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Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.12 by dl, Sun Jan 4 22:58:03 2004 UTC vs.
Revision 1.44 by jsr166, Mon Aug 12 06:21:11 2019 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.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  
48
58      /**
59 <     * A runnable calling acquire that expects to be
51 <     * 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 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          }
109    }
271  
272 <    /**
112 <     * Uninterruptible acquire and release of semaphore succeed if
113 <     * initially available
114 <     */
115 <    public void testAcquireUninterruptiblyReleaseInSameThread() {
116 <        Semaphore s = new Semaphore(1, false);
117 <        try {
118 <            s.acquireUninterruptibly();
119 <            s.release();
120 <            s.acquireUninterruptibly();
121 <            s.release();
122 <            s.acquireUninterruptibly();
123 <            s.release();
124 <            s.acquireUninterruptibly();
125 <            s.release();
126 <            s.acquireUninterruptibly();
127 <            s.release();
128 <            assertEquals(1, s.availablePermits());
129 <        } finally {
130 <        }
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 <        }
296 <    }
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 <    /**
310 <     * A release in one thread enables an acquire in another thread
158 <     */
159 <    public void testAcquireReleaseInDifferentThreads() {
160 <        final Semaphore s = new Semaphore(0, false);
161 <        Thread t = new Thread(new Runnable() {
162 <                public void run() {
163 <                    try {
164 <                        s.acquire();
165 <                        s.release();
166 <                        s.release();
167 <                        s.acquire();
168 <                    } catch(InterruptedException ie){
169 <                        threadUnexpectedException();
170 <                    }
171 <                }
172 <            });
173 <        try {
174 <            t.start();
175 <            Thread.sleep(SHORT_DELAY_MS);
176 <            s.release();
177 <            s.release();
178 <            s.acquire();
179 <            s.acquire();
180 <            s.release();
181 <            t.join();
182 <        } catch( InterruptedException e){
183 <            unexpectedException();
184 <        }
185 <    }
186 <
187 <    /**
188 <     * A release in one thread enables an uninterruptible acquire in another thread
189 <     */
190 <    public void testUninterruptibleAcquireReleaseInDifferentThreads() {
191 <        final Semaphore s = new Semaphore(0, false);
192 <        Thread t = new Thread(new Runnable() {
193 <                public void run() {
194 <                    s.acquireUninterruptibly();
195 <                    s.release();
196 <                    s.release();
197 <                    s.acquireUninterruptibly();
198 <                }
199 <            });
200 <        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 <        }
212 <    }
309 >        assertThreadBlocks(t1, Thread.State.WAITING);
310 >        assertThreadBlocks(t2, Thread.State.WAITING);
311  
312 +        s.release(2);
313  
314 <    /**
315 <     *  A release in one thread enables a timed acquire in another thread
217 <     */
218 <    public void testTimedAcquireReleaseInDifferentThreads() {
219 <        final Semaphore s = new Semaphore(1, false);
220 <        Thread t = new Thread(new Runnable() {
221 <                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 <            });
233 <        try {
234 <            t.start();
235 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
236 <            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 <        }
314 >        awaitTermination(t1);
315 >        awaitTermination(t2);
316      }
317  
318      /**
319       * hasQueuedThreads reports whether there are waiting threads
320       */
321 <    public void testHasQueuedThreads() {
322 <        final Semaphore lock = new Semaphore(1, false);
323 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
324 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
325 <        try {
326 <            assertFalse(lock.hasQueuedThreads());
327 <            lock.acquireUninterruptibly();
328 <            t1.start();
329 <            Thread.sleep(SHORT_DELAY_MS);
330 <            assertTrue(lock.hasQueuedThreads());
331 <            t2.start();
332 <            Thread.sleep(SHORT_DELAY_MS);
333 <            assertTrue(lock.hasQueuedThreads());
334 <            t1.interrupt();
335 <            Thread.sleep(SHORT_DELAY_MS);
336 <            assertTrue(lock.hasQueuedThreads());
337 <            lock.release();
338 <            Thread.sleep(SHORT_DELAY_MS);
339 <            assertFalse(lock.hasQueuedThreads());
315 <            t1.join();
316 <            t2.join();
317 <        } catch(Exception e){
318 <            unexpectedException();
319 <        }
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       * getQueueLength reports number of waiting threads
