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/* |
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* Written by members of JCP JSR-166 Expert Group and released to the |
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* public domain. Use, modify, and redistribute this code in any way |
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* without acknowledgement. Other contributors include Andrew Wright, |
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* Jeffrey Hayes, Pat Fischer, Mike Judd. |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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* Other contributors include Andrew Wright, Jeffrey Hayes, |
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* Pat Fisher, Mike Judd. |
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*/ |
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import junit.framework.*; |
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import java.util.*; |
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import java.util.concurrent.*; |
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import java.io.*; |
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|
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public class SemaphoreTest extends TestCase{ |
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import java.util.concurrent.CountDownLatch; |
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import java.util.concurrent.Semaphore; |
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import static java.util.concurrent.TimeUnit.MILLISECONDS; |
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|
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public class SemaphoreTest extends JSR166TestCase { |
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public static void main(String[] args) { |
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junit.textui.TestRunner.run (suite()); |
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junit.textui.TestRunner.run(suite()); |
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} |
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|
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public static Test suite() { |
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return new TestSuite(SemaphoreTest.class); |
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return new TestSuite(SemaphoreTest.class); |
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} |
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|
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private static long SHORT_DELAY_MS = 100; |
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private static long MEDIUM_DELAY_MS = 1000; |
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private static long LONG_DELAY_MS = 10000; |
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/** |
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* Subclass to expose protected methods |
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*/ |
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static class PublicSemaphore extends Semaphore { |
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PublicSemaphore(int permits) { super(permits); } |
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PublicSemaphore(int permits, boolean fair) { super(permits, fair); } |
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public Collection<Thread> getQueuedThreads() { |
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return super.getQueuedThreads(); |
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} |
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public boolean hasQueuedThread(Thread t) { |
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return super.getQueuedThreads().contains(t); |
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} |
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public void reducePermits(int reduction) { |
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super.reducePermits(reduction); |
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} |
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} |
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|
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/** |
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* A runnable calling acquire |
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*/ |
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class InterruptibleLockRunnable extends CheckedRunnable { |
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final Semaphore lock; |
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InterruptibleLockRunnable(Semaphore s) { lock = s; } |
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public void realRun() { |
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try { |
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lock.acquire(); |
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} |
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catch (InterruptedException ignored) {} |
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} |
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} |
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|
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public void testConstructor1() { |
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Semaphore s = new Semaphore(0); |
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assertEquals(0, s.availablePermits()); |
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/** |
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* A runnable calling acquire that expects to be interrupted |
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*/ |
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class InterruptedLockRunnable extends CheckedInterruptedRunnable { |
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final Semaphore lock; |
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InterruptedLockRunnable(Semaphore s) { lock = s; } |
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public void realRun() throws InterruptedException { |
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lock.acquire(); |
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} |
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} |
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|
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public void testConstructor2() { |
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Semaphore s = new Semaphore(-1); |
