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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 1.44 by jsr166, Mon Aug 12 06:21:11 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 > import java.util.concurrent.ThreadLocalRandom;
15 >
16 > import junit.framework.Test;
17 > import junit.framework.TestSuite;
18  
19   public class SemaphoreTest extends JSR166TestCase {
20      public static void main(String[] args) {
21 <        junit.textui.TestRunner.run (suite());  
21 >        main(suite(), args);
22      }
23      public static Test suite() {
24 <        return new TestSuite(SemaphoreTest.class);
24 >        return new TestSuite(SemaphoreTest.class);
25      }
26  
27      /**
28       * Subclass to expose protected methods
29       */
30      static class PublicSemaphore extends Semaphore {
31 <        PublicSemaphore(int p, boolean f) { super(p, f); }
32 <        public Collection<Thread> getQueuedThreads() {
33 <            return super.getQueuedThreads();
31 >        PublicSemaphore(int permits) { super(permits); }
32 >        PublicSemaphore(int permits, boolean fair) { super(permits, fair); }
33 >        public Collection<Thread> getQueuedThreads() {
34 >            return super.getQueuedThreads();
35          }
36 <        public void reducePermits(int p) {
37 <            super.reducePermits(p);
36 >        public boolean hasQueuedThread(Thread t) {
37 >            return super.getQueuedThreads().contains(t);
38 >        }
39 >        public void reducePermits(int reduction) {
40 >            super.reducePermits(reduction);
41          }
42      }
43  
44      /**
45       * A runnable calling acquire
46       */
47 <    class InterruptibleLockRunnable implements Runnable {
47 >    class InterruptibleLockRunnable extends CheckedRunnable {
48          final Semaphore lock;
49 <        InterruptibleLockRunnable(Semaphore l) { lock = l; }
50 <        public void run() {
49 >        InterruptibleLockRunnable(Semaphore s) { lock = s; }
50 >        public void realRun() {
51              try {
52                  lock.acquire();
53 <            } catch(InterruptedException success){}
53 >            }
54 >            catch (InterruptedException ignored) {}
55          }
56      }
57  
47
58      /**
59 <     * A runnable calling acquire that expects to be
50 <     * interrupted
59 >     * A runnable calling acquire that expects to be interrupted
60       */
61 <    class InterruptedLockRunnable implements Runnable {
61 >    class InterruptedLockRunnable extends CheckedInterruptedRunnable {
62          final Semaphore lock;
63 <        InterruptedLockRunnable(Semaphore l) { lock = l; }
64 <        public void run() {
65 <            try {
66 <                lock.acquire();
67 <                threadShouldThrow();
68 <            } catch(InterruptedException success){}
63 >        InterruptedLockRunnable(Semaphore s) { lock = s; }
64 >        public void realRun() throws InterruptedException {
65 >            lock.acquire();
66 >        }
67 >    }
68 >
69 >    /**
70 >     * Spin-waits until s.hasQueuedThread(t) becomes true.
71 >     */
72 >    void waitForQueuedThread(PublicSemaphore s, Thread t) {
73 >        long startTime = System.nanoTime();
74 >        while (!s.hasQueuedThread(t)) {
75 >            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
76 >                throw new AssertionError("timed out");
77 >            Thread.yield();
78 >        }
79 >        assertTrue(s.hasQueuedThreads());
80 >        assertTrue(t.isAlive());
81 >    }
82 >
83 >    /**
84 >     * Spin-waits until s.hasQueuedThreads() becomes true.