343       */
344 <    public void testGetQueueLength() {
345 <        final Semaphore lock = new Semaphore(1, false);
346 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
347 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
348 <        try {
349 <            assertEquals(0, lock.getQueueLength());
350 <            lock.acquireUninterruptibly();
351 <            t1.start();
352 <            Thread.sleep(SHORT_DELAY_MS);
353 <            assertEquals(1, lock.getQueueLength());
354 <            t2.start();
355 <            Thread.sleep(SHORT_DELAY_MS);
356 <            assertEquals(2, lock.getQueueLength());
357 <            t1.interrupt();
358 <            Thread.sleep(SHORT_DELAY_MS);
359 <            assertEquals(1, lock.getQueueLength());
360 <            lock.release();
361 <            Thread.sleep(SHORT_DELAY_MS);
362 <            assertEquals(0, lock.getQueueLength());
344 <            t1.join();
345 <            t2.join();
346 <        } catch(Exception e){
347 <            unexpectedException();
348 <        }
349 <    }
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  
364      /**
365       * getQueuedThreads includes waiting threads
366       */
367 <    public void testGetQueuedThreads() {
368 <        final PublicSemaphore lock = new PublicSemaphore(1, false);
369 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
370 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
371 <        try {
372 <            assertTrue(lock.getQueuedThreads().isEmpty());
373 <            lock.acquireUninterruptibly();
374 <            assertTrue(lock.getQueuedThreads().isEmpty());
375 <            t1.start();
376 <            Thread.sleep(SHORT_DELAY_MS);
377 <            assertTrue(lock.getQueuedThreads().contains(t1));
378 <            t2.start();
379 <            Thread.sleep(SHORT_DELAY_MS);
380 <            assertTrue(lock.getQueuedThreads().contains(t1));
381 <            assertTrue(lock.getQueuedThreads().contains(t2));
382 <            t1.interrupt();
383 <            Thread.sleep(SHORT_DELAY_MS);
384 <            assertFalse(lock.getQueuedThreads().contains(t1));
385 <            assertTrue(lock.getQueuedThreads().contains(t2));
386 <            lock.release();
387 <            Thread.sleep(SHORT_DELAY_MS);
388 <            assertTrue(lock.getQueuedThreads().isEmpty());
376 <            t1.join();
377 <            t2.join();
378 <        } catch(Exception e){
379 <            unexpectedException();
380 <        }
381 <    }
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       * drainPermits reports and removes given number of permits
392       */
393 <    public void testDrainPermits() {
394 <        Semaphore s = new Semaphore(0, false);
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);
# Line 395 | Line 404 | public class SemaphoreTest extends JSR16
404      }
405  
406      /**
407 <     * reducePermits reduces number of permits
399 <     */
400 <    public void testReducePermits() {
401 <        PublicSemaphore s = new PublicSemaphore(10, false);
402 <        assertEquals(10, s.availablePermits());
403 <        s.reducePermits(1);
404 <        assertEquals(9, s.availablePermits());
405 <        s.reducePermits(10);
406 <        assertEquals(-1, s.availablePermits());
407 <    }
408 <
409 <    /**
410 <     * a deserialized serialized semaphore has same number of permits
407 >     * release(-N) throws IllegalArgumentException
408       */
409 <    public void testSerialization() {
410 <        Semaphore l = new Semaphore(3, false);
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 <            l.acquire();
415 <            l.release();
416 <            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
418 <            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
419 <            out.writeObject(l);
420 <            out.close();
421 <
422 <            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
423 <            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
424 <            Semaphore r = (Semaphore) in.readObject();
425 <            assertEquals(3, r.availablePermits());
426 <            assertFalse(r.isFair());
427 <            r.acquire();
428 <            r.release();
429 <        } catch(Exception e){
430 <            unexpectedException();
431 <        }
432 <    }
433 <
434 <
435 <    /**
436 <     * Zero, negative, and positive initial values are allowed in constructor
437 <     */
438 <    public void testConstructor_fair() {
439 <        Semaphore s0 = new Semaphore(0, true);
440 <        assertEquals(0, s0.availablePermits());
441 <        assertTrue(s0.isFair());
442 <        Semaphore s1 = new Semaphore(-1, true);
443 <        assertEquals(-1, s1.availablePermits());
444 <        Semaphore s2 = new Semaphore(-1, true);
445 <        assertEquals(-1, s2.availablePermits());
414 >            s.release(-1);
415 >            shouldThrow();
416 >        } catch (IllegalArgumentException success) {}
417      }
418  
419      /**
420 <     * tryAcquire succeeds when sufficient permits, else fails
420 >     * reducePermits(-N) throws IllegalArgumentException
421       */