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assertEquals(-1, s.availablePermits()); |
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/** |
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* Spin-waits until s.hasQueuedThread(t) becomes true. |
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*/ |
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void waitForQueuedThread(PublicSemaphore s, Thread t) { |
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long startTime = System.nanoTime(); |
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while (!s.hasQueuedThread(t)) { |
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if (millisElapsedSince(startTime) > LONG_DELAY_MS) |
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throw new AssertionFailedError("timed out"); |
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Thread.yield(); |
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} |
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assertTrue(s.hasQueuedThreads()); |
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assertTrue(t.isAlive()); |
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} |
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|
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/** |
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* Spin-waits until s.hasQueuedThreads() becomes true. |
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*/ |
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void waitForQueuedThreads(Semaphore s) { |
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long startTime = System.nanoTime(); |
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while (!s.hasQueuedThreads()) { |
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if (millisElapsedSince(startTime) > LONG_DELAY_MS) |
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throw new AssertionFailedError("timed out"); |
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Thread.yield(); |
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} |
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} |
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|
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enum AcquireMethod { |
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acquire() { |
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void acquire(Semaphore s) throws InterruptedException { |
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s.acquire(); |
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} |
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}, |
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acquireN() { |
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void acquire(Semaphore s, int permits) throws InterruptedException { |
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s.acquire(permits); |
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} |
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}, |
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acquireUninterruptibly() { |
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void acquire(Semaphore s) { |
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s.acquireUninterruptibly(); |
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} |
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}, |
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acquireUninterruptiblyN() { |
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void acquire(Semaphore s, int permits) { |
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s.acquireUninterruptibly(permits); |
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} |
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}, |
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tryAcquire() { |
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void acquire(Semaphore s) { |
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assertTrue(s.tryAcquire()); |
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} |
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}, |
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tryAcquireN() { |
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void acquire(Semaphore s, int permits) { |
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assertTrue(s.tryAcquire(permits)); |
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} |
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}, |
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tryAcquireTimed() { |
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void acquire(Semaphore s) throws InterruptedException { |
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assertTrue(s.tryAcquire(2 * LONG_DELAY_MS, MILLISECONDS)); |
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} |
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}, |
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tryAcquireTimedN { |
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void acquire(Semaphore s, int permits) throws InterruptedException { |
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assertTrue(s.tryAcquire(permits, 2 * LONG_DELAY_MS, MILLISECONDS)); |
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} |
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}; |
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|
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// Intentionally meta-circular |
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|
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/** Acquires 1 permit. */ |
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void acquire(Semaphore s) throws InterruptedException { |
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acquire(s, 1); |
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} |
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/** Acquires the given number of permits. */ |
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void acquire(Semaphore s, int permits) throws InterruptedException { |
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for (int i = 0; i < permits; i++) |
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acquire(s); |
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} |
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} |
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|
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/** |
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* Zero, negative, and positive initial values are allowed in constructor |
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*/ |
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public void testConstructor() { testConstructor(false); } |