85 >     */
86 >    void waitForQueuedThreads(Semaphore s) {
87 >        long startTime = System.nanoTime();
88 >        while (!s.hasQueuedThreads()) {
89 >            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
90 >                throw new AssertionError("timed out");
91 >            Thread.yield();
92 >        }
93 >    }
94 >
95 >    enum AcquireMethod {
96 >        acquire() {
97 >            void acquire(Semaphore s) throws InterruptedException {
98 >                s.acquire();
99 >            }
100 >        },
101 >        acquireN() {
102 >            void acquire(Semaphore s, int permits) throws InterruptedException {
103 >                s.acquire(permits);
104 >            }
105 >        },
106 >        acquireUninterruptibly() {
107 >            void acquire(Semaphore s) {
108 >                s.acquireUninterruptibly();
109 >            }
110 >        },
111 >        acquireUninterruptiblyN() {
112 >            void acquire(Semaphore s, int permits) {
113 >                s.acquireUninterruptibly(permits);
114 >            }
115 >        },
116 >        tryAcquire() {
117 >            void acquire(Semaphore s) {
118 >                assertTrue(s.tryAcquire());
119 >            }
120 >        },
121 >        tryAcquireN() {
122 >            void acquire(Semaphore s, int permits) {
123 >                assertTrue(s.tryAcquire(permits));
124 >            }
125 >        },
126 >        tryAcquireTimed() {
127 >            void acquire(Semaphore s) throws InterruptedException {
128 >                assertTrue(s.tryAcquire(2 * LONG_DELAY_MS, MILLISECONDS));
129 >            }
130 >            Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
131 >        },
132 >        tryAcquireTimedN {
133 >            void acquire(Semaphore s, int permits) throws InterruptedException {
134 >                assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS));
135 >            }
136 >            Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
137 >        };
138 >
139 >        // Intentionally meta-circular
140 >
141 >        /** Acquires 1 permit. */
142 >        void acquire(Semaphore s) throws InterruptedException {
143 >            acquire(s, 1);
144 >        }
145 >        /** Acquires the given number of permits. */
146 >        void acquire(Semaphore s, int permits) throws InterruptedException {
147 >            for (int i = 0; i < permits; i++)
148 >                acquire(s);
149          }
150 +        Thread.State parkedState() { return Thread.State.WAITING; }
151      }
152  
153      /**
154       * Zero, negative, and positive initial values are allowed in constructor
155       */
156 <    public void testConstructor() {
157 <        Semaphore s0 = new Semaphore(0, false);
158 <        assertEquals(0, s0.availablePermits());
159 <        assertFalse(s0.isFair());
160 <        Semaphore s1 = new Semaphore(-1, false);
161 <        assertEquals(-1, s1.availablePermits());
162 <        Semaphore s2 = new Semaphore(-1, false);
163 <        assertEquals(-1, s2.availablePermits());
156 >    public void testConstructor()      { testConstructor(false); }
157 >    public void testConstructor_fair() { testConstructor(true); }
158 >    public void testConstructor(boolean fair) {
159 >        for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
160 >            Semaphore s = new Semaphore(permits, fair);
161 >            assertEquals(permits, s.availablePermits());
162 >            assertEquals(fair, s.isFair());
163 >        }
164 >    }
165 >
166 >    /**
167 >     * Constructor without fairness argument behaves as nonfair
168 >     */
169 >    public void testConstructorDefaultsToNonFair() {
170 >        for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
171 >            Semaphore s = new Semaphore(permits);
172 >            assertEquals(permits, s.availablePermits());
173 >            assertFalse(s.isFair());
174 >        }
175      }
176  
177      /**
178 <     * tryAcquire succeeds when sufficent permits, else fails
178 >     * tryAcquire succeeds when sufficient permits, else fails
179       */
180 <    public void testTryAcquireInSameThread() {
181 <        Semaphore s = new Semaphore(2, false);
180 >    public void testTryAcquireInSameThread()      { testTryAcquireInSameThread(false); }
181 >    public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); }
182 >    public void testTryAcquireInSameThread(boolean fair) {
183 >        Semaphore s = new Semaphore(2, fair);
184          assertEquals(2, s.availablePermits());
185          assertTrue(s.tryAcquire());
186          assertTrue(s.tryAcquire());
187          assertEquals(0, s.availablePermits());
188          assertFalse(s.tryAcquire());
189 +        assertFalse(s.tryAcquire());
190 +        assertEquals(0, s.availablePermits());
191      }
192  
193      /**
194 <     * Acquire and release of semaphore succeed if initially available
194 >     * timed tryAcquire times out
195       */
196 <    public void testAcquireReleaseInSameThread() {
197 <        Semaphore s = new Semaphore(1, false);
198 <        try {
199 <            s.acquire();
200 <            s.release();
201 <            s.acquire();
202 <            s.release();
203 <            s.acquire();
