEquals(0, s.drainPermits());
409      }
410  
214
411      /**
412 <     *  A release in one thread enables a timed acquire in another thread
412 >     * release(-N) throws IllegalArgumentException
413       */
414 <    public void testTimedAcquireReleaseInDifferentThreads() {
415 <        final Semaphore s = new Semaphore(1, false);
416 <        Thread t = new Thread(new Runnable() {
417 <                public void run() {
222 <                    try {
223 <                        s.release();
224 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
225 <                        s.release();
226 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
227 <
228 <                    } catch(InterruptedException ie){
229 <                        threadUnexpectedException();
230 <                    }
231 <                }
232 <            });
414 >    public void testReleaseIAE()      { testReleaseIAE(false); }
415 >    public void testReleaseIAE_fair() { testReleaseIAE(true); }
416 >    public void testReleaseIAE(boolean fair) {
417 >        Semaphore s = new Semaphore(10, fair);
418          try {
419 <            t.start();
420 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
421 <            s.release();
237 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
238 <            s.release();
239 <            s.release();
240 <            t.join();
241 <        } catch( InterruptedException e){
242 <            unexpectedException();
243 <        }
244 <    }
245 <
246 <    /**
247 <     * A waiting acquire blocks interruptibly
248 <     */
249 <    public void testAcquire_InterruptedException() {
250 <        final Semaphore s = new Semaphore(0, false);
251 <        Thread t = new Thread(new Runnable() {
252 <                public void run() {
253 <                    try {
254 <                        s.acquire();
255 <                        threadShouldThrow();
256 <                    } catch(InterruptedException success){}
257 <                }
258 <            });
259 <        t.start();
260 <        try {
261 <            Thread.sleep(SHORT_DELAY_MS);
262 <            t.interrupt();
263 <            t.join();
264 <        } catch(InterruptedException e){
265 <            unexpectedException();
266 <        }
267 <    }
268 <    
269 <    /**
270 <     *  A waiting timed acquire blocks interruptibly
271 <     */
272 <    public void testTryAcquire_InterruptedException() {
273 <        final Semaphore s = new Semaphore(0, false);
274 <        Thread t = new Thread(new Runnable() {
275 <                public void run() {
276 <                    try {
277 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
278 <                        threadShouldThrow();
279 <                    } catch(InterruptedException success){
280 <                    }
281 <                }
282 <            });
283 <        t.start();
284 <        try {
285 <            Thread.sleep(SHORT_DELAY_MS);
286 <            t.interrupt();
287 <            t.join();
288 <        } catch(InterruptedException e){
289 <            unexpectedException();
290 <        }
419 >            s.release(-1);
420 >            shouldThrow();
421 >        } catch (IllegalArgumentException success) {}
422      }
423  
424      /**
425 <     * getQueueLength reports number of waiting threads
295 <     */
296 <    public void testGetQueueLength() {
297 <        final Semaphore lock = new Semaphore(1, false);
298 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
299 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
300 <        try {
301 <            assertEquals(0, lock.getQueueLength());
302 <            lock.acquireUninterruptibly();
303 <            t1.start();
304 <            Thread.sleep(SHORT_DELAY_MS);
305 <            assertEquals(1, lock.getQueueLength());
306 <            t2.start();
307 <            Thread.sleep(SHORT_DELAY_MS);
308 <            assertEquals(2, lock.getQueueLength());
309 <            t1.interrupt();
310 <            Thread.sleep(SHORT_DELAY_MS);
311 <            assertEquals(1, lock.getQueueLength());
312 <            lock.release();
313 <            Thread.sleep(SHORT_DELAY_MS);
314 <            assertEquals(0, lock.getQueueLength());
315 <            t1.join();
316 <            t2.join();
317 <        } catch(Exception e){
318 <            unexpectedException();
319 <        }
320 <    }
321 <
322 <    /**
323 <     * getQueuedThreads includes waiting threads
425 >     * reducePermits(-N) throws IllegalArgumentException
426       */
427 <    public void testGetQueuedThreads() {
428 <        final PublicSemaphore lock = new PublicSemaphore(1, false);
429 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
430 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
427 >    public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
428 >    public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
429 >    public void testReducePermitsIAE(boolean fair) {
430 >        PublicSemaphore s = new PublicSemaphore(10, fair);
431          try {
432 <            assertTrue(lock.getQueuedThreads().isEmpty());
433 <            lock.acquireUninterruptibly();
434 <            assertTrue(lock.getQueuedThreads().isEmpty());
435 <            t1.start();