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public void testConstructor_fair() { testConstructor(true); } |
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public void testConstructor(boolean fair) { |
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for (int permits : new int[] { -42, -1, 0, 1, 42 }) { |
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Semaphore s = new Semaphore(permits, fair); |
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assertEquals(permits, s.availablePermits()); |
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assertEquals(fair, s.isFair()); |
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} |
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} |
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|
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/** |
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* Constructor without fairness argument behaves as nonfair |
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*/ |
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public void testConstructorDefaultsToNonFair() { |
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for (int permits : new int[] { -42, -1, 0, 1, 42 }) { |
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Semaphore s = new Semaphore(permits); |
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assertEquals(permits, s.availablePermits()); |
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assertFalse(s.isFair()); |
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} |
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} |
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|
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public void testTryAcquireInSameThread() { |
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Semaphore s = new Semaphore(2); |
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/** |
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* tryAcquire succeeds when sufficient permits, else fails |
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*/ |
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public void testTryAcquireInSameThread() { testTryAcquireInSameThread(false); } |
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public void testTryAcquireInSameThread_fair() { testTryAcquireInSameThread(true); } |
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public void testTryAcquireInSameThread(boolean fair) { |
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Semaphore s = new Semaphore(2, fair); |
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assertEquals(2, s.availablePermits()); |
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assertTrue(s.tryAcquire()); |
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assertTrue(s.tryAcquire()); |
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assertEquals(0, s.availablePermits()); |
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assertFalse(s.tryAcquire()); |
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assertFalse(s.tryAcquire()); |
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assertEquals(0, s.availablePermits()); |
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} |
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|
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public void testAcquireReleaseInSameThread(){ |
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Semaphore s = new Semaphore(1); |
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try { |
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s.acquire(); |
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s.release(); |
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s.acquire(); |
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s.release(); |
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s.acquire(); |
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s.release(); |
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s.acquire(); |
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s.release(); |
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s.acquire(); |
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s.release(); |
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assertEquals(1, s.availablePermits()); |
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} catch( InterruptedException e){ |
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fail("unexpected exception"); |
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} |
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/** |
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* timed tryAcquire times out |
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*/ |
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public void testTryAcquire_timeout() { testTryAcquire_timeout(false); } |
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public void testTryAcquire_timeout_fair() { testTryAcquire_timeout(true); } |
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public void testTryAcquire_timeout(boolean fair) { |
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Semaphore s = new Semaphore(0, fair); |
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long startTime = System.nanoTime(); |
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try { assertFalse(s.tryAcquire(timeoutMillis(), MILLISECONDS)); } |
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catch (InterruptedException e) { threadUnexpectedException(e); } |
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assertTrue(millisElapsedSince(startTime) >= timeoutMillis()); |
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} |
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|
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/** |
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* timed tryAcquire(N) times out |
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*/ |
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public void testTryAcquireN_timeout() { testTryAcquireN_timeout(false); } |
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public void testTryAcquireN_timeout_fair() { testTryAcquireN_timeout(true); } |
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public void testTryAcquireN_timeout(boolean fair) { |
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Semaphore s = new Semaphore(2, fair); |
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long startTime = System.nanoTime(); |
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try { assertFalse(s.tryAcquire(3, timeoutMillis(), MILLISECONDS)); } |