422 <    public void testTryAcquireInSameThread_fair() {
423 <        Semaphore s = new Semaphore(2, true);
424 <        assertEquals(2, s.availablePermits());
425 <        assertTrue(s.tryAcquire());
426 <        assertTrue(s.tryAcquire());
427 <        assertEquals(0, s.availablePermits());
428 <        assertFalse(s.tryAcquire());
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 >            s.reducePermits(-1);
428 >            shouldThrow();
429 >        } catch (IllegalArgumentException success) {}
430      }
431  
432      /**
433 <     * tryAcquire(n) succeeds when sufficient permits, else fails
433 >     * reducePermits reduces number of permits
434       */
435 <    public void testTryAcquireNInSameThread_fair() {
436 <        Semaphore s = new Semaphore(2, true);
437 <        assertEquals(2, s.availablePermits());
438 <        assertTrue(s.tryAcquire(2));
439 <        assertEquals(0, s.availablePermits());
440 <        assertFalse(s.tryAcquire());
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 <     * 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();
478            s.release();
462              s.acquire();
463              s.release();
481            s.acquire();
482            s.release();
483            s.acquire();
484            s.release();
485            s.acquire();
486            s.release();
487            assertEquals(1, s.availablePermits());
488        } catch( InterruptedException e){
489            unexpectedException();
490        }
491    }
492
493    /**
494     * Acquire(n) and release(n) of semaphore succeed if initially available
495     */
496    public void testAcquireReleaseNInSameThread_fair() {
497        Semaphore s = new Semaphore(1, true);
498        try {
499            s.release(1);
500            s.acquire(1);
501            s.release(2);
502            s.acquire(2);
503            s.release(3);
504            s.acquire(3);
505            s.release(4);
506            s.acquire(4);
507            s.release(5);
508            s.acquire(5);
509            assertEquals(1, s.availablePermits());
510        } catch( InterruptedException e){
511            unexpectedException();
512        }
513    }
464  
465 <    /**
466 <     * Acquire(n) and release(n) of semaphore succeed if initially available
467 <     */
468 <    public void testAcquireUninterruptiblyReleaseNInSameThread_fair() {
469 <        Semaphore s = new Semaphore(1, true);
470 <        try {
471 <            s.release(1);
472 <            s.acquireUninterruptibly(1);
473 <            s.release(2);
474 <            s.acquireUninterruptibly(2);
475 <            s.release(3);
476 <            s.acquireUninterruptibly(3);
477 <            s.release(4);
478 <            s.acquireUninterruptibly(4);
479 <            s.release(5);
480 <            s.acquireUninterruptibly(5);
481 <            assertEquals(1, s.availablePermits());
482 <        } finally {
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 <     * release(n) in one thread enables timed acquire(n) in another thread
499 >     * tryAcquire(n) succeeds when sufficient permits, else fails
500       */
501 <    public void testTimedAcquireReleaseNInSameThread_fair() {
502 <        Semaphore s = new Semaphore(1, true);
503 <        try {
504 <            s.release(1);
505 <            assertTrue(s.tryAcquire(1, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
506 <            s.release(2);
507 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
508 <            s.release(3);
509 <            assertTrue(s.tryAcquire(3, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
510 <            s.release(4);
511 <            assertTrue(s.tryAcquire(4, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
512 <            s.release(5);
551 <            assertTrue(s.tryAcquire(5, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
552 <            assertEquals(1, s.availablePermits());
553 <        } catch( InterruptedException e){
554 <            unexpectedException();
555 <        }
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 in one thread enables timed acquire in another thread
516 >     * acquire succeeds if permits available
517       */
518 <    public void testTimedAcquireReleaseInSameThread_fair() {
519 <        Semaphore s = new Semaphore(1, true);
520 <        try {
521 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
522 <            s.release();
523 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
524 <            s.release();
525 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
526 <            s.release();
527 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
528 <            s.release();
529 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
530 <            s.release();
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());
575        } catch( InterruptedException e){
576            unexpectedException();
544          }
545      }
546  
547      /**
548 <     * A release in one thread enables an acquire in another thread
548 >     * release in one thread enables acquire in another thread
549       */
550 <    public void testAcquireReleaseInDifferentThreads_fair() {