334 <            Thread.sleep(SHORT_DELAY_MS);
335 <            assertTrue(lock.getQueuedThreads().contains(t1));
336 <            t2.start();
337 <            Thread.sleep(SHORT_DELAY_MS);
338 <            assertTrue(lock.getQueuedThreads().contains(t1));
339 <            assertTrue(lock.getQueuedThreads().contains(t2));
340 <            t1.interrupt();
341 <            Thread.sleep(SHORT_DELAY_MS);
342 <            assertFalse(lock.getQueuedThreads().contains(t1));
343 <            assertTrue(lock.getQueuedThreads().contains(t2));
344 <            lock.release();
345 <            Thread.sleep(SHORT_DELAY_MS);
346 <            assertTrue(lock.getQueuedThreads().isEmpty());
347 <            t1.join();
348 <            t2.join();
349 <        } catch(Exception e){
350 <            unexpectedException();
351 <        }
352 <    }
353 <
432 >            s.reducePermits(-1);
433 >            shouldThrow();
434 >        } catch (IllegalArgumentException success) {}
435 >    }
436  
437      /**
438       * reducePermits reduces number of permits
439       */
440 <    public void testReducePermits() {
441 <        PublicSemaphore s = new PublicSemaphore(10, false);
440 >    public void testReducePermits()      { testReducePermits(false); }
441 >    public void testReducePermits_fair() { testReducePermits(true); }
442 >    public void testReducePermits(boolean fair) {
443 >        PublicSemaphore s = new PublicSemaphore(10, fair);
444 >        assertEquals(10, s.availablePermits());
445 >        s.reducePermits(0);
446          assertEquals(10, s.availablePermits());
447          s.reducePermits(1);
448          assertEquals(9, s.availablePermits());
449          s.reducePermits(10);
450          assertEquals(-1, s.availablePermits());
451 +        s.reducePermits(10);
452 +        assertEquals(-11, s.availablePermits());
453 +        s.reducePermits(0);
454 +        assertEquals(-11, s.availablePermits());
455      }
456  
457      /**
458 <     * a deserialized serialized semaphore has same number of permits
459 <     */
370 <    public void testSerialization() {
371 <        Semaphore l = new Semaphore(3, false);
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 <            assertFalse(r.isFair());
385 <            r.acquire();
386 <            r.release();
387 <        } catch(Exception e){
388 <            unexpectedException();
389 <        }
390 <    }
391 <
392 <
393 <    /**
394 <     * Zero, negative, and positive initial values are allowed in constructor
395 <     */
396 <    public void testConstructor_fair() {
397 <        Semaphore s0 = new Semaphore(0, true);
398 <        assertEquals(0, s0.availablePermits());
399 <        assertTrue(s0.isFair());
400 <        Semaphore s1 = new Semaphore(-1, true);
401 <        assertEquals(-1, s1.availablePermits());
402 <        Semaphore s2 = new Semaphore(-1, true);
403 <        assertEquals(-1, s2.availablePermits());
404 <    }
405 <
406 <    /**
407 <     * tryAcquire succeeds when sufficent permits, else fails
408 <     */
409 <    public void testTryAcquireInSameThread_fair() {
410 <        Semaphore s = new Semaphore(2, true);
411 <        assertEquals(2, s.availablePermits());
412 <        assertTrue(s.tryAcquire());
413 <        assertTrue(s.tryAcquire());
414 <        assertEquals(0, s.availablePermits());
415 <        assertFalse(s.tryAcquire());
416 <    }
417 <
418 <    /**
419 <     * tryAcquire(n) succeeds when sufficent permits, else fails
420 <     */
421 <    public void testTryAcquireNInSameThread_fair() {
422 <        Semaphore s = new Semaphore(2, true);
423 <        assertEquals(2, s.availablePermits());
424 <        assertTrue(s.tryAcquire(2));
425 <        assertEquals(0, s.availablePermits());
426 <        assertFalse(s.tryAcquire());
427 <    }
428 <
429 <    /**
430 <     * Acquire and release of semaphore succeed if initially available
458 >     * a reserialized semaphore has same number of permits and
459 >     * fairness, but no queued threads
460       */
461 <    public void testAcquireReleaseInSameThread_fair() {
462 <        Semaphore s = new Semaphore(1, true);
461 >    public void testSerialization()      { testSerialization(false); }
462 >    public void testSerialization_fair() { testSerialization(true); }
463 >    public void testSerialization(boolean fair) {
464          try {
465 +            Semaphore s = new Semaphore(3, fair);
466              s.acquire();
436            s.release();
437            s.acquire();
438            s.release();
439            s.acquire();
440            s.release();
441            s.acquire();
442            s.release();
467              s.acquire();
468              s.release();
445            assertEquals(1, s.availablePermits());
446        } catch( InterruptedException e){
447            unexpectedException();
448        }
449    }
450
451    /**
452     * Acquire(n) and release(n) of semaphore succeed if initially available
453     */
454    public void testAcquireReleaseNInSameThread_fair() {
455        Semaphore s = new Semaphore(1, true);
456        try {
457            s.release(1);
458            s.acquire(1);
459            s.release(2);
460            s.acquire(2);
461            s.release(3);