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catch (InterruptedException e) { threadUnexpectedException(e); } |
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assertTrue(millisElapsedSince(startTime) >= timeoutMillis()); |
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} |
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|
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/** |
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* acquire(), acquire(N), timed tryAcquired, timed tryAcquire(N) |
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* are interruptible |
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*/ |
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public void testInterruptible_acquire() { testInterruptible(false, AcquireMethod.acquire); } |
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public void testInterruptible_acquire_fair() { testInterruptible(true, AcquireMethod.acquire); } |
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public void testInterruptible_acquireN() { testInterruptible(false, AcquireMethod.acquireN); } |
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public void testInterruptible_acquireN_fair() { testInterruptible(true, AcquireMethod.acquireN); } |
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public void testInterruptible_tryAcquireTimed() { testInterruptible(false, AcquireMethod.tryAcquireTimed); } |
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public void testInterruptible_tryAcquireTimed_fair() { testInterruptible(true, AcquireMethod.tryAcquireTimed); } |
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public void testInterruptible_tryAcquireTimedN() { testInterruptible(false, AcquireMethod.tryAcquireTimedN); } |
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public void testInterruptible_tryAcquireTimedN_fair() { testInterruptible(true, AcquireMethod.tryAcquireTimedN); } |
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public void testInterruptible(boolean fair, final AcquireMethod acquirer) { |
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final PublicSemaphore s = new PublicSemaphore(0, fair); |
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final Semaphore pleaseInterrupt = new Semaphore(0, fair); |
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Thread t = newStartedThread(new CheckedRunnable() { |
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public void realRun() { |
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// Interrupt before acquire |
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Thread.currentThread().interrupt(); |
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try { |
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acquirer.acquire(s); |
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shouldThrow(); |
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} catch (InterruptedException success) {} |
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|
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// Interrupt during acquire |
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try { |
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acquirer.acquire(s); |
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shouldThrow(); |
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} catch (InterruptedException success) {} |
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|
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// Interrupt before acquire(N) |
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Thread.currentThread().interrupt(); |
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try { |
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acquirer.acquire(s, 3); |
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shouldThrow(); |
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} catch (InterruptedException success) {} |
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|
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pleaseInterrupt.release(); |
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|
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// Interrupt during acquire(N) |
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try { |
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acquirer.acquire(s, 3); |
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shouldThrow(); |
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} catch (InterruptedException success) {} |
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}}); |
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|
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waitForQueuedThread(s, t); |
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t.interrupt(); |
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await(pleaseInterrupt); |
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waitForQueuedThread(s, t); |
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t.interrupt(); |
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awaitTermination(t); |
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} |
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|
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/** |
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* acquireUninterruptibly(), acquireUninterruptibly(N) are |
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* uninterruptible |
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*/ |
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public void testUninterruptible_acquireUninterruptibly() { testUninterruptible(false, AcquireMethod.acquireUninterruptibly); } |
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public void testUninterruptible_acquireUninterruptibly_fair() { testUninterruptible(true, AcquireMethod.acquireUninterruptibly); } |
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public void testUninterruptible_acquireUninterruptiblyN() { testUninterruptible(false, AcquireMethod.acquireUninterruptiblyN); } |
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public void testUninterruptible_acquireUninterruptiblyN_fair() { testUninterruptible(true, AcquireMethod.acquireUninterruptiblyN); } |
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public void testUninterruptible(boolean fair, final AcquireMethod acquirer) { |
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final PublicSemaphore s = new PublicSemaphore(0, fair); |
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final Semaphore pleaseInterrupt = new Semaphore(-1, fair); |
