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Comparing jsr166/src/test/tck/SemaphoreTest.java (file contents):
Revision 1.14 by dl, Sat Jan 10 01:41:59 2004 UTC vs.
Revision 1.40 by jsr166, Sun May 14 03:48:35 2017 UTC

# Line 1 | Line 1
1   /*
2   * Written by Doug Lea with assistance from members of JCP JSR-166
3   * Expert Group and released to the public domain, as explained at
4 < * http://creativecommons.org/licenses/publicdomain
5 < * Other contributors include Andrew Wright, Jeffrey Hayes,
6 < * Pat Fisher, Mike Judd.
4 > * http://creativecommons.org/publicdomain/zero/1.0/
5 > * Other contributors include Andrew Wright, Jeffrey Hayes,
6 > * Pat Fisher, Mike Judd.
7   */
8  
9 < import junit.framework.*;
10 < import java.util.*;
11 < import java.util.concurrent.*;
12 < import java.io.*;
9 > import static java.util.concurrent.TimeUnit.MILLISECONDS;
10 >
11 > import java.util.Collection;
12 > import java.util.concurrent.CountDownLatch;
13 > import java.util.concurrent.Semaphore;
14 > import java.util.concurrent.ThreadLocalRandom;
15 >
16 > import junit.framework.AssertionFailedError;
17 > import junit.framework.Test;
18 > import junit.framework.TestSuite;
19  
20   public class SemaphoreTest extends JSR166TestCase {
21      public static void main(String[] args) {
22 <        junit.textui.TestRunner.run (suite());  
22 >        main(suite(), args);
23      }
24      public static Test suite() {
25 <        return new TestSuite(SemaphoreTest.class);
25 >        return new TestSuite(SemaphoreTest.class);
26      }
27  
28      /**
29       * Subclass to expose protected methods
30       */
31      static class PublicSemaphore extends Semaphore {
32 <        PublicSemaphore(int p, boolean f) { super(p, f); }
33 <        public Collection<Thread> getQueuedThreads() {
34 <            return super.getQueuedThreads();
32 >        PublicSemaphore(int permits) { super(permits); }
33 >        PublicSemaphore(int permits, boolean fair) { super(permits, fair); }
34 >        public Collection<Thread> getQueuedThreads() {
35 >            return super.getQueuedThreads();
36 >        }
37 >        public boolean hasQueuedThread(Thread t) {
38 >            return super.getQueuedThreads().contains(t);
39          }
40 <        public void reducePermits(int p) {
41 <            super.reducePermits(p);
40 >        public void reducePermits(int reduction) {
41 >            super.reducePermits(reduction);
42          }
43      }
44  
45      /**
46       * A runnable calling acquire
47       */
48 <    class InterruptibleLockRunnable implements Runnable {
48 >    class InterruptibleLockRunnable extends CheckedRunnable {
49          final Semaphore lock;
50 <        InterruptibleLockRunnable(Semaphore l) { lock = l; }
51 <        public void run() {
50 >        InterruptibleLockRunnable(Semaphore s) { lock = s; }
51 >        public void realRun() {
52              try {
53                  lock.acquire();
54 <            } catch(InterruptedException success){}
54 >            }
55 >            catch (InterruptedException ignored) {}
56          }
57      }
58  
48
59      /**
60 <     * A runnable calling acquire that expects to be
51 <     * interrupted
60 >     * A runnable calling acquire that expects to be interrupted
61       */
62 <    class InterruptedLockRunnable implements Runnable {
62 >    class InterruptedLockRunnable extends CheckedInterruptedRunnable {
63          final Semaphore lock;
64 <        InterruptedLockRunnable(Semaphore l) { lock = l; }
65 <        public void run() {
66 <            try {
67 <                lock.acquire();
68 <                threadShouldThrow();
69 <            } catch(InterruptedException success){}
64 >        InterruptedLockRunnable(Semaphore s) { lock = s; }
65 >        public void realRun() throws InterruptedException {
66 >            lock.acquire();
67 >        }
68 >    }
69 >
70 >    /**
71 >     * Spin-waits until s.hasQueuedThread(t) becomes true.
72 >     */
73 >    void waitForQueuedThread(PublicSemaphore s, Thread t) {
74 >        long startTime = System.nanoTime();
75 >        while (!s.hasQueuedThread(t)) {
76 >            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
77 >                throw new AssertionFailedError("timed out");
78 >            Thread.yield();
79 >        }
80 >        assertTrue(s.hasQueuedThreads());
81 >        assertTrue(t.isAlive());
82 >    }
83 >
84 >    /**
85 >     * Spin-waits until s.hasQueuedThreads() becomes true.
86 >     */
87 >    void waitForQueuedThreads(Semaphore s) {
88 >        long startTime = System.nanoTime();
89 >        while (!s.hasQueuedThreads()) {
90 >            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
91 >                throw new AssertionFailedError("timed out");
92 >            Thread.yield();
93 >        }
94 >    }
95 >
96 >    enum AcquireMethod {
97 >        acquire() {
98 >            void acquire(Semaphore s) throws InterruptedException {
99 >                s.acquire();
100 >            }
101 >        },
102 >        acquireN() {
103 >            void acquire(Semaphore s, int permits) throws InterruptedException {
104 >                s.acquire(permits);
105 >            }
106 >        },
107 >        acquireUninterruptibly() {
108 >            void acquire(Semaphore s) {
109 >                s.acquireUninterruptibly();
110 >            }
111 >        },
112 >        acquireUninterruptiblyN() {
113 >            void acquire(Semaphore s, int permits) {
114 >                s.acquireUninterruptibly(permits);
115 >            }
116 >        },
117 >        tryAcquire() {
118 >            void acquire(Semaphore s) {
119 >                assertTrue(s.tryAcquire());
120 >            }
121 >        },
122 >        tryAcquireN() {
123 >            void acquire(Semaphore s, int permits) {
124 >                assertTrue(s.tryAcquire(permits));
125 >            }
126 >        },
127 >        tryAcquireTimed() {
128 >            void acquire(Semaphore s) throws InterruptedException {
129 >                assertTrue(s.tryAcquire(2 * LONG_DELAY_MS, MILLISECONDS));
130 >            }
131 >            Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
132 >        },
133 >        tryAcquireTimedN {
134 >            void acquire(Semaphore s, int permits) throws InterruptedException {
135 >                assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS));
136 >            }
137 >            Thread.State parkedState() { return Thread.State.TIMED_WAITING; }
138 >        };
139 >
140 >        // Intentionally meta-circular
141 >
142 >        /** Acquires 1 permit. */
143 >        void acquire(Semaphore s) throws InterruptedException {
144 >            acquire(s, 1);
145 >        }
146 >        /** Acquires the given number of permits. */
147 >        void acquire(Semaphore s, int permits) throws InterruptedException {
148 >            for (int i = 0; i < permits; i++)
149 >                acquire(s);
150          }
151 +        Thread.State parkedState() { return Thread.State.WAITING; }
152      }
153  
154      /**
155       * Zero, negative, and positive initial values are allowed in constructor
156       */
157 <    public void testConstructor() {
158 <        Semaphore s0 = new Semaphore(0, false);
159 <        assertEquals(0, s0.availablePermits());
160 <        assertFalse(s0.isFair());
161 <        Semaphore s1 = new Semaphore(-1, false);
162 <        assertEquals(-1, s1.availablePermits());
163 <        assertFalse(s1.isFair());
164 <        Semaphore s2 = new Semaphore(-1, false);