204 <            s.release();
205 <            s.acquire();
206 <            s.release();
207 <            s.acquire();
208 <            s.release();
209 <            assertEquals(1, s.availablePermits());
210 <        } catch( InterruptedException e){
211 <            unexpectedException();
196 >    public void testTryAcquire_timeout() throws InterruptedException {
197 >        final boolean fair = randomBoolean();
198 >        final Semaphore s = new Semaphore(0, fair);
199 >        final long startTime = System.nanoTime();
200 >        assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS));
201 >        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
202 >    }
203 >
204 >    /**
205 >     * timed tryAcquire(N) times out
206 >     */
207 >    public void testTryAcquireN_timeout() throws InterruptedException {
208 >        final boolean fair = randomBoolean();
209 >        final Semaphore s = new Semaphore(2, fair);
210 >        final long startTime = System.nanoTime();
211 >        assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS));
212 >        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
213 >    }
214 >
215 >    /**
216 >     * acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
217 >     * are interruptible
218 >     */
219 >    public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
220 >    public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
221 >    public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
222 >    public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
223 >    public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
224 >    public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
225 >    public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
226 >    public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
227 >    public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
228 >        final PublicSemaphore s = new PublicSemaphore(0, fair);
229 >        final java.util.concurrent.CyclicBarrier pleaseInterrupt
230 >            = new java.util.concurrent.CyclicBarrier(2);
231 >        Thread t = newStartedThread(new CheckedRunnable() {
232 >            public void realRun() {
233 >                // Interrupt before acquire
234 >                Thread.currentThread().interrupt();
235 >                try {
236 >                    acquirer.acquire(s);
237 >                    shouldThrow();
238 >                } catch (InterruptedException success) {}
239 >                assertFalse(Thread.interrupted());
240 >
241 >                // Interrupt before acquire(N)
242 >                Thread.currentThread().interrupt();
243 >                try {
244 >                    acquirer.acquire(s, 3);
245 >                    shouldThrow();
246 >                } catch (InterruptedException success) {}
247 >                assertFalse(Thread.interrupted());
248 >
249 >                // Interrupt during acquire
250 >                await(pleaseInterrupt);
251 >                try {
252 >                    acquirer.acquire(s);
253 >                    shouldThrow();
254 >                } catch (InterruptedException success) {}
255 >                assertFalse(Thread.interrupted());
256 >
257 >                // Interrupt during acquire(N)
258 >                await(pleaseInterrupt);
259 >                try {
260 >                    acquirer.acquire(s, 3);
261 >                    shouldThrow();
262 >                } catch (InterruptedException success) {}
263 >                assertFalse(Thread.interrupted());
264 >            }});
265 >
266 >        for (int n = 2; n-->0; ) {
267 >            await(pleaseInterrupt);
268 >            assertThreadBlocks(t, acquirer.parkedState());
269 >            t.interrupt();
270          }
108    }
271  
272 <    /**
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 <        }
272 >        awaitTermination(t);
273      }
274  
275      /**
276 <     * Timed Acquire and release of semaphore succeed if
277 <     * initially available
276 >     * acquireUninterruptibly(), acquireUninterruptibly(N) are
277 >     * uninterruptible
278       */
279 <    public void testTimedAcquireReleaseInSameThread() {
280 <        Semaphore s = new Semaphore(1, false);
281 <        try {
282 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
283 <            s.release();
284 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
285 <            s.release();
286 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
287 <            s.release();
288 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
289 <            s.release();
290 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
291 <            s.release();
292 <            assertEquals(1, s.availablePermits());
293 <        } catch( InterruptedException e){
294 <            unexpectedException();
295 <        }
279 >    public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
280 >    public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
281 >    public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
282 >    public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
283 >    public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