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|
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Thread t1 = newStartedThread(new CheckedRunnable() { |
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public void realRun() throws InterruptedException { |
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// Interrupt before acquire |
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pleaseInterrupt.release(); |
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Thread.currentThread().interrupt(); |
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acquirer.acquire(s); |
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assertTrue(Thread.interrupted()); |
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}}); |
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|
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Thread t2 = newStartedThread(new CheckedRunnable() { |
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public void realRun() throws InterruptedException { |
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// Interrupt during acquire |
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pleaseInterrupt.release(); |
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acquirer.acquire(s); |
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assertTrue(Thread.interrupted()); |
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}}); |
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|
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await(pleaseInterrupt); |
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waitForQueuedThread(s, t1); |
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waitForQueuedThread(s, t2); |
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t2.interrupt(); |
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|
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assertThreadStaysAlive(t1); |
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assertTrue(t2.isAlive()); |
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|
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s.release(2); |
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|
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awaitTermination(t1); |
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awaitTermination(t2); |
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} |
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|
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/** |
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* hasQueuedThreads reports whether there are waiting threads |
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*/ |
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public void testHasQueuedThreads() { testHasQueuedThreads(false); } |
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public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); } |
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public void testHasQueuedThreads(boolean fair) { |
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final PublicSemaphore lock = new PublicSemaphore(1, fair); |
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assertFalse(lock.hasQueuedThreads()); |
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lock.acquireUninterruptibly(); |
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Thread t1 = newStartedThread(new InterruptedLockRunnable(lock)); |
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waitForQueuedThread(lock, t1); |
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assertTrue(lock.hasQueuedThreads()); |
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Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock)); |
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waitForQueuedThread(lock, t2); |
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assertTrue(lock.hasQueuedThreads()); |
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t1.interrupt(); |
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awaitTermination(t1); |
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assertTrue(lock.hasQueuedThreads()); |
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lock.release(); |
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awaitTermination(t2); |
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assertFalse(lock.hasQueuedThreads()); |
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} |
331 |
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|
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/** |
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* getQueueLength reports number of waiting threads |
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*/ |
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public void testGetQueueLength() { testGetQueueLength(false); } |
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public void testGetQueueLength_fair() { testGetQueueLength(true); } |
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public void testGetQueueLength(boolean fair) { |
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final PublicSemaphore lock = new PublicSemaphore(1, fair); |
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assertEquals(0, lock.getQueueLength()); |
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lock.acquireUninterruptibly(); |
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Thread t1 = newStartedThread(new InterruptedLockRunnable(lock)); |
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waitForQueuedThread(lock, t1); |
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assertEquals(1, lock.getQueueLength()); |
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Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock)); |
345 |
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waitForQueuedThread(lock, t2); |
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assertEquals(2, lock.getQueueLength()); |
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t1.interrupt(); |
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awaitTermination(t1); |
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assertEquals(1, lock.getQueueLength()); |
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lock.release(); |
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awaitTermination(t2); |
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assertEquals(0, lock.getQueueLength()); |
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} |
354 |
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|
355 |
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/** |