75 <        assertEquals(-1, s2.availablePermits());
76 <        assertFalse(s2.isFair());
157 >    public void testConstructor()      { testConstructor(false); }
158 >    public void testConstructor_fair() { testConstructor(true); }
159 >    public void testConstructor(boolean fair) {
160 >        for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
161 >            Semaphore s = new Semaphore(permits, fair);
162 >            assertEquals(permits, s.availablePermits());
163 >            assertEquals(fair, s.isFair());
164 >        }
165      }
166  
167      /**
168       * Constructor without fairness argument behaves as nonfair
169       */
170 <    public void testConstructor2() {
171 <        Semaphore s0 = new Semaphore(0);
172 <        assertEquals(0, s0.availablePermits());
173 <        assertFalse(s0.isFair());
174 <        Semaphore s1 = new Semaphore(-1);
175 <        assertEquals(-1, s1.availablePermits());
88 <        assertFalse(s1.isFair());
89 <        Semaphore s2 = new Semaphore(-1);
90 <        assertEquals(-1, s2.availablePermits());
91 <        assertFalse(s2.isFair());
170 >    public void testConstructorDefaultsToNonFair() {
171 >        for (int permits : new int[] { -42, -1, 0, 1, 42 }) {
172 >            Semaphore s = new Semaphore(permits);
173 >            assertEquals(permits, s.availablePermits());
174 >            assertFalse(s.isFair());
175 >        }
176      }
177  
178      /**
179       * tryAcquire succeeds when sufficient permits, else fails
180       */
181 <    public void testTryAcquireInSameThread() {
182 <        Semaphore s = new Semaphore(2, false);
181 >    public void testTryAcquireInSameThread()      { testTryAcquireInSameThread(false); }
182 >    public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); }
183 >    public void testTryAcquireInSameThread(boolean fair) {
184 >        Semaphore s = new Semaphore(2, fair);
185          assertEquals(2, s.availablePermits());
186          assertTrue(s.tryAcquire());
187          assertTrue(s.tryAcquire());
188          assertEquals(0, s.availablePermits());
189          assertFalse(s.tryAcquire());
190 +        assertFalse(s.tryAcquire());
191 +        assertEquals(0, s.availablePermits());
192      }
193  
194      /**
195 <     * Acquire and release of semaphore succeed if initially available
195 >     * timed tryAcquire times out
196       */
197 <    public void testAcquireReleaseInSameThread() {
198 <        Semaphore s = new Semaphore(1, false);
199 <        try {
200 <            s.acquire();
201 <            s.release();
202 <            s.acquire();
203 <            s.release();
204 <            s.acquire();
205 <            s.release();
206 <            s.acquire();
207 <            s.release();
208 <            s.acquire();
209 <            s.release();
210 <            assertEquals(1, s.availablePermits());
211 <        } catch( InterruptedException e){
212 <            unexpectedException();
197 >    public void testTryAcquire_timeout() {
198 >        final boolean fair = ThreadLocalRandom.current().nextBoolean();
199 >        final Semaphore s = new Semaphore(0, fair);
200 >        final long startTime = System.nanoTime();
201 >        try { assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS)); }
202 >        catch (InterruptedException e) { threadUnexpectedException(e); }
203 >        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
204 >    }
205 >
206 >    /**
207 >     * timed tryAcquire(N) times out
208 >     */
209 >    public void testTryAcquireN_timeout() {
210 >        final boolean fair = ThreadLocalRandom.current().nextBoolean();
211 >        final Semaphore s = new Semaphore(2, fair);
212 >        final long startTime = System.nanoTime();
213 >        try { assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS)); }
214 >        catch (InterruptedException e) { threadUnexpectedException(e); }
215 >        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
216 >    }
217 >
218 >    /**
219 >     * acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N)
220 >     * are interruptible
221 >     */
222 >    public void testInterruptible_acquire()               { testInterruptible(false, AcquireMethod.acquire); }
223 >    public void testInterruptible_acquire_fair()          { testInterruptible(true,  AcquireMethod.acquire); }
224 >    public void testInterruptible_acquireN()              { testInterruptible(false, AcquireMethod.acquireN); }
225 >    public void testInterruptible_acquireN_fair()         { testInterruptible(true,  AcquireMethod.acquireN); }
226 >    public void testInterruptible_tryAcquireTimed()       { testInterruptible(false, AcquireMethod.tryAcquireTimed); }
227 >    public void testInterruptible_tryAcquireTimed_fair()  { testInterruptible(true,  AcquireMethod.tryAcquireTimed); }
228 >    public void testInterruptible_tryAcquireTimedN()      { testInterruptible(false, AcquireMethod.tryAcquireTimedN); }
229 >    public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true,  AcquireMethod.tryAcquireTimedN); }
230 >    public void testInterruptible(boolean fair, final AcquireMethod acquirer) {
231 >        final PublicSemaphore s = new PublicSemaphore(0, fair);
232 >        final java.util.concurrent.CyclicBarrier pleaseInterrupt
233 >            = new java.util.concurrent.CyclicBarrier(2);
234 >        Thread t = newStartedThread(new CheckedRunnable() {
235 >            public void realRun() {
236 >                // Interrupt before acquire
237 >                Thread.currentThread().interrupt();
238 >                try {
239 >                    acquirer.acquire(s);
240 >                    shouldThrow();
241 >                } catch (InterruptedException success) {}
242 >                assertFalse(Thread.interrupted());
243 >
244 >                // Interrupt before acquire(N)
245 >                Thread.currentThread().interrupt();
246 >                try {
247 >                    acquirer.acquire(s, 3);
248 >                    shouldThrow();
249 >                } catch (InterruptedException success) {}
250 >                assertFalse(Thread.interrupted());
251 >
252 >                // Interrupt during acquire
253 >                await(pleaseInterrupt);
254 >                try {
255 >                    acquirer.acquire(s);
256 >                    shouldThrow();
257 >                } catch (InterruptedException success) {}
258 >                assertFalse(Thread.interrupted());
259 >
260 >                // Interrupt during acquire(N)
261 >                await(pleaseInterrupt);
262 >                try {
263 >                    acquirer.acquire(s, 3);
264 >                    shouldThrow();
265 >                } catch (InterruptedException success) {}
266 >                assertFalse(Thread.interrupted());
267 >            }});
268 >
269 >        for (int n = 2; n-->0; ) {
270 >            await(pleaseInterrupt);
271 >            assertThreadBlocks(t, acquirer.parkedState());
272 >            t.interrupt();
273          }
274 +        
275 +        awaitTermination(t);
276      }
277  
278      /**
279 <     * Uninterruptible acquire and release of semaphore succeed if
280 <     * initially available
279 >     * acquireUninterruptibly(), acquireUninterruptibly(N) are
280 >     * uninterruptible
281       */
282 <    public void testAcquireUninterruptiblyReleaseInSameThread() {
283 <        Semaphore s = new Semaphore(1, false);
284 <        try {
285 <            s.acquireUninterruptibly();