462            s.acquire(3);
463            s.release(4);
464            s.acquire(4);
465            s.release(5);
466            s.acquire(5);
467            assertEquals(1, s.availablePermits());
468        } catch( InterruptedException e){
469            unexpectedException();
470        }
471    }
469  
470 <    /**
471 <     * Acquire(n) and release(n) of semaphore succeed if initially available
472 <     */
473 <    public void testAcquireUninterruptiblyReleaseNInSameThread_fair() {
474 <        Semaphore s = new Semaphore(1, true);
475 <        try {
476 <            s.release(1);
477 <            s.acquireUninterruptibly(1);
478 <            s.release(2);
479 <            s.acquireUninterruptibly(2);
480 <            s.release(3);
481 <            s.acquireUninterruptibly(3);
482 <            s.release(4);
483 <            s.acquireUninterruptibly(4);
484 <            s.release(5);
485 <            s.acquireUninterruptibly(5);
486 <            assertEquals(1, s.availablePermits());
487 <        } finally {
470 >            Semaphore clone = serialClone(s);
471 >            assertEquals(fair, s.isFair());
472 >            assertEquals(fair, clone.isFair());
473 >            assertEquals(2, s.availablePermits());
474 >            assertEquals(2, clone.availablePermits());
475 >            clone.acquire();
476 >            clone.acquire();
477 >            clone.release();
478 >            assertEquals(2, s.availablePermits());
479 >            assertEquals(1, clone.availablePermits());
480 >            assertFalse(s.hasQueuedThreads());
481 >            assertFalse(clone.hasQueuedThreads());
482 >        } catch (InterruptedException e) { threadUnexpectedException(e); }
483 >
484 >        {
485 >            PublicSemaphore s = new PublicSemaphore(0, fair);
486 >            Thread t = newStartedThread(new InterruptibleLockRunnable(s));
487 >            // waitForQueuedThreads(s); // suffers from "flicker", so ...
488 >            waitForQueuedThread(s, t);  // ... we use this instead
489 >            PublicSemaphore clone = serialClone(s);
490 >            assertEquals(fair, s.isFair());
491 >            assertEquals(fair, clone.isFair());
492 >            assertEquals(0, s.availablePermits());
493 >            assertEquals(0, clone.availablePermits());
494 >            assertTrue(s.hasQueuedThreads());
495 >            assertFalse(clone.hasQueuedThreads());
496 >            s.release();
497 >            awaitTermination(t);
498 >            assertFalse(s.hasQueuedThreads());
499 >            assertFalse(clone.hasQueuedThreads());
500          }
501      }
502  
503      /**
504 <     * release(n) in one thread enables timed acquire(n) in another thread
505 <     */
506 <    public void testTimedAcquireReleaseNInSameThread_fair() {
507 <        Semaphore s = new Semaphore(1, true);
508 <        try {
509 <            s.release(1);
510 <            assertTrue(s.tryAcquire(1, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
511 <            s.release(2);
512 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
513 <            s.release(3);
514 <            assertTrue(s.tryAcquire(3, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
515 <            s.release(4);
516 <            assertTrue(s.tryAcquire(4, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
517 <            s.release(5);
509 <            assertTrue(s.tryAcquire(5, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
510 <            assertEquals(1, s.availablePermits());
511 <        } catch( InterruptedException e){
512 <            unexpectedException();
513 <        }
504 >     * tryAcquire(n) succeeds when sufficient permits, else fails
505 >     */
506 >    public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
507 >    public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
508 >    public void testTryAcquireNInSameThread(boolean fair) {
509 >        Semaphore s = new Semaphore(2, fair);
510 >        assertEquals(2, s.availablePermits());
511 >        assertFalse(s.tryAcquire(3));
512 >        assertEquals(2, s.availablePermits());
513 >        assertTrue(s.tryAcquire(2));
514 >        assertEquals(0, s.availablePermits());
515 >        assertFalse(s.tryAcquire(1));
516 >        assertFalse(s.tryAcquire(2));
517 >        assertEquals(0, s.availablePermits());
518      }
519  
520      /**
521 <     * release in one thread enables timed acquire in another thread
521 >     * acquire succeeds if permits available
522       */
523 <    public void testTimedAcquireReleaseInSameThread_fair() {
524 <        Semaphore s = new Semaphore(1, true);
525 <        try {
526 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
527 <            s.release();
528 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
529 <            s.release();
530 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
531 <            s.release();
532 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
533 <            s.release();
534 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
535 <            s.release();
523 >    public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
524 >    public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
525 >    public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
