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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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import static java.util.concurrent.TimeUnit.MILLISECONDS; |
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|
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import java.util.Collection; |
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import java.util.concurrent.CountDownLatch; |
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import java.util.concurrent.Semaphore; |
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import java.util.concurrent.ThreadLocalRandom; |
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|
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import junit.framework.AssertionFailedError; |
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import junit.framework.Test; |
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import junit.framework.TestSuite; |
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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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main(suite(), args); |
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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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/** |
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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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/** |
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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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/** |
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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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Thread.State parkedState() { return Thread.State.TIMED_WAITING; } |
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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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Thread.State parkedState() { return Thread.State.TIMED_WAITING; } |
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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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Thread.State parkedState() { return Thread.State.WAITING; } |
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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() { |
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Semaphore s0 = new Semaphore(0); |
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assertEquals(0, s0.availablePermits()); |
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Semaphore s1 = new Semaphore(-1); |
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assertEquals(-1, s1.availablePermits()); |
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Semaphore s2 = new Semaphore(-1); |
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assertEquals(-1, s2.availablePermits()); |
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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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* tryAcquire succeeds when sufficent permits, else fails |
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* Constructor without fairness argument behaves as nonfair |
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*/ |
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public void testTryAcquireInSameThread() { |
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Semaphore s = new Semaphore(2); |
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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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/** |
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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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/** |
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* Acquire and release of semaphore succeed if initially available |
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* timed tryAcquire times out |
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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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unexpectedException(); |
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public void testTryAcquire_timeout() { |
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final boolean fair = ThreadLocalRandom.current().nextBoolean(); |
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final Semaphore s = new Semaphore(0, fair); |
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final 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() { |
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final boolean fair = ThreadLocalRandom.current().nextBoolean(); |
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final Semaphore s = new Semaphore(2, fair); |
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final 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 java.util.concurrent.CyclicBarrier pleaseInterrupt |
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= new java.util.concurrent.CyclicBarrier(2); |
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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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assertFalse(Thread.interrupted()); |
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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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assertFalse(Thread.interrupted()); |
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|
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// Interrupt during acquire |
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await(pleaseInterrupt); |
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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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assertFalse(Thread.interrupted()); |
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|
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// Interrupt during acquire(N) |