286 <            s.release();
287 <            s.acquireUninterruptibly();
288 <            s.release();
289 <            s.acquireUninterruptibly();
290 <            s.release();
291 <            s.acquireUninterruptibly();
292 <            s.release();
293 <            s.acquireUninterruptibly();
294 <            s.release();
295 <            assertEquals(1, s.availablePermits());
296 <        } finally {
297 <        }
298 <    }
282 >    public void testUninterruptible_acquireUninterruptibly()       { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); }
283 >    public void testUninterruptible_acquireUninterruptibly_fair()  { testUninterruptible(true,  AcquireMethod.acquireUninterruptibly); }
284 >    public void testUninterruptible_acquireUninterruptiblyN()      { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); }
285 >    public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true,  AcquireMethod.acquireUninterruptiblyN); }
286 >    public void testUninterruptible(boolean fair, final AcquireMethod acquirer) {
287 >        final PublicSemaphore s = new PublicSemaphore(0, fair);
288 >        final Semaphore pleaseInterrupt = new Semaphore(-1, fair);
289 >
290 >        Thread t1 = newStartedThread(new CheckedRunnable() {
291 >            public void realRun() throws InterruptedException {
292 >                // Interrupt before acquire
293 >                pleaseInterrupt.release();
294 >                Thread.currentThread().interrupt();
295 >                acquirer.acquire(s);
296 >                assertTrue(Thread.interrupted());
297 >            }});
298 >
299 >        Thread t2 = newStartedThread(new CheckedRunnable() {
300 >            public void realRun() throws InterruptedException {
301 >                // Interrupt during acquire
302 >                pleaseInterrupt.release();
303 >                acquirer.acquire(s);
304 >                assertTrue(Thread.interrupted());
305 >            }});
306 >
307 >        await(pleaseInterrupt);
308 >        waitForQueuedThread(s, t1);
309 >        waitForQueuedThread(s, t2);
310 >        t2.interrupt();
311  
312 <    /**
313 <     * Timed Acquire and release of semaphore succeed if
152 <     * initially available
153 <     */
154 <    public void testTimedAcquireReleaseInSameThread() {
155 <        Semaphore s = new Semaphore(1, false);
156 <        try {
157 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
158 <            s.release();
159 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
160 <            s.release();
161 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
162 <            s.release();
163 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
164 <            s.release();
165 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
166 <            s.release();
167 <            assertEquals(1, s.availablePermits());
168 <        } catch( InterruptedException e){
169 <            unexpectedException();
170 <        }
171 <    }
312 >        assertThreadBlocks(t1, Thread.State.WAITING);
313 >        assertThreadBlocks(t2, Thread.State.WAITING);
314  
315 <    /**
174 <     * A release in one thread enables an acquire in another thread
175 <     */
176 <    public void testAcquireReleaseInDifferentThreads() {
177 <        final Semaphore s = new Semaphore(0, false);
178 <        Thread t = new Thread(new Runnable() {
179 <                public void run() {
180 <                    try {
181 <                        s.acquire();
182 <                        s.release();
183 <                        s.release();
184 <                        s.acquire();
185 <                    } catch(InterruptedException ie){
186 <                        threadUnexpectedException();
187 <                    }
188 <                }
189 <            });
190 <        try {
191 <            t.start();
192 <            Thread.sleep(SHORT_DELAY_MS);
193 <            s.release();
194 <            s.release();
195 <            s.acquire();
196 <            s.acquire();
197 <            s.release();
198 <            t.join();
199 <        } catch( InterruptedException e){
200 <            unexpectedException();
201 <        }
202 <    }
315 >        s.release(2);
316  
317 <    /**
318 <     * A release in one thread enables an uninterruptible acquire in another thread
206 <     */
207 <    public void testUninterruptibleAcquireReleaseInDifferentThreads() {
208 <        final Semaphore s = new Semaphore(0, false);
209 <        Thread t = new Thread(new Runnable() {
210 <                public void run() {
211 <                    s.acquireUninterruptibly();
212 <                    s.release();
213 <                    s.release();
214 <                    s.acquireUninterruptibly();
215 <                }
216 <            });
217 <        try {
218 <            t.start();
219 <            Thread.sleep(SHORT_DELAY_MS);
220 <            s.release();
221 <            s.release();
222 <            s.acquireUninterruptibly();
223 <            s.acquireUninterruptibly();
224 <            s.release();
225 <            t.join();
226 <        } catch( InterruptedException e){
227 <            unexpectedException();
228 <        }
229 <    }
230 <
231 <
232 <    /**
233 <     *  A release in one thread enables a timed acquire in another thread
234 <     */
235 <    public void testTimedAcquireReleaseInDifferentThreads() {
236 <        final Semaphore s = new Semaphore(1, false);
237 <        Thread t = new Thread(new Runnable() {
238 <                public void run() {
239 <                    try {
240 <                        s.release();
241 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
242 <                        s.release();
243 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
244 <
245 <                    } catch(InterruptedException ie){
246 <                        threadUnexpectedException();
247 <                    }
248 <                }
249 <            });
250 <        try {
251 <            t.start();
252 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
253 <            s.release();
254 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
255 <            s.release();
256 <            s.release();
257 <            t.join();
258 <        } catch( InterruptedException e){
259 <            unexpectedException();
260 <        }
261 <    }
262 <
263 <    /**
264 <     * A waiting acquire blocks interruptibly
265 <     */
266 <    public void testAcquire_InterruptedException() {
267 <        final Semaphore s = new Semaphore(0, false);
268 <        Thread t = new Thread(new Runnable() {
269 <                public void run() {
270 <                    try {
271 <                        s.acquire();
272 <                        threadShouldThrow();
273 <                    } catch(InterruptedException success){}
274 <                }
275 <            });
276 <        t.start();
277 <        try {
278 <            Thread.sleep(SHORT_DELAY_MS);
279 <            t.interrupt();
280 <            t.join();
281 <        } catch(InterruptedException e){
282 <            unexpectedException();
283 <        }
284 <    }
285 <    
286 <    /**
287 <     *  A waiting timed acquire blocks interruptibly
288 <     */
289 <    public void testTryAcquire_InterruptedException() {
290 <        final Semaphore s = new Semaphore(0, false);
291 <        Thread t = new Thread(new Runnable() {
292 <                public void run() {
293 <                    try {
294 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