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* getQueuedThreads includes waiting threads |
357 |
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*/ |
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public void testGetQueuedThreads() { testGetQueuedThreads(false); } |
359 |
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public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); } |
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public void testGetQueuedThreads(boolean fair) { |
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final PublicSemaphore lock = new PublicSemaphore(1, fair); |
362 |
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assertTrue(lock.getQueuedThreads().isEmpty()); |
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lock.acquireUninterruptibly(); |
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> |
assertTrue(lock.getQueuedThreads().isEmpty()); |
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Thread t1 = newStartedThread(new InterruptedLockRunnable(lock)); |
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waitForQueuedThread(lock, t1); |
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assertTrue(lock.getQueuedThreads().contains(t1)); |
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Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock)); |
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waitForQueuedThread(lock, t2); |
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assertTrue(lock.getQueuedThreads().contains(t1)); |
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> |
assertTrue(lock.getQueuedThreads().contains(t2)); |
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t1.interrupt(); |
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awaitTermination(t1); |
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assertFalse(lock.getQueuedThreads().contains(t1)); |
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assertTrue(lock.getQueuedThreads().contains(t2)); |
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lock.release(); |
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awaitTermination(t2); |
378 |
> |
assertTrue(lock.getQueuedThreads().isEmpty()); |
379 |
> |
} |
380 |
> |
|
381 |
> |
/** |
382 |
> |
* drainPermits reports and removes given number of permits |
383 |
> |
*/ |
384 |
> |
public void testDrainPermits() { testDrainPermits(false); } |
385 |
> |
public void testDrainPermits_fair() { testDrainPermits(true); } |
386 |
> |
public void testDrainPermits(boolean fair) { |
387 |
> |
Semaphore s = new Semaphore(0, fair); |
388 |
> |
assertEquals(0, s.availablePermits()); |
389 |
> |
assertEquals(0, s.drainPermits()); |
390 |
> |
s.release(10); |
391 |
> |
assertEquals(10, s.availablePermits()); |
392 |
> |
assertEquals(10, s.drainPermits()); |
393 |
> |
assertEquals(0, s.availablePermits()); |
394 |
> |
assertEquals(0, s.drainPermits()); |
395 |
|
} |
396 |
|
|
397 |
< |
public void testAcquireUninterruptiblyReleaseInSameThread(){ |
398 |
< |
Semaphore s = new Semaphore(1); |
397 |
> |
/** |
398 |
> |
* release(-N) throws IllegalArgumentException |
399 |
> |
*/ |
400 |
> |
public void testReleaseIAE() { testReleaseIAE(false); } |
401 |
> |
public void testReleaseIAE_fair() { testReleaseIAE(true); } |
402 |
> |
public void testReleaseIAE(boolean fair) { |
403 |
> |
Semaphore s = new Semaphore(10, fair); |
404 |
|
try { |
405 |
< |
s.acquireUninterruptibly(); |
406 |
< |
s.release(); |
407 |
< |
s.acquireUninterruptibly(); |
72 |
< |
s.release(); |
73 |
< |
s.acquireUninterruptibly(); |
74 |
< |
s.release(); |
75 |
< |
s.acquireUninterruptibly(); |
76 |
< |
s.release(); |
77 |
< |
s.acquireUninterruptibly(); |
78 |
< |
s.release(); |
79 |
< |
assertEquals(1, s.availablePermits()); |
80 |
< |
} finally { |
81 |
< |
} |
405 |
> |
s.release(-1); |
406 |
> |
shouldThrow(); |
407 |
> |
} catch (IllegalArgumentException success) {} |
408 |
|
} |
409 |
|
|
410 |
< |
|
411 |
< |
public void testAcquireReleaseInDifferentThreads() { |
412 |
< |
final Semaphore s = new Semaphore(1); |
413 |
< |
Thread t = new Thread(new Runnable(){ |
414 |
< |
public void run(){ |
415 |
< |
try{ |
416 |
< |
s.acquire(); |
91 |
< |
s.release(); |
92 |
< |
s.release(); |
93 |
< |
s.acquire(); |
94 |
< |
}catch(InterruptedException ie){ |
95 |
< |
fail("unexpected exception"); |
96 |
< |
} |
97 |
< |
} |
98 |
< |
}); |
99 |
< |
t.start(); |
410 |
> |
/** |
411 |
> |
* reducePermits(-N) throws IllegalArgumentException |
412 |
> |
*/ |
413 |
> |
public void testReducePermitsIAE() { testReducePermitsIAE(false); } |
414 |
> |
public void testReducePermitsIAE_fair() { testReducePermitsIAE(true); } |
415 |
> |
public void testReducePermitsIAE(boolean fair) { |
416 |
> |
PublicSemaphore s = new PublicSemaphore(10, fair); |
417 |
|
try { |
418 |
< |
s.release(); |
419 |
< |
s.release(); |
420 |
< |
s.acquire(); |
421 |
< |
s.acquire(); |
422 |
< |
t.join(); |
423 |
< |
} catch( InterruptedException e){ |
424 |
< |
fail("unexpected exception"); |
425 |
< |
} |
418 |
> |
s.reducePermits(-1); |
419 |
> |
shouldThrow(); |
420 |
> |
} catch (IllegalArgumentException success) {} |
421 |
> |
} |
422 |
> |
|
423 |
> |
/** |
424 |
> |
* reducePermits reduces number of permits |
425 |
> |
*/ |
426 |
> |
public void testReducePermits() { testReducePermits(false); } |
427 |
> |
public void testReducePermits_fair() { testReducePermits(true); } |
428 |
> |
public void testReducePermits(boolean fair) { |
429 |
> |
PublicSemaphore s = new PublicSemaphore(10, fair); |
430 |
> |
assertEquals(10, s.availablePermits()); |
431 |
> |
s.reducePermits(0); |
432 |
> |
assertEquals(10, s.availablePermits()); |
433 |
> |
s.reducePermits(1); |
434 |
> |
assertEquals(9, s.availablePermits()); |
435 |
> |
s.reducePermits(10); |
436 |
> |
assertEquals(-1, s.availablePermits()); |
437 |
> |
s.reducePermits(10); |
438 |
> |
assertEquals(-11, s.availablePermits()); |
439 |
> |
s.reducePermits(0); |
440 |
> |
assertEquals(-11, s.availablePermits()); |
441 |
|
} |
442 |
|
|
443 |
< |
public void testTimedAcquireReleaseInSameThread(){ |
444 |
< |
Semaphore s = new Semaphore(1); |
443 |
> |
/** |
444 |
> |
* a reserialized semaphore has same number of permits and |
445 |
> |
* fairness, but no queued threads |
446 |
> |
*/ |
447 |
> |
public void testSerialization() { testSerialization(false); } |
448 |
> |
public void testSerialization_fair() { testSerialization(true); } |
449 |
> |
public void testSerialization(boolean fair) { |
450 |
|
try { |
451 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
452 |
< |
s.release(); |
453 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