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await(pleaseInterrupt); |
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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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assertFalse(Thread.interrupted()); |
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}}); |
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|
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for (int n = 2; n-->0; ) { |
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await(pleaseInterrupt); |
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assertThreadBlocks(t, acquirer.parkedState()); |
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t.interrupt(); |
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} |
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|
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awaitTermination(t); |
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} |
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|
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/** |
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* Uninterruptible acquire and release of semaphore succeed if |
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* initially available |
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* acquireUninterruptibly(), acquireUninterruptibly(N) are |
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* uninterruptible |
281 |
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*/ |
282 |
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public void testAcquireUninterruptiblyReleaseInSameThread() { |
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Semaphore s = new Semaphore(1); |
284 |
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try { |
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s.acquireUninterruptibly(); |
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s.release(); |
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s.acquireUninterruptibly(); |
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s.release(); |
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s.acquireUninterruptibly(); |
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s.release(); |
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s.acquireUninterruptibly(); |
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s.release(); |
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s.acquireUninterruptibly(); |
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s.release(); |
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assertEquals(1, s.availablePermits()); |
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} finally { |
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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); |
288 |
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final Semaphore pleaseInterrupt = new Semaphore(-1, fair); |
289 |
> |
|
290 |
> |
Thread t1 = newStartedThread(new CheckedRunnable() { |
291 |
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public void realRun() throws InterruptedException { |
292 |
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// Interrupt before acquire |
293 |
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pleaseInterrupt.release(); |
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Thread.currentThread().interrupt(); |
295 |
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acquirer.acquire(s); |
296 |
> |
assertTrue(Thread.interrupted()); |
297 |
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}}); |
298 |
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|
299 |
> |
Thread t2 = newStartedThread(new CheckedRunnable() { |
300 |
> |
public void realRun() throws InterruptedException { |
301 |
> |
// Interrupt during acquire |
302 |
> |
pleaseInterrupt.release(); |
303 |
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acquirer.acquire(s); |
304 |
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assertTrue(Thread.interrupted()); |
305 |
> |
}}); |
306 |
> |
|
307 |
> |
await(pleaseInterrupt); |
308 |
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waitForQueuedThread(s, t1); |
309 |
> |
waitForQueuedThread(s, t2); |
310 |
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t2.interrupt(); |
311 |
> |
|
312 |
> |
assertThreadBlocks(t1, Thread.State.WAITING); |
313 |
> |
assertThreadBlocks(t2, Thread.State.WAITING); |
314 |
> |
|
315 |
> |
s.release(2); |
316 |
> |
|
317 |
> |
awaitTermination(t1); |
318 |
> |
awaitTermination(t2); |
319 |
> |
} |
320 |
> |
|
321 |
> |
/** |
322 |
> |
* hasQueuedThreads reports whether there are waiting threads |
323 |
> |
*/ |
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() { 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() { 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() { 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); |
403 |
> |
assertEquals(10, s.availablePermits()); |
404 |
> |
assertEquals(10, s.drainPermits()); |
405 |
> |
assertEquals(0, s.availablePermits()); |
406 |
> |
assertEquals(0, s.drainPermits()); |
407 |
|
} |
408 |
|
|
409 |
|
/** |
410 |
< |
* Timed Acquire and release of semaphore succeed if |
91 |
< |
* initially available |
410 |
> |
* release(-N) throws IllegalArgumentException |
411 |
|
*/ |
412 |
< |
public void testTimedAcquireReleaseInSameThread() { |
413 |
< |
Semaphore s = new Semaphore(1); |
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 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
418 |
< |
s.release(); |
419 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
99 |
< |
s.release(); |
100 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
101 |
< |
s.release(); |
102 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
103 |
< |
s.release(); |
104 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
105 |
< |
s.release(); |
106 |
< |
assertEquals(1, s.availablePermits()); |
107 |
< |
} catch( InterruptedException e){ |
108 |
< |
unexpectedException(); |
109 |
< |
} |
417 |
> |
s.release(-1); |
418 |
> |
shouldThrow(); |
419 |
> |
} catch (IllegalArgumentException success) {} |
420 |
|
} |
421 |
|
|
422 |
|
/** |