551 <        final Semaphore s = new Semaphore(0, true);
552 <        Thread t = new Thread(new Runnable() {
553 <                public void run() {
554 <                    try {
555 <                        s.acquire();
556 <                        s.acquire();
557 <                        s.acquire();
558 <                        s.acquire();
559 <                    } catch(InterruptedException ie){
560 <                        threadUnexpectedException();
561 <                    }
562 <                }
563 <            });
564 <        try {
565 <            t.start();
566 <            Thread.sleep(SHORT_DELAY_MS);
567 <            s.release();
568 <            s.release();
569 <            s.release();
570 <            s.release();
571 <            s.release();
572 <            s.release();
573 <            t.join();
574 <            assertEquals(2, s.availablePermits());
575 <        } catch( InterruptedException e){
576 <            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();
600 <                        s.release(2);
601 <                        s.acquire();
602 <                    } catch(InterruptedException ie){
603 <                        threadUnexpectedException();
604 <                    }
605 <                }
606 <            });
607 <        try {
608 <            t.start();
609 <            Thread.sleep(SHORT_DELAY_MS);
610 <            s.release(2);
611 <            s.acquire(2);
612 <            s.release(1);
613 <            t.join();
614 <        } catch( InterruptedException e){
615 <            unexpectedException();
616 <        }
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 <     * release(n) in one thread enables acquire(n) in another thread
635 <     */
636 <    public void testAcquireReleaseNInDifferentThreads_fair2() {
637 <        final Semaphore s = new Semaphore(0, true);
638 <        Thread t = new Thread(new Runnable() {
639 <                public void run() {
640 <                    try {
641 <                        s.acquire(2);
642 <                        s.acquire(2);
643 <                        s.release(4);
644 <                    } catch(InterruptedException ie){
645 <                        threadUnexpectedException();
646 <                    }
655 <                }
656 <            });
657 <        try {
658 <            t.start();
659 <            Thread.sleep(SHORT_DELAY_MS);
660 <            s.release(6);
661 <            s.acquire(2);
662 <            s.acquire(2);
663 <            s.release(2);
664 <            t.join();
665 <        } catch( InterruptedException e){
666 <            unexpectedException();
667 <        }
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  
670
671
672
673
674    /**
675     * release in one thread enables timed acquire in another thread
676     */
677    public void testTimedAcquireReleaseInDifferentThreads_fair() {
678        final Semaphore s = new Semaphore(1, true);
679        Thread t = new Thread(new Runnable() {
680                public void run() {
681                    try {
682                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
683                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
684                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
685                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
686                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
687
688                    } catch(InterruptedException ie){
689                        threadUnexpectedException();
690                    }
691                }
692            });
693        t.start();
694        try {
695            s.release();
696            s.release();
697            s.release();
698            s.release();
699            s.release();
700            t.join();
701        } catch( InterruptedException e){
702            unexpectedException();
703        }
704    }
705
706    /**
707     * release(n) in one thread enables timed acquire(n) in another thread
708     */
709    public void testTimedAcquireReleaseNInDifferentThreads_fair() {
710        final Semaphore s = new Semaphore(2, true);
711        Thread t = new Thread(new Runnable() {
712                public void run() {
713                    try {
714                        threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
715                        s.release(2);
716                        threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
717                        s.release(2);
718                    } catch(InterruptedException ie){
719                        threadUnexpectedException();
720                    }
721                }
722            });
723        t.start();
724        try {
725            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
726            s.release(2);
727            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
728            s.release(2);
729            t.join();
730        } catch( InterruptedException e){
731            unexpectedException();
732        }
733    }
734
735    /**
736     * A waiting acquire blocks interruptibly