526 >    public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
527 >    public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
528 >    public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
529 >    public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
530 >    public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
531 >    public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
532 >    public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
533 >    public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
534 >    public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
535 >    public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
536 >    public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
537 >    public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
538 >    public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
539 >    public void testReleaseAcquireSameThread(boolean fair,
540 >                                             final AcquireMethod acquirer) {
541 >        Semaphore s = new Semaphore(1, fair);
542 >        for (int i = 1; i < 6; i++) {
543 >            s.release(i);
544 >            assertEquals(1 + i, s.availablePermits());
545 >            try {
546 >                acquirer.acquire(s, i);
547 >            } catch (InterruptedException e) { threadUnexpectedException(e); }
548              assertEquals(1, s.availablePermits());
533        } catch( InterruptedException e){
534            unexpectedException();
549          }
550      }
551  
552      /**
553 <     * A release in one thread enables an acquire in another thread
553 >     * release in one thread enables acquire in another thread
554       */
555 <    public void testAcquireReleaseInDifferentThreads_fair() {
556 <        final Semaphore s = new Semaphore(0, true);
557 <        Thread t = new Thread(new Runnable() {
558 <                public void run() {
559 <                    try {
560 <                        s.acquire();
561 <                        s.acquire();
562 <                        s.acquire();
563 <                        s.acquire();
564 <                    } catch(InterruptedException ie){
565 <                        threadUnexpectedException();
566 <                    }
567 <                }
568 <            });
569 <        try {
570 <            t.start();
571 <            Thread.sleep(SHORT_DELAY_MS);
572 <            s.release();
573 <            s.release();
574 <            s.release();
575 <            s.release();
576 <            s.release();
577 <            s.release();
578 <            t.join();
579 <            assertEquals(2, s.availablePermits());
580 <        } catch( InterruptedException e){
581 <            unexpectedException();
555 >    public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
556 >    public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
557 >    public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
558 >    public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
559 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
560 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
561 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
562 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
563 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
564 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
565 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
566 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
567 >    public void testReleaseAcquireDifferentThreads(boolean fair,
568 >                                                   final AcquireMethod acquirer) {
569 >        final Semaphore s = new Semaphore(0, fair);
570 >        final int rounds = 4;
571 >        long startTime = System.nanoTime();
572 >        Thread t = newStartedThread(new CheckedRunnable() {
573 >            public void realRun() throws InterruptedException {
574 >                for (int i = 0; i < rounds; i++) {
575 >                    assertFalse(s.hasQueuedThreads());
576 >                    if (i % 2 == 0)
577 >                        acquirer.acquire(s);
578 >                    else
579 >                        acquirer.acquire(s, 3);
580 >                }}});
581 >
582 >        for (int i = 0; i < rounds; i++) {
583 >            while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
584 >                Thread.yield();
585 >            assertTrue(t.isAlive());
586 >            if (i % 2 == 0)
587 >                s.release();
588 >            else
589 >                s.release(3);
590          }
591 +        awaitTermination(t);
592 +        assertEquals(0, s.availablePermits());
593 +        assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
594      }
595  
596      /**
597 <     * release(n) in one thread enables acquire(n) in another thread
597 >     * fair locks are strictly FIFO
598       */
599 <    public void testAcquireReleaseNInDifferentThreads_fair() {
600 <        final Semaphore s = new Semaphore(0, true);
601 <        Thread t = new Thread(new Runnable() {
602 <                public void run() {
603 <                    try {
604 <                        s.acquire(2);