117 |
< |
s.release(); |
118 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
119 |
< |
s.release(); |
120 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
121 |
< |
s.release(); |
122 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
451 |
> |
Semaphore s = new Semaphore(3, fair); |
452 |
> |
s.acquire(); |
453 |
> |
s.acquire(); |
454 |
|
s.release(); |
455 |
< |
assertEquals(1, s.availablePermits()); |
456 |
< |
} catch( InterruptedException e){ |
457 |
< |
fail("unexpected exception"); |
458 |
< |
} |
455 |
> |
|
456 |
> |
Semaphore clone = serialClone(s); |
457 |
> |
assertEquals(fair, s.isFair()); |
458 |
> |
assertEquals(fair, clone.isFair()); |
459 |
> |
assertEquals(2, s.availablePermits()); |
460 |
> |
assertEquals(2, clone.availablePermits()); |
461 |
> |
clone.acquire(); |
462 |
> |
clone.acquire(); |
463 |
> |
clone.release(); |
464 |
> |
assertEquals(2, s.availablePermits()); |
465 |
> |
assertEquals(1, clone.availablePermits()); |
466 |
> |
|
467 |
> |
s = new Semaphore(0, fair); |
468 |
> |
Thread t = newStartedThread(new InterruptibleLockRunnable(s)); |
469 |
> |
waitForQueuedThreads(s); |
470 |
> |
clone = serialClone(s); |
471 |
> |
assertEquals(fair, s.isFair()); |
472 |
> |
assertEquals(fair, clone.isFair()); |
473 |
> |
assertEquals(0, s.availablePermits()); |
474 |
> |
assertEquals(0, clone.availablePermits()); |
475 |
> |
assertTrue(s.hasQueuedThreads()); |
476 |
> |
assertFalse(clone.hasQueuedThreads()); |
477 |
> |
s.release(); |
478 |
> |
awaitTermination(t); |
479 |
> |
assertFalse(s.hasQueuedThreads()); |
480 |
> |
assertFalse(clone.hasQueuedThreads()); |
481 |
> |
} catch (InterruptedException e) { threadUnexpectedException(e); } |
482 |
> |
} |
483 |
> |
|
484 |
> |
/** |
485 |
> |
* tryAcquire(n) succeeds when sufficient permits, else fails |
486 |
> |
*/ |
487 |
> |
public void testTryAcquireNInSameThread() { testTryAcquireNInSameThread(false); } |
488 |
> |
public void testTryAcquireNInSameThread_fair() { testTryAcquireNInSameThread(true); } |
489 |
> |
public void testTryAcquireNInSameThread(boolean fair) { |
490 |
> |
Semaphore s = new Semaphore(2, fair); |
491 |
> |
assertEquals(2, s.availablePermits()); |
492 |
> |
assertFalse(s.tryAcquire(3)); |
493 |
> |
assertEquals(2, s.availablePermits()); |
494 |
> |
assertTrue(s.tryAcquire(2)); |
495 |
> |
assertEquals(0, s.availablePermits()); |
496 |
> |
assertFalse(s.tryAcquire(1)); |
497 |
> |
assertFalse(s.tryAcquire(2)); |
498 |
> |
assertEquals(0, s.availablePermits()); |
499 |
|
} |
500 |
|
|
501 |
< |
public void testTimedAcquireReleaseInDifferentThreads() { |
502 |
< |
final Semaphore s = new Semaphore(1); |
503 |
< |
Thread t = new Thread(new Runnable(){ |
504 |
< |
public void run(){ |
505 |
< |
try{ |
506 |
< |
s.release(); |
507 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
508 |
< |
s.release(); |
509 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
510 |
< |
|
511 |
< |
}catch(InterruptedException ie){ |
512 |
< |
fail("unexpected exception"); |
513 |
< |
} |
514 |
< |
} |
515 |
< |
}); |
516 |
< |
t.start(); |
517 |
< |
try { |
518 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
519 |
< |
s.release(); |
520 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
521 |
< |
s.release(); |
522 |
< |
t.join(); |
523 |
< |
} catch( InterruptedException e){ |
524 |
< |
fail("unexpected exception"); |
501 |
> |
/** |
502 |
> |
* acquire succeeds if permits available |
503 |
> |
*/ |
504 |
> |
public void testReleaseAcquireSameThread_acquire() { testReleaseAcquireSameThread(false, AcquireMethod.acquire); } |
505 |
> |
public void testReleaseAcquireSameThread_acquire_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquire); } |
506 |
> |
public void testReleaseAcquireSameThread_acquireN() { testReleaseAcquireSameThread(false, AcquireMethod.acquireN); } |
507 |
> |
public void testReleaseAcquireSameThread_acquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireN); } |
508 |
> |
public void testReleaseAcquireSameThread_acquireUninterruptibly() { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); } |
509 |
> |
public void testReleaseAcquireSameThread_acquireUninterruptibly_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); } |
510 |
> |
public void testReleaseAcquireSameThread_acquireUninterruptiblyN() { testReleaseAcquireSameThread(false, AcquireMethod.acquireUninterruptibly); } |
511 |
> |
public void testReleaseAcquireSameThread_acquireUninterruptiblyN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.acquireUninterruptibly); } |
512 |
> |
public void testReleaseAcquireSameThread_tryAcquire() { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquire); } |
513 |
> |
public void testReleaseAcquireSameThread_tryAcquire_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquire); } |
514 |
> |
public void testReleaseAcquireSameThread_tryAcquireN() { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireN); } |
515 |
> |
public void testReleaseAcquireSameThread_tryAcquireN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireN); } |
516 |
> |
public void testReleaseAcquireSameThread_tryAcquireTimed() { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimed); } |
517 |
> |
public void testReleaseAcquireSameThread_tryAcquireTimed_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimed); } |
518 |
> |
public void testReleaseAcquireSameThread_tryAcquireTimedN() { testReleaseAcquireSameThread(false, AcquireMethod.tryAcquireTimedN); } |
519 |
> |
public void testReleaseAcquireSameThread_tryAcquireTimedN_fair() { testReleaseAcquireSameThread(true, AcquireMethod.tryAcquireTimedN); } |
520 |
> |
public void testReleaseAcquireSameThread(boolean fair, |
521 |
> |
final AcquireMethod acquirer) { |
522 |
> |
Semaphore s = new Semaphore(1, fair); |
523 |
> |
for (int i = 1; i < 6; i++) { |
524 |
> |
s.release(i); |
525 |
> |
assertEquals(1 + i, s.availablePermits()); |
526 |
> |
try { |
527 |
> |
acquirer.acquire(s, i); |
528 |
> |
} catch (InterruptedException e) { threadUnexpectedException(e); } |
529 |
> |
assertEquals(1, s.availablePermits()); |
530 |
|
} |
531 |
|
} |
532 |
|
|
533 |
< |
public void testAcquire_InterruptedException(){ |
534 |
< |
final Semaphore s = new Semaphore(0); |
535 |
< |
Thread t = new Thread(new Runnable(){ |
536 |
< |
public void run(){ |
537 |
< |
try{ |
538 |
< |
s.acquire(); |
539 |
< |
fail("should throw"); |
540 |
< |
}catch(InterruptedException success){} |
541 |
< |
} |
542 |
< |
}); |
543 |
< |
t.start(); |
544 |
< |
try{ |
545 |
< |
Thread.sleep(SHORT_DELAY_MS); |
546 |
< |
t.interrupt(); |
547 |
< |
t.join(); |
548 |
< |
} catch(InterruptedException e){ |