737     */
738    public void testAcquire_InterruptedException_fair() {
739        final Semaphore s = new Semaphore(0, true);
740        Thread t = new Thread(new Runnable() {
741                public void run() {
742                    try {
743                        s.acquire();
744                        threadShouldThrow();
745                    } catch(InterruptedException success){}
746                }
747            });
748        t.start();
749        try {
750            Thread.sleep(SHORT_DELAY_MS);
751            t.interrupt();
752            t.join();
753        } catch(InterruptedException e){
754            unexpectedException();
755        }
756    }
757
758    /**
759     * A waiting acquire(n) blocks interruptibly
760     */
761    public void testAcquireN_InterruptedException_fair() {
762        final Semaphore s = new Semaphore(2, true);
763        Thread t = new Thread(new Runnable() {
764                public void run() {
765                    try {
766                        s.acquire(3);
767                        threadShouldThrow();
768                    } catch(InterruptedException success){}
769                }
770            });
771        t.start();
772        try {
773            Thread.sleep(SHORT_DELAY_MS);
774            t.interrupt();
775            t.join();
776        } catch(InterruptedException e){
777            unexpectedException();
778        }
779    }
780    
781    /**
782     *  A waiting tryAcquire blocks interruptibly
783     */
784    public void testTryAcquire_InterruptedException_fair() {
785        final Semaphore s = new Semaphore(0, true);
786        Thread t = new Thread(new Runnable() {
787                public void run() {
788                    try {
789                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
790                        threadShouldThrow();
791                    } catch(InterruptedException success){
792                    }
793                }
794            });
795        t.start();
796        try {
797            Thread.sleep(SHORT_DELAY_MS);
798            t.interrupt();
799            t.join();
800        } catch(InterruptedException e){
801            unexpectedException();
802        }
803    }
804
805    /**
806     *  A waiting tryAcquire(n) blocks interruptibly
807     */
808    public void testTryAcquireN_InterruptedException_fair() {
809        final Semaphore s = new Semaphore(1, true);
810        Thread t = new Thread(new Runnable() {
811                public void run() {
812                    try {
813                        s.tryAcquire(4, MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
814                        threadShouldThrow();
815                    } catch(InterruptedException success){
816                    }
817                }
818            });
819        t.start();
820        try {
821            Thread.sleep(SHORT_DELAY_MS);
822            t.interrupt();
823            t.join();
824        } catch(InterruptedException e){
825            unexpectedException();
826        }
827    }
828
829    /**
830     * getQueueLength reports number of waiting threads
831     */
832    public void testGetQueueLength_fair() {
833        final Semaphore lock = new Semaphore(1, true);
834        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
835        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
836        try {
837            assertEquals(0, lock.getQueueLength());
838            lock.acquireUninterruptibly();
839            t1.start();
840            Thread.sleep(SHORT_DELAY_MS);
841            assertEquals(1, lock.getQueueLength());
842            t2.start();
843            Thread.sleep(SHORT_DELAY_MS);
844            assertEquals(2, lock.getQueueLength());
845            t1.interrupt();
846            Thread.sleep(SHORT_DELAY_MS);
847            assertEquals(1, lock.getQueueLength());
848            lock.release();
849            Thread.sleep(SHORT_DELAY_MS);
850            assertEquals(0, lock.getQueueLength());
851            t1.join();
852            t2.join();
853        } catch(Exception e){
854            unexpectedException();
855        }
856    }
857
858
859    /**
860     * a deserialized serialized semaphore has same number of permits
861     */
862    public void testSerialization_fair() {
863        Semaphore l = new Semaphore(3, true);
864
865        try {
866            l.acquire();
867            l.release();
868            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
869            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
870            out.writeObject(l);
871            out.close();
872
873            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
874            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
875            Semaphore r = (Semaphore) in.readObject();
876            assertEquals(3, r.availablePermits());
877            assertTrue(r.isFair());
878            r.acquire();
879            r.release();
880        } catch(Exception e){
881            unexpectedException();
882        }
883    }
884
885
649   }

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