295 <                        threadShouldThrow();
296 <                    } catch(InterruptedException success){
297 <                    }
298 <                }
299 <            });
300 <        t.start();
301 <        try {
302 <            Thread.sleep(SHORT_DELAY_MS);
303 <            t.interrupt();
304 <            t.join();
305 <        } catch(InterruptedException e){
306 <            unexpectedException();
307 <        }
317 >        awaitTermination(t1);
318 >        awaitTermination(t2);
319      }
320  
321      /**
322       * hasQueuedThreads reports whether there are waiting threads
323       */
324 <    public void testHasQueuedThreads() {
325 <        final Semaphore lock = new Semaphore(1, false);
326 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
327 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
328 <        try {
329 <            assertFalse(lock.hasQueuedThreads());
330 <            lock.acquireUninterruptibly();
331 <            t1.start();
332 <            Thread.sleep(SHORT_DELAY_MS);
333 <            assertTrue(lock.hasQueuedThreads());
334 <            t2.start();
335 <            Thread.sleep(SHORT_DELAY_MS);
336 <            assertTrue(lock.hasQueuedThreads());
337 <            t1.interrupt();
338 <            Thread.sleep(SHORT_DELAY_MS);
339 <            assertTrue(lock.hasQueuedThreads());
340 <            lock.release();
341 <            Thread.sleep(SHORT_DELAY_MS);
342 <            assertFalse(lock.hasQueuedThreads());
332 <            t1.join();
333 <            t2.join();
334 <        } catch(Exception e){
335 <            unexpectedException();
336 <        }
337 <    }
324 >    public void testHasQueuedThreads()      { testHasQueuedThreads(false); }
325 >    public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); }
326 >    public void testHasQueuedThreads(boolean fair) {
327 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
328 >        assertFalse(lock.hasQueuedThreads());
329 >        lock.acquireUninterruptibly();
330 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
331 >        waitForQueuedThread(lock, t1);
332 >        assertTrue(lock.hasQueuedThreads());
333 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
334 >        waitForQueuedThread(lock, t2);
335 >        assertTrue(lock.hasQueuedThreads());
336 >        t1.interrupt();
337 >        awaitTermination(t1);
338 >        assertTrue(lock.hasQueuedThreads());
339 >        lock.release();
340 >        awaitTermination(t2);
341 >        assertFalse(lock.hasQueuedThreads());
342 >    }
343  
344      /**
345       * getQueueLength reports number of waiting threads
346       */
347 <    public void testGetQueueLength() {
348 <        final Semaphore lock = new Semaphore(1, false);
349 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
350 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
351 <        try {
352 <            assertEquals(0, lock.getQueueLength());
353 <            lock.acquireUninterruptibly();
354 <            t1.start();
355 <            Thread.sleep(SHORT_DELAY_MS);
356 <            assertEquals(1, lock.getQueueLength());
357 <            t2.start();
358 <            Thread.sleep(SHORT_DELAY_MS);
359 <            assertEquals(2, lock.getQueueLength());
360 <            t1.interrupt();
361 <            Thread.sleep(SHORT_DELAY_MS);
362 <            assertEquals(1, lock.getQueueLength());
363 <            lock.release();
364 <            Thread.sleep(SHORT_DELAY_MS);
365 <            assertEquals(0, lock.getQueueLength());
361 <            t1.join();
362 <            t2.join();
363 <        } catch(Exception e){
364 <            unexpectedException();
365 <        }
366 <    }
347 >    public void testGetQueueLength()      { testGetQueueLength(false); }
348 >    public void testGetQueueLength_fair() { testGetQueueLength(true); }
349 >    public void testGetQueueLength(boolean fair) {
350 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
351 >        assertEquals(0, lock.getQueueLength());
352 >        lock.acquireUninterruptibly();
353 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
354 >        waitForQueuedThread(lock, t1);
355 >        assertEquals(1, lock.getQueueLength());
356 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
357 >        waitForQueuedThread(lock, t2);
358 >        assertEquals(2, lock.getQueueLength());
359 >        t1.interrupt();
360 >        awaitTermination(t1);
361 >        assertEquals(1, lock.getQueueLength());
362 >        lock.release();
363 >        awaitTermination(t2);
364 >        assertEquals(0, lock.getQueueLength());
365 >    }
366  
367      /**
368       * getQueuedThreads includes waiting threads
369       */
370 <    public void testGetQueuedThreads() {
371 <        final PublicSemaphore lock = new PublicSemaphore(1, false);
372 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
373 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
374 <        try {
375 <            assertTrue(lock.getQueuedThreads().isEmpty());
376 <            lock.acquireUninterruptibly();
377 <            assertTrue(lock.getQueuedThreads().isEmpty());
378 <            t1.start();
379 <            Thread.sleep(SHORT_DELAY_MS);
380 <            assertTrue(lock.getQueuedThreads().contains(t1));
381 <            t2.start();
382 <            Thread.sleep(SHORT_DELAY_MS);
383 <            assertTrue(lock.getQueuedThreads().contains(t1));
384 <            assertTrue(lock.getQueuedThreads().contains(t2));
385 <            t1.interrupt();
386 <            Thread.sleep(SHORT_DELAY_MS);
387 <            assertFalse(lock.getQueuedThreads().contains(t1));
388 <            assertTrue(lock.getQueuedThreads().contains(t2));
389 <            lock.release();
390 <            Thread.sleep(SHORT_DELAY_MS);
391 <            assertTrue(lock.getQueuedThreads().isEmpty());
393 <            t1.join();
394 <            t2.join();
395 <        } catch(Exception e){
396 <            unexpectedException();
397 <        }
398 <    }
370 >    public void testGetQueuedThreads()      { testGetQueuedThreads(false); }
371 >    public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); }
372 >    public void testGetQueuedThreads(boolean fair) {
373 >        final PublicSemaphore lock = new PublicSemaphore(1, fair);
374 >        assertTrue(lock.getQueuedThreads().isEmpty());
375 >        lock.acquireUninterruptibly();
376 >        assertTrue(lock.getQueuedThreads().isEmpty());
377 >        Thread t1 = newStartedThread(new InterruptedLockRunnable(lock));
378 >        waitForQueuedThread(lock, t1);
379 >        assertTrue(lock.getQueuedThreads().contains(t1));
380 >        Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock));
381 >        waitForQueuedThread(lock, t2);
382 >        assertTrue(lock.getQueuedThreads().contains(t1));
383 >        assertTrue(lock.getQueuedThreads().contains(t2));
384 >        t1.interrupt();
385 >        awaitTermination(t1);
386 >        assertFalse(lock.getQueuedThreads().contains(t1));
387 >        assertTrue(lock.getQueuedThreads().contains(t2));
388 >        lock.release();
389 >        awaitTermination(t2);
390 >        assertTrue(lock.getQueuedThreads().isEmpty());
391 >    }
392  
393      /**
394       * drainPermits reports and removes given number of permits
395       */
396 <    public void testDrainPermits() {
397 <        Semaphore s = new Semaphore(0, false);
396 >    public void testDrainPermits()      { testDrainPermits(false); }
397 >    public void testDrainPermits_fair() { testDrainPermits(true); }