284 >        final PublicSemaphore s = new PublicSemaphore(0, fair);
285 >        final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
286 >
287 >        Thread t1 = newStartedThread(new CheckedRunnable() {
288 >            public void realRun() throws InterruptedException {
289 >                // Interrupt before acquire
290 >                pleaseInterrupt.release();
291 >                Thread.currentThread().interrupt();
292 >                acquirer.acquire(s);
293 >                assertTrue(Thread.interrupted());
294 >            }});
295 >
296 >        Thread t2 = newStartedThread(new CheckedRunnable() {
297 >            public void realRun() throws InterruptedException {
298 >                // Interrupt during acquire
299 >                pleaseInterrupt.release();
300 >                acquirer.acquire(s);
301 >                assertTrue(Thread.interrupted());
302 >            }});
303 >
304 >        await(pleaseInterrupt);
305 >        waitForQueuedThread(s, t1);
306 >        waitForQueuedThread(s, t2);
307 >        t2.interrupt();
308 >
309 >        assertThreadBlocks(t1, Thread.State.WAITING);
310 >        assertThreadBlocks(t2, Thread.State.WAITING);
311 >
312 >        s.release(2);
313 >
314 >        awaitTermination(t1);
315 >        awaitTermination(t2);
316 >    }
317 >
318 >    /**
319 >     * hasQueuedThreads reports whether there are waiting threads
320 >     */
321 >    public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
322 >    public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
323 >    public void testHasQueuedThreads(boolean fair) {
324 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
325 >        assertFalse(lock.hasQueuedThreads());
326 >        lock.acquireUninterruptibly();
327 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
328 >        waitForQueuedThread(lock, t1);
329 >        assertTrue(lock.hasQueuedThreads());
330 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
331 >        waitForQueuedThread(lock, t2);
332 >        assertTrue(lock.hasQueuedThreads());
333 >        t1.interrupt();
334 >        awaitTermination(t1);
335 >        assertTrue(lock.hasQueuedThreads());
336 >        lock.release();
337 >        awaitTermination(t2);
338 >        assertFalse(lock.hasQueuedThreads());
339      }
340  
341      /**
342 <     * 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
342 >     * getQueueLength reports number of waiting threads
343       */
344 <    public void testUninterruptibleAcquireReleaseInDifferentThreads() {
345 <        final Semaphore s = new Semaphore(0, false);
346 <        Thread t = new Thread(new Runnable() {
347 <                public void run() {
348 <                    s.acquireUninterruptibly();
349 <                    s.release();
350 <                    s.release();
351 <                    s.acquireUninterruptibly();
352 <                }
353 <            });
354 <        try {
355 <            t.start();
356 <            Thread.sleep(SHORT_DELAY_MS);
357 <            s.release();
358 <            s.release();
359 <            s.acquireUninterruptibly();
360 <            s.acquireUninterruptibly();
361 <            s.release();
207 <            t.join();
208 <        } catch( InterruptedException e){
209 <            unexpectedException();
210 <        }
344 >    public void testGetQueueLength()      { testGetQueueLength(false); }
345 >    public void testGetQueueLength_fair() { testGetQueueLength(true); }
346 >    public void testGetQueueLength(boolean fair) {
347 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
348 >        assertEquals(0, lock.getQueueLength());
349 >        lock.acquireUninterruptibly();
350 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
351 >        waitForQueuedThread(lock, t1);
352 >        assertEquals(1, lock.getQueueLength());
353 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
354 >        waitForQueuedThread(lock, t2);
355 >        assertEquals(2, lock.getQueueLength());
356 >        t1.interrupt();
357 >        awaitTermination(t1);
358 >        assertEquals(1, lock.getQueueLength());
359 >        lock.release();
360 >        awaitTermination(t2);
361 >        assertEquals(0, lock.getQueueLength());
362      }
363  
213
364      /**
365 <     *  A release in one thread enables a timed acquire in another thread
365 >     * getQueuedThreads includes waiting threads
366       */
367 <    public void testTimedAcquireReleaseInDifferentThreads() {
368 <        final Semaphore s = new Semaphore(1, false);
369 <        Thread t = new Thread(new Runnable() {
370 <                public void run() {
371 <                    try {
372 <                        s.release();
373 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
374 <                        s.release();
375 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
376 <
377 <                    } catch(InterruptedException ie){
378 <                        threadUnexpectedException();
379 <                    }
380 <                }
381 <            });
382 <        try {
383 <            t.start();
384 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
385 <            s.release();
386 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
387 <            s.release();