605 <                        s.acquire(2);
606 <                        s.release(4);
607 <                    } catch(InterruptedException ie){
608 <                        threadUnexpectedException();
609 <                    }
610 <                }
611 <            });
612 <        try {
613 <            t.start();
614 <            Thread.sleep(SHORT_DELAY_MS);
615 <            s.release(6);
616 <            s.acquire(2);
617 <            s.acquire(2);
618 <            s.release(2);
619 <            t.join();
620 <        } catch( InterruptedException e){
621 <            unexpectedException();
622 <        }
623 <    }
624 <
625 <
626 <
627 <    /**
628 <     * release in one thread enables timed acquire in another thread
629 <     */
630 <    public void testTimedAcquireReleaseInDifferentThreads_fair() {
631 <        final Semaphore s = new Semaphore(1, true);
632 <        Thread t = new Thread(new Runnable() {
633 <                public void run() {
609 <                    try {
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 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
615 <
616 <                    } catch(InterruptedException ie){
617 <                        threadUnexpectedException();
618 <                    }
619 <                }
620 <            });
621 <        t.start();
622 <        try {
623 <            s.release();
624 <            s.release();
625 <            s.release();
626 <            s.release();
627 <            s.release();
628 <            t.join();
629 <        } catch( InterruptedException e){
630 <            unexpectedException();
631 <        }
632 <    }
633 <
634 <    /**
635 <     * release(n) in one thread enables timed acquire(n) in another thread
636 <     */
637 <    public void testTimedAcquireReleaseNInDifferentThreads_fair() {
638 <        final Semaphore s = new Semaphore(2, true);
639 <        Thread t = new Thread(new Runnable() {
640 <                public void run() {
641 <                    try {
642 <                        threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
643 <                        s.release(2);
644 <                        threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
645 <                        s.release(2);
646 <                    } catch(InterruptedException ie){
647 <                        threadUnexpectedException();
648 <                    }
649 <                }
650 <            });
651 <        t.start();
652 <        try {
653 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
654 <            s.release(2);
655 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
656 <            s.release(2);
657 <            t.join();
658 <        } catch( InterruptedException e){
659 <            unexpectedException();
660 <        }
661 <    }
662 <
663 <    /**
664 <     * A waiting acquire blocks interruptibly
665 <     */
666 <    public void testAcquire_InterruptedException_fair() {
667 <        final Semaphore s = new Semaphore(0, true);
668 <        Thread t = new Thread(new Runnable() {
669 <                public void run() {
670 <                    try {
671 <                        s.acquire();
672 <                        threadShouldThrow();
673 <                    } catch(InterruptedException success){}
674 <                }
675 <            });
676 <        t.start();
677 <        try {
678 <            Thread.sleep(SHORT_DELAY_MS);
679 <            t.interrupt();
680 <            t.join();
681 <        } catch(InterruptedException e){
682 <            unexpectedException();
683 <        }
684 <    }
685 <
686 <    /**
687 <     * A waiting acquire(n) blocks interruptibly
688 <     */
689 <    public void testAcquireN_InterruptedException_fair() {
690 <        final Semaphore s = new Semaphore(2, true);
691 <        Thread t = new Thread(new Runnable() {
692 <                public void run() {
693 <                    try {
694 <                        s.acquire(3);
695 <                        threadShouldThrow();
696 <                    } catch(InterruptedException success){}
697 <                }
698 <            });
699 <        t.start();
700 <        try {
701 <            Thread.sleep(SHORT_DELAY_MS);
702 <            t.interrupt();
703 <            t.join();
704 <        } catch(InterruptedException e){
705 <            unexpectedException();
706 <        }
707 <    }
708 <    
709 <    /**
710 <     *  A waiting tryAcquire blocks interruptibly
711 <     */
712 <    public void testTryAcquire_InterruptedException_fair() {
713 <        final Semaphore s = new Semaphore(0, true);
714 <        Thread t = new Thread(new Runnable() {
715 <                public void run() {
716 <                    try {
717 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
718 <                        threadShouldThrow();
719 <                    } catch(InterruptedException success){
720 <                    }
721 <                }
722 <            });
723 <        t.start();
724 <        try {
725 <            Thread.sleep(SHORT_DELAY_MS);
726 <            t.interrupt();
727 <            t.join();
728 <        } catch(InterruptedException e){
729 <            unexpectedException();
730 <        }
731 <    }