398 >    public void testDrainPermits(boolean fair) {
399 >        Semaphore s = new Semaphore(0, fair);
400          assertEquals(0, s.availablePermits());
401          assertEquals(0, s.drainPermits());
402          s.release(10);
# Line 412 | Line 407 | public class SemaphoreTest extends JSR16
407      }
408  
409      /**
410 <     * reducePermits reduces number of permits
410 >     * release(-N) throws IllegalArgumentException
411       */
412 <    public void testReducePermits() {
413 <        PublicSemaphore s = new PublicSemaphore(10, false);
414 <        assertEquals(10, s.availablePermits());
415 <        s.reducePermits(1);
421 <        assertEquals(9, s.availablePermits());
422 <        s.reducePermits(10);
423 <        assertEquals(-1, s.availablePermits());
424 <    }
425 <
426 <    /**
427 <     * a deserialized serialized semaphore has same number of permits
428 <     */
429 <    public void testSerialization() {
430 <        Semaphore l = new Semaphore(3, false);
412 >    public void testReleaseIAE()      { testReleaseIAE(false); }
413 >    public void testReleaseIAE_fair() { testReleaseIAE(true); }
414 >    public void testReleaseIAE(boolean fair) {
415 >        Semaphore s = new Semaphore(10, fair);
416          try {
417 <            l.acquire();
418 <            l.release();
419 <            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
435 <            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
436 <            out.writeObject(l);
437 <            out.close();
438 <
439 <            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
440 <            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
441 <            Semaphore r = (Semaphore) in.readObject();
442 <            assertEquals(3, r.availablePermits());
443 <            assertFalse(r.isFair());
444 <            r.acquire();
445 <            r.release();
446 <        } catch(Exception e){
447 <            unexpectedException();
448 <        }
449 <    }
450 <
451 <
452 <    /**
453 <     * Zero, negative, and positive initial values are allowed in constructor
454 <     */
455 <    public void testConstructor_fair() {
456 <        Semaphore s0 = new Semaphore(0, true);
457 <        assertEquals(0, s0.availablePermits());
458 <        assertTrue(s0.isFair());
459 <        Semaphore s1 = new Semaphore(-1, true);
460 <        assertEquals(-1, s1.availablePermits());
461 <        Semaphore s2 = new Semaphore(-1, true);
462 <        assertEquals(-1, s2.availablePermits());
417 >            s.release(-1);
418 >            shouldThrow();
419 >        } catch (IllegalArgumentException success) {}
420      }
421  
422      /**
423 <     * tryAcquire succeeds when sufficient permits, else fails
423 >     * reducePermits(-N) throws IllegalArgumentException
424       */
425 <    public void testTryAcquireInSameThread_fair() {
426 <        Semaphore s = new Semaphore(2, true);
427 <        assertEquals(2, s.availablePermits());
428 <        assertTrue(s.tryAcquire());
429 <        assertTrue(s.tryAcquire());
430 <        assertEquals(0, s.availablePermits());
431 <        assertFalse(s.tryAcquire());
425 >    public void testReducePermitsIAE()      { testReducePermitsIAE(false); }
426 >    public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); }
427 >    public void testReducePermitsIAE(boolean fair) {
428 >        PublicSemaphore s = new PublicSemaphore(10, fair);
429 >        try {
430 >            s.reducePermits(-1);
431 >            shouldThrow();
432 >        } catch (IllegalArgumentException success) {}
433      }
434  
435      /**
436 <     * tryAcquire(n) succeeds when sufficient permits, else fails
436 >     * reducePermits reduces number of permits
437       */
438 <    public void testTryAcquireNInSameThread_fair() {
439 <        Semaphore s = new Semaphore(2, true);
440 <        assertEquals(2, s.availablePermits());
441 <        assertTrue(s.tryAcquire(2));
442 <        assertEquals(0, s.availablePermits());
443 <        assertFalse(s.tryAcquire());
438 >    public void testReducePermits()      { testReducePermits(false); }
439 >    public void testReducePermits_fair() { testReducePermits(true); }
440 >    public void testReducePermits(boolean fair) {
441 >        PublicSemaphore s = new PublicSemaphore(10, fair);
442 >        assertEquals(10, s.availablePermits());
443 >        s.reducePermits(0);
444 >        assertEquals(10, s.availablePermits());
445 >        s.reducePermits(1);
446 >        assertEquals(9, s.availablePermits());
447 >        s.reducePermits(10);
448 >        assertEquals(-1, s.availablePermits());
449 >        s.reducePermits(10);
450 >        assertEquals(-11, s.availablePermits());
451 >        s.reducePermits(0);
452 >        assertEquals(-11, s.availablePermits());
453      }
454  
455      /**
456 <     * Acquire and release of semaphore succeed if initially available
456 >     * a reserialized semaphore has same number of permits and
457 >     * fairness, but no queued threads
458       */
459 <    public void testAcquireReleaseInSameThread_fair() {
460 <        Semaphore s = new Semaphore(1, true);
459 >    public void testSerialization()      { testSerialization(false); }
460 >    public void testSerialization_fair() { testSerialization(true); }
461 >    public void testSerialization(boolean fair) {
462          try {
463 +            Semaphore s = new Semaphore(3, fair);
464              s.acquire();
495            s.release();
465              s.acquire();
466              s.release();
498            s.acquire();
499            s.release();
500            s.acquire();
501            s.release();
502            s.acquire();
503            s.release();
504            assertEquals(1, s.availablePermits());
505        } catch( InterruptedException e){
506            unexpectedException();
507        }
508    }
509
510    /**
511     * Acquire(n) and release(n) of semaphore succeed if initially available
512     */
513    public void testAcquireReleaseNInSameThread_fair() {
514        Semaphore s = new Semaphore(1, true);
515        try {
516            s.release(1);
517            s.acquire(1);
518            s.release(2);
519            s.acquire(2);
520            s.release(3);
521            s.acquire(3);
522            s.release(4);
523            s.acquire(4);
524            s.release(5);
525            s.acquire(5);
526            assertEquals(1, s.availablePermits());
527        } catch( InterruptedException e){
528            unexpectedException();
529        }
530    }
467  
468 <    /**
469 <     * Acquire(n) and release(n) of semaphore succeed if initially available
470 <     */
471 <    public void testAcquireUninterruptiblyReleaseNInSameThread_fair() {
472 <        Semaphore s = new Semaphore(1, true);
473 <        try {
474 <            s.release(1);
475 <            s.acquireUninterruptibly(1);
476 <            s.release(2);
477 <            s.acquireUninterruptibly(2);
478 <            s.release(3);
479 <            s.acquireUninterruptibly(3);
480 <            s.release(4);
481 <            s.acquireUninterruptibly(4);
482 <            s.release(5);
483 <            s.acquireUninterruptibly(5);
484 <            assertEquals(1, s.availablePermits());
485 <        } finally {
468 >            Semaphore clone = serialClone(s);
469 >            assertEquals(fair, s.isFair());
470 >            assertEquals(fair, clone.isFair());
471 >            assertEquals(2, s.availablePermits());
472 >            assertEquals(2, clone.availablePermits());