238 <            s.release();
239 <            t.join();
240 <        } catch( InterruptedException e){
241 <            unexpectedException();
242 <        }
367 >    public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
368 >    public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
369 >    public void testGetQueuedThreads(boolean fair) {
370 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
371 >        assertTrue(lock.getQueuedThreads().isEmpty());
372 >        lock.acquireUninterruptibly();
373 >        assertTrue(lock.getQueuedThreads().isEmpty());
374 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
375 >        waitForQueuedThread(lock, t1);
376 >        assertTrue(lock.getQueuedThreads().contains(t1));
377 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
378 >        waitForQueuedThread(lock, t2);
379 >        assertTrue(lock.getQueuedThreads().contains(t1));
380 >        assertTrue(lock.getQueuedThreads().contains(t2));
381 >        t1.interrupt();
382 >        awaitTermination(t1);
383 >        assertFalse(lock.getQueuedThreads().contains(t1));
384 >        assertTrue(lock.getQueuedThreads().contains(t2));
385 >        lock.release();
386 >        awaitTermination(t2);
387 >        assertTrue(lock.getQueuedThreads().isEmpty());
388      }
389  
390      /**
391 <     * A waiting acquire blocks interruptibly
392 <     */
393 <    public void testAcquire_InterruptedException() {
394 <        final Semaphore s = new Semaphore(0, false);
395 <        Thread t = new Thread(new Runnable() {
396 <                public void run() {
397 <                    try {
398 <                        s.acquire();
399 <                        threadShouldThrow();
400 <                    } catch(InterruptedException success){}
401 <                }
402 <            });
403 <        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 <        }
391 >     * drainPermits reports and removes given number of permits
392 >     */
393 >    public void testDrainPermits()      { testDrainPermits(false); }
394 >    public void testDrainPermits_fair() { testDrainPermits(true); }
395 >    public void testDrainPermits(boolean fair) {
396 >        Semaphore s = new Semaphore(0, fair);
397 >        assertEquals(0, s.availablePermits());
398 >        assertEquals(0, s.drainPermits());
399 >        s.release(10);
400 >        assertEquals(10, s.availablePermits());
401 >        assertEquals(10, s.drainPermits());
402 >        assertEquals(0, s.availablePermits());
403 >        assertEquals(0, s.drainPermits());
404      }
405  
406      /**
407 <     * getQueueLength reports number of waiting threads
407 >     * release(-N) throws IllegalArgumentException
408       */
409 <    public void testGetQueueLength() {
410 <        final Semaphore lock = new Semaphore(1, false);
411 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
412 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
409 >    public void testReleaseIAE()      { testReleaseIAE(false); }
410 >    public void testReleaseIAE_fair() { testReleaseIAE(true); }
411 >    public void testReleaseIAE(boolean fair) {
412 >        Semaphore s = new Semaphore(10, fair);
413          try {
414 <            assertEquals(0, lock.getQueueLength());
415 <            lock.acquireUninterruptibly();
416 <            t1.start();
417 <            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 <    }
414 >            s.release(-1);
415 >            shouldThrow();
416 >        } catch (IllegalArgumentException success) {}
417 >    }
418  
419      /**
420 <     * getQueuedThreads includes waiting threads
420 >     * reducePermits(-N) throws IllegalArgumentException
421       */
422 <    public void testGetQueuedThreads() {
423 <        final PublicSemaphore lock = new PublicSemaphore(1, false);
424 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
425 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
422 >    public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
423 >    public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
424 >    public void testReducePermitsIAE(boolean fair) {
425 >        PublicSemaphore s = new PublicSemaphore(10, fair);
426          try {
427 <            assertTrue(lock.getQueuedThreads().isEmpty());
428 <            lock.acquireUninterruptibly();
429 <            assertTrue(lock.getQueuedThreads().isEmpty());
430 <            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 <
427 >            s.reducePermits(-1);
428 >            shouldThrow();
429 >        } catch (IllegalArgumentException success) {}
430 >    }
431  
432      /**
433       * reducePermits reduces number of permits
434       */
435 <    public void testReducePermits() {
436 <        PublicSemaphore s = new PublicSemaphore(10, false);
435 >    public void testReducePermits()      { testReducePermits(false); }
436 >    public void testReducePermits_fair() { testReducePermits(true); }
437 >    public void testReducePermits(boolean fair) {
438 >        PublicSemaphore s = new PublicSemaphore(10, fair);
439 >        assertEquals(10, s.availablePermits());
440 >        s.reducePermits(0);
441          assertEquals(10, s.availablePermits());
442          s.reducePermits(1);
443          assertEquals(9, s.availablePermits());