423 |
< |
* A release in one thread enables an acquire in another thread |
423 |
> |
* reducePermits(-N) throws IllegalArgumentException |
424 |
|
*/ |
425 |
< |
public void testAcquireReleaseInDifferentThreads() { |
426 |
< |
final Semaphore s = new Semaphore(0); |
427 |
< |
Thread t = new Thread(new Runnable() { |
428 |
< |
public void run() { |
119 |
< |
try { |
120 |
< |
s.acquire(); |
121 |
< |
s.release(); |
122 |
< |
s.release(); |
123 |
< |
s.acquire(); |
124 |
< |
} catch(InterruptedException ie){ |
125 |
< |
threadUnexpectedException(); |
126 |
< |
} |
127 |
< |
} |
128 |
< |
}); |
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 |
< |
t.start(); |
431 |
< |
Thread.sleep(SHORT_DELAY_MS); |
432 |
< |
s.release(); |
433 |
< |
s.release(); |
430 |
> |
s.reducePermits(-1); |
431 |
> |
shouldThrow(); |
432 |
> |
} catch (IllegalArgumentException success) {} |
433 |
> |
} |
434 |
> |
|
435 |
> |
/** |
436 |
> |
* reducePermits reduces number of permits |
437 |
> |
*/ |
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 |
> |
* a reserialized semaphore has same number of permits and |
457 |
> |
* fairness, but no queued threads |
458 |
> |
*/ |
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(); |
465 |
|
s.acquire(); |
466 |
|
s.release(); |
467 |
< |
t.join(); |
468 |
< |
} catch( InterruptedException e){ |
469 |
< |
unexpectedException(); |
467 |
> |
|
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 |
< |
* A release in one thread enables an uninterruptible acquire in another thread |
502 |
> |
* tryAcquire(n) succeeds when sufficient permits, else fails |
503 |
|
*/ |
504 |
< |
public void testUninterruptibleAcquireReleaseInDifferentThreads() { |
505 |
< |
final Semaphore s = new Semaphore(0); |
506 |
< |
Thread t = new Thread(new Runnable() { |
507 |
< |
public void run() { |
508 |
< |
s.acquireUninterruptibly(); |
509 |
< |
s.release(); |
510 |
< |
s.release(); |
511 |
< |
s.acquireUninterruptibly(); |
512 |
< |
} |
513 |
< |
}); |
514 |
< |
try { |
515 |
< |
t.start(); |
158 |
< |
Thread.sleep(SHORT_DELAY_MS); |
159 |
< |
s.release(); |
160 |
< |
s.release(); |
161 |
< |
s.acquireUninterruptibly(); |
162 |
< |
s.acquireUninterruptibly(); |
163 |
< |
s.release(); |
164 |
< |
t.join(); |
165 |
< |
} catch( InterruptedException e){ |
166 |
< |
unexpectedException(); |
167 |
< |
} |
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 |
|
|
170 |
– |
|
518 |
|
/** |
519 |
< |
* A release in one thread enables a timed acquire in another thread |
519 |
> |
* acquire succeeds if permits available |
520 |
|
*/ |
521 |
< |
public void testTimedAcquireReleaseInDifferentThreads() { |
522 |
< |
final Semaphore s = new Semaphore(1); |
523 |
< |
Thread t = new Thread(new Runnable() { |
524 |
< |
public void run() { |
525 |
< |
try { |
526 |
< |
s.release(); |
527 |
< |
threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
528 |
< |
s.release(); |
529 |
< |
threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
530 |
< |
|
531 |
< |
} catch(InterruptedException ie){ |
532 |
< |
threadUnexpectedException(); |
533 |
< |
} |
534 |
< |
} |
535 |
< |
}); |
536 |
< |
try { |
537 |
< |
t.start(); |
538 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
539 |
< |
s.release(); |
540 |
< |
assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS)); |
541 |
< |
s.release(); |
542 |
< |
s.release(); |
543 |
< |
t.join(); |
544 |
< |
} catch( InterruptedException e){ |
545 |
< |
unexpectedException(); |
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()); |
547 |
|
} |
548 |
|
} |
549 |
|
|
550 |
|
/** |
551 |
< |
* A waiting acquire blocks interruptibly |
552 |
< |
*/ |
553 |
< |
public void testAcquire_InterruptedException() { |
554 |
< |
final Semaphore s = new Semaphore(0); |
555 |
< |
Thread t = new Thread(new Runnable() { |
556 |
< |
public void run() { |
557 |
< |
try { |
558 |
< |
s.acquire(); |
559 |
< |
threadShouldThrow(); |
560 |
< |
} catch(InterruptedException success){} |
561 |
< |
} |
562 |
< |
}); |
563 |
< |
t.start(); |
564 |
< |
try { |
565 |
< |
Thread.sleep(SHORT_DELAY_MS); |
566 |
< |
t.interrupt(); |
567 |
< |
t.join(); |
568 |
< |
} catch(InterruptedException e){ |
569 |
< |
unexpectedException(); |
570 |
< |
} |
571 |
< |
} |
572 |
< |
|
573 |
< |
/** |
574 |
< |
* A waiting timed acquire blocks interruptibly |
575 |
< |
*/ |
576 |
< |
public void testTryAcquire_InterruptedException() { |
577 |
< |
final Semaphore s = new Semaphore(0); |
578 |
< |
Thread t = new Thread(new Runnable() { |
579 |
< |
public void run() { |
580 |
< |
try { |
581 |
< |
s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS); |
582 |
< |
threadShouldThrow(); |
583 |
< |
} catch(InterruptedException success){ |
584 |
< |
} |
585 |
< |
} |
586 |
< |
}); |
587 |
< |
t.start(); |
240 |
< |
try { |
241 |
< |
Thread.sleep(SHORT_DELAY_MS); |
242 |
< |
t.interrupt(); |
243 |
< |
t.join(); |
244 |
< |
} catch(InterruptedException e){ |
245 |
< |
unexpectedException(); |
551 |
> |
* release in one thread enables acquire in another thread |
552 |
> |
*/ |
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 |
< |
* a deserialized serialized semaphore has same number of permits |
595 |
> |
* fair locks are strictly FIFO |
596 |
|
*/ |
597 |
< |
public void testSerialization() { |
598 |
< |
Semaphore l = new Semaphore(3); |
599 |
< |
try { |
600 |
< |
l.acquire(); |
601 |
< |
l.release(); |
602 |
< |
ByteArrayOutputStream bout = new ByteArrayOutputStream(10000); |
603 |
< |
ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout)); |
604 |
< |
out.writeObject(l); |
605 |
< |
out.close(); |
606 |
< |
|
607 |
< |
ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray()); |
608 |
< |
ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin)); |
609 |
< |
Semaphore r = (Semaphore) in.readObject(); |
610 |
< |
assertEquals(3, r.availablePermits()); |
611 |
< |
r.acquire(); |
612 |
< |
r.release(); |
613 |
< |
} catch(Exception e){ |
614 |
< |
unexpectedException(); |
615 |
< |
} |
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() { 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 |
> |
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 |
|
} |