473 >            clone.acquire();
474 >            clone.acquire();
475 >            clone.release();
476 >            assertEquals(2, s.availablePermits());
477 >            assertEquals(1, clone.availablePermits());
478 >            assertFalse(s.hasQueuedThreads());
479 >            assertFalse(clone.hasQueuedThreads());
480 >        } catch (InterruptedException e) { threadUnexpectedException(e); }
481 >
482 >        {
483 >            PublicSemaphore s = new PublicSemaphore(0, fair);
484 >            Thread t = newStartedThread(new InterruptibleLockRunnable(s));
485 >            // waitForQueuedThreads(s); // suffers from "flicker", so ...
486 >            waitForQueuedThread(s, t);  // ... we use this instead
487 >            PublicSemaphore clone = serialClone(s);
488 >            assertEquals(fair, s.isFair());
489 >            assertEquals(fair, clone.isFair());
490 >            assertEquals(0, s.availablePermits());
491 >            assertEquals(0, clone.availablePermits());
492 >            assertTrue(s.hasQueuedThreads());
493 >            assertFalse(clone.hasQueuedThreads());
494 >            s.release();
495 >            awaitTermination(t);
496 >            assertFalse(s.hasQueuedThreads());
497 >            assertFalse(clone.hasQueuedThreads());
498          }
499      }
500  
501      /**
502 <     * release(n) in one thread enables timed acquire(n) in another thread
502 >     * tryAcquire(n) succeeds when sufficient permits, else fails
503       */
504 <    public void testTimedAcquireReleaseNInSameThread_fair() {
505 <        Semaphore s = new Semaphore(1, true);
506 <        try {
507 <            s.release(1);
508 <            assertTrue(s.tryAcquire(1, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
509 <            s.release(2);
510 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
511 <            s.release(3);
512 <            assertTrue(s.tryAcquire(3, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
513 <            s.release(4);
514 <            assertTrue(s.tryAcquire(4, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
515 <            s.release(5);
568 <            assertTrue(s.tryAcquire(5, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
569 <            assertEquals(1, s.availablePermits());
570 <        } catch( InterruptedException e){
571 <            unexpectedException();
572 <        }
504 >    public void testTryAcquireNInSameThread()      { testTryAcquireNInSameThread(false); }
505 >    public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); }
506 >    public void testTryAcquireNInSameThread(boolean fair) {
507 >        Semaphore s = new Semaphore(2, fair);
508 >        assertEquals(2, s.availablePermits());
509 >        assertFalse(s.tryAcquire(3));
510 >        assertEquals(2, s.availablePermits());
511 >        assertTrue(s.tryAcquire(2));
512 >        assertEquals(0, s.availablePermits());
513 >        assertFalse(s.tryAcquire(1));
514 >        assertFalse(s.tryAcquire(2));
515 >        assertEquals(0, s.availablePermits());
516      }
517  
518      /**
519 <     * release in one thread enables timed acquire in another thread
519 >     * acquire succeeds if permits available
520       */
521 <    public void testTimedAcquireReleaseInSameThread_fair() {
522 <        Semaphore s = new Semaphore(1, true);
523 <        try {
524 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
525 <            s.release();
526 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
527 <            s.release();
528 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
529 <            s.release();
530 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
531 <            s.release();
532 <            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
533 <            s.release();
521 >    public void testReleaseAcquireSameThread_acquire()       { testReleaseAcquireSameThread(false, AcquireMethod.acquire); }
522 >    public void testReleaseAcquireSameThread_acquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquire); }
523 >    public void testReleaseAcquireSameThread_acquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); }
524 >    public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); }
525 >    public void testReleaseAcquireSameThread_acquireUninterruptibly()       { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
526 >    public void testReleaseAcquireSameThread_acquireUninterruptibly_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
527 >    public void testReleaseAcquireSameThread_acquireUninterruptiblyN()      { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); }
528 >    public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); }
529 >    public void testReleaseAcquireSameThread_tryAcquire()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); }
530 >    public void testReleaseAcquireSameThread_tryAcquire_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); }
531 >    public void testReleaseAcquireSameThread_tryAcquireN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); }
532 >    public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); }
533 >    public void testReleaseAcquireSameThread_tryAcquireTimed()       { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); }
534 >    public void testReleaseAcquireSameThread_tryAcquireTimed_fair()  { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); }
535 >    public void testReleaseAcquireSameThread_tryAcquireTimedN()      { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); }
536 >    public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); }
537 >    public void testReleaseAcquireSameThread(boolean fair,
538 >                                             final AcquireMethod acquirer) {
539 >        Semaphore s = new Semaphore(1, fair);
540 >        for (int i = 1; i < 6; i++) {
541 >            s.release(i);
542 >            assertEquals(1 + i, s.availablePermits());
543 >            try {
544 >                acquirer.acquire(s, i);
545 >            } catch (InterruptedException e) { threadUnexpectedException(e); }
546              assertEquals(1, s.availablePermits());
592        } catch( InterruptedException e){
593            unexpectedException();
547          }
548      }
549  
550      /**
551 <     * A release in one thread enables an acquire in another thread
551 >     * release in one thread enables acquire in another thread
552       */
553 <    public void testAcquireReleaseInDifferentThreads_fair() {
554 <        final Semaphore s = new Semaphore(0, true);
555 <        Thread t = new Thread(new Runnable() {
556 <                public void run() {
557 <                    try {
558 <                        s.acquire();
559 <                        s.acquire();
560 <                        s.acquire();
561 <                        s.acquire();
562 <                    } catch(InterruptedException ie){
563 <                        threadUnexpectedException();
564 <                    }
565 <                }
566 <            });
567 <        try {
568 <            t.start();
569 <            Thread.sleep(SHORT_DELAY_MS);
570 <            s.release();
571 <            s.release();
572 <            s.release();
573 <            s.release();
574 <            s.release();
575 <            s.release();
576 <            t.join();
577 <            assertEquals(2, s.availablePermits());
578 <        } catch( InterruptedException e){
579 <            unexpectedException();
580 <        }
581 <    }
582 <
