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/* |
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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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|
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import junit.framework.*; |
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import java.util.*; |
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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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} |
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public static Test suite() { |
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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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}, |
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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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/** |
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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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* 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(); |
231 |
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 |
237 |
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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|
258 |
waitForQueuedThread(s, t); |
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t.interrupt(); |
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await(pleaseInterrupt); |
261 |
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 |
281 |
pleaseInterrupt.release(); |
282 |
Thread.currentThread().interrupt(); |
283 |
acquirer.acquire(s); |
284 |
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); |
297 |
waitForQueuedThread(s, t2); |
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t2.interrupt(); |
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|
300 |
assertThreadStaysAlive(t1); |
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assertTrue(t2.isAlive()); |
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|
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s.release(2); |
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|
305 |
awaitTermination(t1); |
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awaitTermination(t2); |
307 |
} |
308 |
|
309 |
/** |
310 |
* hasQueuedThreads reports whether there are waiting threads |
311 |
*/ |
312 |
public void testHasQueuedThreads() { testHasQueuedThreads(false); } |
313 |
public void testHasQueuedThreads_fair() { testHasQueuedThreads(true); } |
314 |
public void testHasQueuedThreads(boolean fair) { |
315 |
final PublicSemaphore lock = new PublicSemaphore(1, fair); |
316 |
assertFalse(lock.hasQueuedThreads()); |
317 |
lock.acquireUninterruptibly(); |
318 |
Thread t1 = newStartedThread(new InterruptedLockRunnable(lock)); |
319 |
waitForQueuedThread(lock, t1); |
320 |
assertTrue(lock.hasQueuedThreads()); |
321 |
Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock)); |
322 |
waitForQueuedThread(lock, t2); |
323 |
assertTrue(lock.hasQueuedThreads()); |
324 |
t1.interrupt(); |
325 |
awaitTermination(t1); |
326 |
assertTrue(lock.hasQueuedThreads()); |
327 |
lock.release(); |
328 |
awaitTermination(t2); |
329 |
assertFalse(lock.hasQueuedThreads()); |
330 |
} |
331 |
|
332 |
/** |
333 |
* getQueueLength reports number of waiting threads |
334 |
*/ |
335 |
public void testGetQueueLength() { testGetQueueLength(false); } |
336 |
public void testGetQueueLength_fair() { testGetQueueLength(true); } |
337 |
public void testGetQueueLength(boolean fair) { |
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final PublicSemaphore lock = new PublicSemaphore(1, fair); |
339 |
assertEquals(0, lock.getQueueLength()); |
340 |
lock.acquireUninterruptibly(); |
341 |
Thread t1 = newStartedThread(new InterruptedLockRunnable(lock)); |
342 |
waitForQueuedThread(lock, t1); |
343 |
assertEquals(1, lock.getQueueLength()); |
344 |
Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock)); |
345 |
waitForQueuedThread(lock, t2); |
346 |
assertEquals(2, lock.getQueueLength()); |
347 |
t1.interrupt(); |
348 |
awaitTermination(t1); |
349 |
assertEquals(1, lock.getQueueLength()); |
350 |
lock.release(); |
351 |
awaitTermination(t2); |
352 |
assertEquals(0, lock.getQueueLength()); |
353 |
} |
354 |
|
355 |
/** |
356 |
* getQueuedThreads includes waiting threads |
357 |
*/ |
358 |
public void testGetQueuedThreads() { testGetQueuedThreads(false); } |
359 |
public void testGetQueuedThreads_fair() { testGetQueuedThreads(true); } |
360 |
public void testGetQueuedThreads(boolean fair) { |
361 |
final PublicSemaphore lock = new PublicSemaphore(1, fair); |
362 |
assertTrue(lock.getQueuedThreads().isEmpty()); |
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lock.acquireUninterruptibly(); |
364 |
assertTrue(lock.getQueuedThreads().isEmpty()); |
365 |
Thread t1 = newStartedThread(new InterruptedLockRunnable(lock)); |
366 |
waitForQueuedThread(lock, t1); |
367 |
assertTrue(lock.getQueuedThreads().contains(t1)); |
368 |
Thread t2 = newStartedThread(new InterruptibleLockRunnable(lock)); |
369 |
waitForQueuedThread(lock, t2); |
370 |
assertTrue(lock.getQueuedThreads().contains(t1)); |
371 |
assertTrue(lock.getQueuedThreads().contains(t2)); |
372 |
t1.interrupt(); |
373 |
awaitTermination(t1); |
374 |
assertFalse(lock.getQueuedThreads().contains(t1)); |
375 |
assertTrue(lock.getQueuedThreads().contains(t2)); |
376 |
lock.release(); |
377 |
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 |
/** |
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.release(-1); |
406 |
shouldThrow(); |
407 |
} catch (IllegalArgumentException success) {} |
408 |
} |
409 |
|
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.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 |
/** |
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 |
Semaphore s = new Semaphore(3, fair); |
452 |
s.acquire(); |
453 |
s.acquire(); |
454 |
s.release(); |
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 |
/** |
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 |
/** |
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 |
/** |
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 |
} |