444          s.reducePermits(10);
445          assertEquals(-1, s.availablePermits());
446 +        s.reducePermits(10);
447 +        assertEquals(-11, s.availablePermits());
448 +        s.reducePermits(0);
449 +        assertEquals(-11, s.availablePermits());
450      }
451  
452      /**
453 <     * a deserialized serialized semaphore has same number of permits
454 <     */
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
453 >     * a reserialized semaphore has same number of permits and
454 >     * fairness, but no queued threads
455       */
456 <    public void testAcquireReleaseInSameThread_fair() {
457 <        Semaphore s = new Semaphore(1, true);
456 >    public void testSerialization()      { testSerialization(false); }
457 >    public void testSerialization_fair() { testSerialization(true); }
458 >    public void testSerialization(boolean fair) {
459          try {
460 +            Semaphore s = new Semaphore(3, fair);
461              s.acquire();
435            s.release();
462              s.acquire();
463              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    }
464  
465 <    /**
466 <     * Acquire(n) and release(n) of semaphore succeed if initially available
467 <     */
468 <    public void testAcquireReleaseNInSameThread_fair() {
469 <        Semaphore s = new Semaphore(1, true);
470 <        try {
471 <            s.release(1);
472 <            s.acquire(1);
473 <            s.release(2);
474 <            s.acquire(2);
475 <            s.release(3);
476 <            s.acquire(3);
477 <            s.release(4);
478 <            s.acquire(4);
479 <            s.release(5);
480 <            s.acquire(5);
481 <            assertEquals(1, s.availablePermits());
482 <        } catch( InterruptedException e){
483 <            unexpectedException();
465 >            Semaphore clone = serialClone(s);
466 >            assertEquals(fair, s.isFair());
467 >            assertEquals(fair, clone.isFair());
468 >            assertEquals(2, s.availablePermits());
469 >            assertEquals(2, clone.availablePermits());
470 >            clone.acquire();
471 >            clone.acquire();
472 >            clone.release();
473 >            assertEquals(2, s.availablePermits());
474 >            assertEquals(1, clone.availablePermits());
475 >            assertFalse(s.hasQueuedThreads());
476 >            assertFalse(clone.hasQueuedThreads());
477 >        } catch (InterruptedException e) { threadUnexpectedException(e); }
478 >
479 >        {
480 >            PublicSemaphore s = new PublicSemaphore(0, fair);
481 >            Thread t = newStartedThread(new InterruptibleLockRunnable(s));
482 >            // waitForQueuedThreads(s); // suffers from "flicker", so ...
483 >            waitForQueuedThread(s, t);  // ... we use this instead
484 >            PublicSemaphore clone = serialClone(s);
485 >            assertEquals(fair, s.isFair());
486 >            assertEquals(fair, clone.isFair());
487 >            assertEquals(0, s.availablePermits());
488 >            assertEquals(0, clone.availablePermits());
489 >            assertTrue(s.hasQueuedThreads());
490 >            assertFalse(clone.hasQueuedThreads());
491 >            s.release();
492 >            awaitTermination(t);
493 >            assertFalse(s.hasQueuedThreads());
494 >            assertFalse(clone.hasQueuedThreads());
495          }
496      }
497  
498      /**
499 <     * Acquire(n) and release(n) of semaphore succeed if initially available
500 <     */
501 <    public void testAcquireUninterruptiblyReleaseNInSameThread_fair() {
502 <        Semaphore s = new Semaphore(1, true);
503 <        try {
504 <            s.release(1);
505 <            s.acquireUninterruptibly(1);
506 <            s.release(2);
507 <            s.acquireUninterruptibly(2);
508 <            s.release(3);
509 <            s.acquireUninterruptibly(3);
510 <            s.release(4);
511 <            s.acquireUninterruptibly(4);
512 <            s.release(5);
487 <            s.acquireUninterruptibly(5);
488 <            assertEquals(1, s.availablePermits());
489 <        } finally {
490 <        }
499 >     * tryAcquire(n) succeeds when sufficient permits, else fails
500 >     */
501 >    public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
502 >    public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
503 >    public void testTryAcquireNInSameThread(boolean fair) {
504 >        Semaphore s = new Semaphore(2, fair);
505 >        assertEquals(2, s.availablePermits());
506 >        assertFalse(s.tryAcquire(3));
507 >        assertEquals(2, s.availablePermits());
508 >        assertTrue(s.tryAcquire(2));
509 >        assertEquals(0, s.availablePermits());
510 >        assertFalse(s.tryAcquire(1));
511 >        assertFalse(s.tryAcquire(2));
512 >        assertEquals(0, s.availablePermits());
513      }
514  
515      /**
516 <     * release(n) in one thread enables timed acquire(n) in another thread
516 >     * acquire succeeds if permits available
517       */
518 <    public void testTimedAcquireReleaseNInSameThread_fair() {
519 <        Semaphore s = new Semaphore(1, true);
520 <        try {
521 <            s.release(1);