583 <    /**
584 <     * release(n) in one thread enables acquire(n) in another thread
585 <     */
586 <    public void testAcquireReleaseNInDifferentThreads_fair() {
587 <        final Semaphore s = new Semaphore(0, true);
635 <        Thread t = new Thread(new Runnable() {
636 <                public void run() {
637 <                    try {
638 <                        s.acquire();
639 <                        s.release(2);
640 <                        s.acquire();
641 <                    } catch(InterruptedException ie){
642 <                        threadUnexpectedException();
643 <                    }
644 <                }
645 <            });
646 <        try {
647 <            t.start();
648 <            Thread.sleep(SHORT_DELAY_MS);
649 <            s.release(2);
650 <            s.acquire(2);
651 <            s.release(1);
652 <            t.join();
653 <        } catch( InterruptedException e){
654 <            unexpectedException();
655 <        }
656 <    }
657 <
658 <    /**
659 <     * release(n) in one thread enables acquire(n) in another thread
660 <     */
661 <    public void testAcquireReleaseNInDifferentThreads_fair2() {
662 <        final Semaphore s = new Semaphore(0, true);
663 <        Thread t = new Thread(new Runnable() {
664 <                public void run() {
665 <                    try {
666 <                        s.acquire(2);
667 <                        s.acquire(2);
668 <                        s.release(4);
669 <                    } catch(InterruptedException ie){
670 <                        threadUnexpectedException();
671 <                    }
672 <                }
673 <            });
674 <        try {
675 <            t.start();
676 <            Thread.sleep(SHORT_DELAY_MS);
677 <            s.release(6);
678 <            s.acquire(2);
679 <            s.acquire(2);
680 <            s.release(2);
681 <            t.join();
682 <        } catch( InterruptedException e){
683 <            unexpectedException();
684 <        }
685 <    }
686 <
687 <
688 <
689 <
690 <
691 <    /**
692 <     * release in one thread enables timed acquire in another thread
693 <     */
694 <    public void testTimedAcquireReleaseInDifferentThreads_fair() {
695 <        final Semaphore s = new Semaphore(1, true);
696 <        Thread t = new Thread(new Runnable() {
697 <                public void run() {
698 <                    try {
699 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
700 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
701 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
702 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
703 <                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
704 <
705 <                    } catch(InterruptedException ie){
706 <                        threadUnexpectedException();
707 <                    }
708 <                }
709 <            });
710 <        t.start();
711 <        try {
712 <            s.release();
713 <            s.release();
714 <            s.release();
715 <            s.release();
716 <            s.release();
717 <            t.join();
718 <        } catch( InterruptedException e){
719 <            unexpectedException();
720 <        }
721 <    }
722 <
723 <    /**
724 <     * release(n) in one thread enables timed acquire(n) in another thread
725 <     */
726 <    public void testTimedAcquireReleaseNInDifferentThreads_fair() {
727 <        final Semaphore s = new Semaphore(2, true);
728 <        Thread t = new Thread(new Runnable() {
729 <                public void run() {
730 <                    try {
731 <                        threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
732 <                        s.release(2);
733 <                        threadAssertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
734 <                        s.release(2);
735 <                    } catch(InterruptedException ie){
736 <                        threadUnexpectedException();
737 <                    }
738 <                }
739 <            });
740 <        t.start();
741 <        try {
742 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
743 <            s.release(2);
744 <            assertTrue(s.tryAcquire(2, SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
745 <            s.release(2);
746 <            t.join();
747 <        } catch( InterruptedException e){
748 <            unexpectedException();
749 <        }
750 <    }
751 <
752 <    /**
753 <     * A waiting acquire blocks interruptibly
754 <     */
755 <    public void testAcquire_InterruptedException_fair() {
756 <        final Semaphore s = new Semaphore(0, true);
757 <        Thread t = new Thread(new Runnable() {
758 <                public void run() {
759 <                    try {
760 <                        s.acquire();
761 <                        threadShouldThrow();
762 <                    } catch(InterruptedException success){}
763 <                }
764 <            });
765 <        t.start();
766 <        try {
767 <            Thread.sleep(SHORT_DELAY_MS);
768 <            t.interrupt();
769 <            t.join();
770 <        } catch(InterruptedException e){
771 <            unexpectedException();
772 <        }
773 <    }
774 <
775 <    /**
776 <     * A waiting acquire(n) blocks interruptibly
777 <     */
778 <    public void testAcquireN_InterruptedException_fair() {
779 <        final Semaphore s = new Semaphore(2, true);
780 <        Thread t = new Thread(new Runnable() {
781 <                public void run() {
782 <                    try {
783 <                        s.acquire(3);
784 <                        threadShouldThrow();
785 <                    } catch(InterruptedException success){}
786 <                }
787 <            });
788 <        t.start();
789 <        try {
790 <            Thread.sleep(SHORT_DELAY_MS);
791 <            t.interrupt();
792 <            t.join();
793 <        } catch(InterruptedException e){
794 <            unexpectedException();
795 <        }
796 <    }
797 <    
798 <    /**
799 <     *  A waiting tryAcquire blocks interruptibly
800 <     */
801 <    public void testTryAcquire_InterruptedException_fair() {
802 <        final Semaphore s = new Semaphore(0, true);
803 <        Thread t = new Thread(new Runnable() {
804 <                public void run() {
805 <                    try {
806 <                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
807 <                        threadShouldThrow();
808 <                    } catch(InterruptedException success){
809 <                    }
810 <                }
811 <            });
812 <        t.start();
813 <        try {
814 <            Thread.sleep(SHORT_DELAY_MS);
815 <            t.interrupt();
816 <            t.join();
817 <        } catch(InterruptedException e){
818 <            unexpectedException();
819 <        }
820 <    }
821 <
822 <    /**
823 <     *  A waiting tryAcquire(n) blocks interruptibly
824 <     */
825 <    public void testTryAcquireN_InterruptedException_fair() {
826 <        final Semaphore s = new Semaphore(1, true);
827 <        Thread t = new Thread(new Runnable() {
828 <                public void run() {
829 <                    try {
830 <                        s.tryAcquire(4, MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
831 <                        threadShouldThrow();
832 <                    } catch(InterruptedException success){
833 <                    }
834 <                }
835 <            });
836 <        t.start();