732 <
733 <    /**
734 <     *  A waiting tryAcquire(n) blocks interruptibly
735 <     */
736 <    public void testTryAcquireN_InterruptedException_fair() {
737 <        final Semaphore s = new Semaphore(1, true);
738 <        Thread t = new Thread(new Runnable() {
739 <                public void run() {
740 <                    try {
741 <                        s.tryAcquire(4, MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
742 <                        threadShouldThrow();
743 <                    } catch(InterruptedException success){
744 <                    }
745 <                }
746 <            });
747 <        t.start();
748 <        try {
749 <            Thread.sleep(SHORT_DELAY_MS);
750 <            t.interrupt();
751 <            t.join();
752 <        } catch(InterruptedException e){
753 <            unexpectedException();
754 <        }
599 >    public void testFairLocksFifo() {
600 >        final PublicSemaphore s = new PublicSemaphore(1, true);
601 >        final CountDownLatch pleaseRelease = new CountDownLatch(1);
602 >        Thread t1 = newStartedThread(new CheckedRunnable() {
603 >            public void realRun() throws InterruptedException {
604 >                // Will block; permits are available, but not three
605 >                s.acquire(3);
606 >            }});
607 >
608 >        waitForQueuedThread(s, t1);
609 >
610 >        Thread t2 = newStartedThread(new CheckedRunnable() {
611 >            public void realRun() throws InterruptedException {
612 >                // Will fail, even though 1 permit is available
613 >                assertFalse(s.tryAcquire(0L, MILLISECONDS));
614 >                assertFalse(s.tryAcquire(1, 0L, MILLISECONDS));
615 >
616 >                // untimed tryAcquire will barge and succeed
617 >                assertTrue(s.tryAcquire());
618 >                s.release(2);
619 >                assertTrue(s.tryAcquire(2));
620 >                s.release();
621 >
622 >                pleaseRelease.countDown();
623 >                // Will queue up behind t1, even though 1 permit is available
624 >                s.acquire();
625 >            }});
626 >
627 >        await(pleaseRelease);
628 >        waitForQueuedThread(s, t2);
629 >        s.release(2);
630 >        awaitTermination(t1);
631 >        assertTrue(t2.isAlive());
632 >        s.release();
633 >        awaitTermination(t2);
634      }
635  
636      /**
637 <     * getQueueLength reports number of waiting threads
638 <     */
639 <    public void testGetQueueLength_fair() {
640 <        final Semaphore lock = new Semaphore(1, true);
641 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
642 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
643 <        try {
644 <            assertEquals(0, lock.getQueueLength());
645 <            lock.acquireUninterruptibly();
646 <            t1.start();
647 <            Thread.sleep(SHORT_DELAY_MS);
648 <            assertEquals(1, lock.getQueueLength());
649 <            t2.start();
771 <            Thread.sleep(SHORT_DELAY_MS);
772 <            assertEquals(2, lock.getQueueLength());
773 <            t1.interrupt();
774 <            Thread.sleep(SHORT_DELAY_MS);
775 <            assertEquals(1, lock.getQueueLength());
776 <            lock.release();
777 <            Thread.sleep(SHORT_DELAY_MS);
778 <            assertEquals(0, lock.getQueueLength());
779 <            t1.join();
780 <            t2.join();
781 <        } catch(Exception e){
782 <            unexpectedException();
783 <        }
784 <    }
785 <
786 <
787 <    /**
788 <     * a deserialized serialized semaphore has same number of permits
789 <     */
790 <    public void testSerialization_fair() {
791 <        Semaphore l = new Semaphore(3, true);
792 <
793 <        try {
794 <            l.acquire();
795 <            l.release();
796 <            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
797 <            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
798 <            out.writeObject(l);
799 <            out.close();
800 <
801 <            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
802 <            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
803 <            Semaphore r = (Semaphore) in.readObject();
804 <            assertEquals(3, r.availablePermits());
805 <            assertTrue(r.isFair());
806 <            r.acquire();
807 <            r.release();
808 <        } catch(Exception e){
809 <            unexpectedException();
810 <        }
637 >     * toString indicates current number of permits
638 >     */
639 >    public void testToString()      { testToString(false); }
640 >    public void testToString_fair() { testToString(true); }
641 >    public void testToString(boolean fair) {
642 >        PublicSemaphore s = new PublicSemaphore(0, fair);
643 >        assertTrue(s.toString().contains("Permits = 0"));
644 >        s.release();
645 >        assertTrue(s.toString().contains("Permits = 1"));
646 >        s.release(2);
647 >        assertTrue(s.toString().contains("Permits = 3"));
648 >        s.reducePermits(5);
649 >        assertTrue(s.toString().contains("Permits = -2"));
650      }
651  
813
652   }

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