522 <            assertTrue(s.tryAcquire(1, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
523 <            s.release(2);
524 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
525 <            s.release(3);
526 <            assertTrue(s.tryAcquire(3, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
527 <            s.release(4);
528 <            assertTrue(s.tryAcquire(4, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
529 <            s.release(5);
530 <            assertTrue(s.tryAcquire(5, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
518 >    public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
519 >    public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
520 >    public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
521 >    public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
522 >    public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
523 >    public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
524 >    public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
525 >    public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
526 >    public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
527 >    public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
528 >    public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
529 >    public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
530 >    public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
531 >    public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
532 >    public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
533 >    public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
534 >    public void testReleaseAcquireSameThread(boolean fair,
535 >                                             final AcquireMethod acquirer) {
536 >        Semaphore s = new Semaphore(1, fair);
537 >        for (int i = 1; i < 6; i++) {
538 >            s.release(i);
539 >            assertEquals(1 + i, s.availablePermits());
540 >            try {
541 >                acquirer.acquire(s, i);
542 >            } catch (InterruptedException e) { threadUnexpectedException(e); }
543              assertEquals(1, s.availablePermits());
510        } catch( InterruptedException e){
511            unexpectedException();
544          }
545      }
546  
547      /**
548 <     * release in one thread enables timed acquire in another thread
548 >     * release in one thread enables acquire in another thread
549       */
550 <    public void testTimedAcquireReleaseInSameThread_fair() {
551 <        Semaphore s = new Semaphore(1, true);
552 <        try {
553 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
554 <            s.release();
555 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
556 <            s.release();
557 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
558 <            s.release();
559 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
560 <            s.release();
561 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
562 <            s.release();
563 <            assertEquals(1, s.availablePermits());
564 <        } catch( InterruptedException e){
565 <            unexpectedException();
566 <        }
567 <    }
568 <
569 <    /**
570 <     * A release in one thread enables an acquire in another thread
571 <     */
572 <    public void testAcquireReleaseInDifferentThreads_fair() {
573 <        final Semaphore s = new Semaphore(0, true);
574 <        Thread t = new Thread(new Runnable() {
575 <                public void run() {
576 <                    try {
577 <                        s.acquire();
578 <                        s.acquire();
579 <                        s.acquire();
580 <                        s.acquire();
581 <                    } catch(InterruptedException ie){
582 <                        threadUnexpectedException();
583 <                    }
584 <                }
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();
550 >    public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
551 >    public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
552 >    public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
553 >    public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
554 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
555 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
556 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
557 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
558 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
559 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
560 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
561 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
562 >    public void testReleaseAcquireDifferentThreads(boolean fair,
563 >                                                   final AcquireMethod acquirer) {
564 >        final Semaphore s = new Semaphore(0, fair);
565 >        final int rounds = 4;
566 >        long startTime = System.nanoTime();
567 >        Thread t = newStartedThread(new CheckedRunnable() {
568 >            public void realRun() throws InterruptedException {
569 >                for (int i = 0; i < rounds; i++) {
570 >                    assertFalse(s.hasQueuedThreads());