837 <        try {
838 <            Thread.sleep(SHORT_DELAY_MS);
839 <            t.interrupt();
840 <            t.join();
841 <        } catch(InterruptedException e){
842 <            unexpectedException();
553 >    public void testReleaseAcquireDifferentThreads_acquire()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); }
554 >    public void testReleaseAcquireDifferentThreads_acquire_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); }
555 >    public void testReleaseAcquireDifferentThreads_acquireN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); }
556 >    public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); }
557 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptibly()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
558 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
559 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); }
560 >    public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); }
561 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimed()       { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); }
562 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair()  { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); }
563 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimedN()      { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); }
564 >    public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); }
565 >    public void testReleaseAcquireDifferentThreads(boolean fair,
566 >                                                   final AcquireMethod acquirer) {
567 >        final Semaphore s = new Semaphore(0, fair);
568 >        final int rounds = 4;
569 >        long startTime = System.nanoTime();
570 >        Thread t = newStartedThread(new CheckedRunnable() {
571 >            public void realRun() throws InterruptedException {
572 >                for (int i = 0; i < rounds; i++) {
573 >                    assertFalse(s.hasQueuedThreads());
574 >                    if (i % 2 == 0)
575 >                        acquirer.acquire(s);
576 >                    else
577 >                        acquirer.acquire(s, 3);
578 >                }}});
579 >
580 >        for (int i = 0; i < rounds; i++) {
581 >            while (! (s.availablePermits() == 0 && s.hasQueuedThreads()))
582 >                Thread.yield();
583 >            assertTrue(t.isAlive());
584 >            if (i % 2 == 0)
585 >                s.release();
586 >            else
587 >                s.release(3);
588          }
589 +        awaitTermination(t);
590 +        assertEquals(0, s.availablePermits());
591 +        assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS);
592      }
593  
594      /**
595 <     * getQueueLength reports number of waiting threads
848 <     */
849 <    public void testGetQueueLength_fair() {
850 <        final Semaphore lock = new Semaphore(1, true);
851 <        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
852 <        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
853 <        try {
854 <            assertEquals(0, lock.getQueueLength());
855 <            lock.acquireUninterruptibly();
856 <            t1.start();
857 <            Thread.sleep(SHORT_DELAY_MS);
858 <            assertEquals(1, lock.getQueueLength());
859 <            t2.start();
860 <            Thread.sleep(SHORT_DELAY_MS);
861 <            assertEquals(2, lock.getQueueLength());
862 <            t1.interrupt();
863 <            Thread.sleep(SHORT_DELAY_MS);
864 <            assertEquals(1, lock.getQueueLength());
865 <            lock.release();
866 <            Thread.sleep(SHORT_DELAY_MS);
867 <            assertEquals(0, lock.getQueueLength());
868 <            t1.join();
869 <            t2.join();
870 <        } catch(Exception e){
871 <            unexpectedException();
872 <        }
873 <    }
874 <
875 <
876 <    /**
877 <     * a deserialized serialized semaphore has same number of permits
595 >     * fair locks are strictly FIFO
596       */
597 <    public void testSerialization_fair() {
598 <        Semaphore l = new Semaphore(3, true);
599 <
600 <        try {
601 <            l.acquire();
602 <            l.release();
603 <            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
604 <            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
605 <            out.writeObject(l);
606 <            out.close();
607 <
608 <            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
609 <            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
610 <            Semaphore r = (Semaphore) in.readObject();
611 <            assertEquals(3, r.availablePermits());
612 <            assertTrue(r.isFair());
613 <            r.acquire();
614 <            r.release();
615 <        } catch(Exception e){
616 <            unexpectedException();
617 <        }
597 >    public void testFairLocksFifo() {
598 >        final PublicSemaphore s = new PublicSemaphore(1, true);
599 >        final CountDownLatch pleaseRelease = new CountDownLatch(1);
600 >        Thread t1 = newStartedThread(new CheckedRunnable() {
601 >            public void realRun() throws InterruptedException {
602 >                // Will block; permits are available, but not three
603 >                s.acquire(3);
604 >            }});
605 >
606 >        waitForQueuedThread(s, t1);
607 >
608 >        Thread t2 = newStartedThread(new CheckedRunnable() {
609 >            public void realRun() throws InterruptedException {
610 >                // Will fail, even though 1 permit is available
611 >                assertFalse(s.tryAcquire(0L, MILLISECONDS));
612 >                assertFalse(s.tryAcquire(1, 0L, MILLISECONDS));
613 >
614 >                // untimed tryAcquire will barge and succeed
615 >                assertTrue(s.tryAcquire());
616 >                s.release(2);
617 >                assertTrue(s.tryAcquire(2));
618 >                s.release();
619 >
620 >                pleaseRelease.countDown();
621 >                // Will queue up behind t1, even though 1 permit is available
622 >                s.acquire();
623 >            }});
624 >
625 >        await(pleaseRelease);
626 >        waitForQueuedThread(s, t2);
627 >        s.release(2);
628 >        awaitTermination(t1);
629 >        assertTrue(t2.isAlive());
630 >        s.release();
631 >        awaitTermination(t2);
632      }
633  
634      /**
635       * toString indicates current number of permits
636       */
637 <    public void testToString() {
638 <        Semaphore s = new Semaphore(0);
639 <        String us = s.toString();
640 <        assertTrue(us.indexOf("Permits = 0") >= 0);
641 <        s.release();
910 <        String s1 = s.toString();
911 <        assertTrue(s1.indexOf("Permits = 1") >= 0);
637 >    public void testToString()      { testToString(false); }
638 >    public void testToString_fair() { testToString(true); }
639 >    public void testToString(boolean fair) {
640 >        PublicSemaphore s = new PublicSemaphore(0, fair);
641 >        assertTrue(s.toString().contains("Permits = 0"));
642          s.release();
643 <        String s2 = s.toString();
644 <        assertTrue(s2.indexOf("Permits = 2") >= 0);
643 >        assertTrue(s.toString().contains("Permits = 1"));
644 >        s.release(2);
645 >        assertTrue(s.toString().contains("Permits = 3"));
646 >        s.reducePermits(5);
647 >        assertTrue(s.toString().contains("Permits = -2"));
648      }
649  
650   }

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