549 |
< |
fail("unexpected exception"); |
550 |
< |
} |
551 |
< |
} |
552 |
< |
|
553 |
< |
public void testTryAcquire_InterruptedException(){ |
554 |
< |
final Semaphore s = new Semaphore(0); |
555 |
< |
Thread t = new Thread(new Runnable(){ |
556 |
< |
public void run(){ |
557 |
< |
try{ |
558 |
< |
s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS); |
559 |
< |
fail("should throw"); |
560 |
< |
}catch(InterruptedException success){ |
561 |
< |
} |
562 |
< |
} |
563 |
< |
}); |
564 |
< |
t.start(); |
565 |
< |
try{ |
566 |
< |
Thread.sleep(SHORT_DELAY_MS); |
567 |
< |
t.interrupt(); |
568 |
< |
t.join(); |
569 |
< |
} catch(InterruptedException e){ |
570 |
< |
fail("unexpected exception"); |
533 |
> |
/** |
534 |
> |
* release in one thread enables acquire in another thread |
535 |
> |
*/ |
536 |
> |
public void testReleaseAcquireDifferentThreads_acquire() { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquire); } |
537 |
> |
public void testReleaseAcquireDifferentThreads_acquire_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquire); } |
538 |
> |
public void testReleaseAcquireDifferentThreads_acquireN() { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireN); } |
539 |
> |
public void testReleaseAcquireDifferentThreads_acquireN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireN); } |
540 |
> |
public void testReleaseAcquireDifferentThreads_acquireUninterruptibly() { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); } |
541 |
> |
public void testReleaseAcquireDifferentThreads_acquireUninterruptibly_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); } |
542 |
> |
public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN() { testReleaseAcquireDifferentThreads(false, AcquireMethod.acquireUninterruptibly); } |
543 |
> |
public void testReleaseAcquireDifferentThreads_acquireUninterruptiblyN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.acquireUninterruptibly); } |
544 |
> |
public void testReleaseAcquireDifferentThreads_tryAcquireTimed() { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimed); } |
545 |
> |
public void testReleaseAcquireDifferentThreads_tryAcquireTimed_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimed); } |
546 |
> |
public void testReleaseAcquireDifferentThreads_tryAcquireTimedN() { testReleaseAcquireDifferentThreads(false, AcquireMethod.tryAcquireTimedN); } |
547 |
> |
public void testReleaseAcquireDifferentThreads_tryAcquireTimedN_fair() { testReleaseAcquireDifferentThreads(true, AcquireMethod.tryAcquireTimedN); } |
548 |
> |
public void testReleaseAcquireDifferentThreads(boolean fair, |
549 |
> |
final AcquireMethod acquirer) { |
550 |
> |
final Semaphore s = new Semaphore(0, fair); |
551 |
> |
final int rounds = 4; |
552 |
> |
long startTime = System.nanoTime(); |
553 |
> |
Thread t = newStartedThread(new CheckedRunnable() { |
554 |
> |
public void realRun() throws InterruptedException { |
555 |
> |
for (int i = 0; i < rounds; i++) { |
556 |
> |
assertFalse(s.hasQueuedThreads()); |
557 |
> |
if (i % 2 == 0) |
558 |
> |
acquirer.acquire(s); |
559 |
> |
else |
560 |
> |
acquirer.acquire(s, 3); |
561 |
> |
}}}); |
562 |
> |
|
563 |
> |
for (int i = 0; i < rounds; i++) { |
564 |
> |
while (! (s.availablePermits() == 0 && s.hasQueuedThreads())) |
565 |
> |
Thread.yield(); |
566 |
> |
assertTrue(t.isAlive()); |
567 |
> |
if (i % 2 == 0) |
568 |
> |
s.release(); |
569 |
> |
else |
570 |
> |
s.release(3); |
571 |
|
} |
572 |
+ |
awaitTermination(t); |
573 |
+ |
assertEquals(0, s.availablePermits()); |
574 |
+ |
assertTrue(millisElapsedSince(startTime) < LONG_DELAY_MS); |
575 |
|
} |
576 |
|
|
577 |
< |
public void testSerialization() { |
578 |
< |
Semaphore l = new Semaphore(3); |
579 |
< |
|
580 |
< |
try { |
581 |
< |
l.acquire(); |
582 |
< |
l.release(); |
583 |
< |
ByteArrayOutputStream bout = new ByteArrayOutputStream(10000); |
584 |
< |
ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout)); |
585 |
< |
out.writeObject(l); |
586 |
< |
out.close(); |
587 |
< |
|
588 |
< |
ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray()); |
589 |
< |
ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin)); |
590 |
< |
Semaphore r = (Semaphore) in.readObject(); |
591 |
< |
assertEquals(3, r.availablePermits()); |
592 |
< |
r.acquire(); |
593 |
< |
r.release(); |
594 |
< |
} catch(Exception e){ |
595 |
< |
e.printStackTrace(); |
596 |
< |
fail("unexpected exception"); |
597 |
< |
} |
577 |
> |
/** |
578 |
> |
* fair locks are strictly FIFO |
579 |
> |
*/ |
580 |
> |
public void testFairLocksFifo() { |
581 |
> |
final PublicSemaphore s = new PublicSemaphore(1, true); |
582 |
> |
final CountDownLatch pleaseRelease = new CountDownLatch(1); |
583 |
> |
Thread t1 = newStartedThread(new CheckedRunnable() { |
584 |
> |
public void realRun() throws InterruptedException { |
585 |
> |
// Will block; permits are available, but not three |
586 |
> |
s.acquire(3); |
587 |
> |
}}); |
588 |
> |
|
589 |
> |
waitForQueuedThreads(s); |
590 |
> |
|
591 |
> |
Thread t2 = newStartedThread(new CheckedRunnable() { |
592 |
> |
public void realRun() throws InterruptedException { |
593 |
> |
// Will fail, even though 1 permit is available |
594 |
> |
assertFalse(s.tryAcquire(0L, MILLISECONDS)); |
595 |
> |
assertFalse(s.tryAcquire(1, 0L, MILLISECONDS)); |
596 |
> |
|
597 |
> |
// untimed tryAcquire will barge and succeed |
598 |
> |
assertTrue(s.tryAcquire()); |
599 |
> |
s.release(2); |
600 |
> |
assertTrue(s.tryAcquire(2)); |
601 |
> |
s.release(); |
602 |
> |
|
603 |
> |
pleaseRelease.countDown(); |
604 |
> |
// Will queue up behind t1, even though 1 permit is available |
605 |
> |
s.acquire(); |
606 |
> |
}}); |
607 |
> |
|
608 |
> |
await(pleaseRelease); |
609 |
> |
waitForQueuedThread(s, t2); |
610 |
> |
s.release(2); |
611 |
> |
awaitTermination(t1); |
612 |
> |
assertTrue(t2.isAlive()); |
613 |
> |
s.release(); |
614 |
> |
awaitTermination(t2); |
615 |
> |
} |
616 |
> |
|
617 |
> |
/** |
618 |
> |
* toString indicates current number of permits |
619 |
> |
*/ |
620 |
> |
public void testToString() { testToString(false); } |
621 |
> |
public void testToString_fair() { testToString(true); } |
622 |
> |
public void testToString(boolean fair) { |
623 |
> |
PublicSemaphore s = new PublicSemaphore(0, fair); |
624 |
> |
assertTrue(s.toString().contains("Permits = 0")); |
625 |
> |
s.release(); |
626 |
> |
assertTrue(s.toString().contains("Permits = 1")); |
627 |
> |
s.release(2); |
628 |
> |
assertTrue(s.toString().contains("Permits = 3")); |
629 |
> |
s.reducePermits(5); |
630 |
> |
assertTrue(s.toString().contains("Permits = -2")); |
631 |
|
} |
632 |
|
|
633 |
|
} |