571 >                    if (i % 2 == 0)
572 >                        acquirer.acquire(s);
573 >                    else
574 >                        acquirer.acquire(s, 3);
575 >                }}});
576 >
577 >        for (int i = 0; i < rounds; i++) {
578 >            while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
579 >                Thread.yield();
580 >            assertTrue(t.isAlive());
581 >            if (i % 2 == 0)
582 >                s.release();
583 >            else
584 >                s.release(3);
585          }
586 +        awaitTermination(t);
587 +        assertEquals(0, s.availablePermits());
588 +        assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
589      }
590  
591      /**
592 <     * release(n) in one thread enables acquire(n) in another thread
592 >     * fair locks are strictly FIFO
593       */
594 <    public void testAcquireReleaseNInDifferentThreads_fair() {
595 <        final Semaphore s = new Semaphore(0, true);
596 <        Thread t = new Thread(new Runnable() {
597 <                public void run() {
598 <                    try {
599 <                        s.acquire(2);
600 <                        s.acquire(2);
601 <                        s.release(4);
602 <                    } catch(InterruptedException ie){
603 <                        threadUnexpectedException();
604 <                    }
605 <                }
606 <            });
607 <        try {
608 <            t.start();
609 <            Thread.sleep(SHORT_DELAY_MS);
610 <            s.release(6);
611 <            s.acquire(2);
612 <            s.acquire(2);
613 <            s.release(2);
614 <            t.join();
615 <        } catch( InterruptedException e){
616 <            unexpectedException();
617 <        }
618 <    }
619 <
620 <
621 <
622 <    /**
623 <     * release in one thread enables timed acquire in another thread
624 <     */
625 <    public void testTimedAcquireReleaseInDifferentThreads_fair() {
626 <        final Semaphore s = new Semaphore(1, true);
627 <        Thread t = new Thread(new Runnable() {
628 <                public void run() {
629 <                    try {
630 <                        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 <        }
594 >    public void testFairLocksFifo() {
595 >        final PublicSemaphore s = new PublicSemaphore(1, true);
596 >        final CountDownLatch pleaseRelease = new CountDownLatch(1);
597 >        Thread t1 = newStartedThread(new CheckedRunnable() {
598 >            public void realRun() throws InterruptedException {
599 >                // Will block; permits are available, but not three
600 >                s.acquire(3);
601 >            }});
602 >
603 >        waitForQueuedThread(s, t1);
604 >
605 >        Thread t2 = newStartedThread(new CheckedRunnable() {
606 >            public void realRun() throws InterruptedException {
607 >                // Will fail, even though 1 permit is available
608 >                assertFalse(
609 >                    s.tryAcquire(randomExpiredTimeout(), randomTimeUnit()));
610 >                assertFalse(
611 >                    s.tryAcquire(1, randomExpiredTimeout(), randomTimeUnit()));
612 >
613 >                // untimed tryAcquire will barge and succeed
614 >                assertTrue(s.tryAcquire());
615 >                s.release(2);
616 >                assertTrue(s.tryAcquire(2));
617 >                s.release();
618 >
619 >                pleaseRelease.countDown();
620 >                // Will queue up behind t1, even though 1 permit is available
621 >                s.acquire();
622 >            }});
623 >
624 >        await(pleaseRelease);
625 >        waitForQueuedThread(s, t2);
626 >        s.release(2);
627 >        awaitTermination(t1);
628 >        assertTrue(t2.isAlive());
629 >        s.release();
630 >        awaitTermination(t2);
631      }
632  
633      /**
634 <     * getQueueLength reports number of waiting threads
635 <     */
636 <    public void testGetQueueLength_fair() {
637 <        final Semaphore lock = new Semaphore(1, true);
638 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
639 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
640 <        try {
641 <            assertEquals(0, lock.getQueueLength());
642 <            lock.acquireUninterruptibly();
643 <            t1.start();
644 <            Thread.sleep(SHORT_DELAY_MS);
645 <            assertEquals(1, lock.getQueueLength());
646 <            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 <        }
634 >     * toString indicates current number of permits
635 >     */
636 >    public void testToString()      { testToString(false); }
637 >    public void testToString_fair() { testToString(true); }
638 >    public void testToString(boolean fair) {
639 >        PublicSemaphore s = new PublicSemaphore(0, fair);
640 >        assertTrue(s.toString().contains("Permits = 0"));
641 >        s.release();
642 >        assertTrue(s.toString().contains("Permits = 1"));
643 >        s.release(2);
644 >        assertTrue(s.toString().contains("Permits = 3"));
645 >        s.reducePermits(5);
646 >        assertTrue(s.toString().contains("Permits = -2"));
647      }
648  
812
649   }

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