semaphoretest.java

来自「SRI international 发布的OAA框架软件」· Java 代码 · 共 927 行 · 第 1/3 页

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/licenses/publicdomain
 * Other contributors include Andrew Wright, Jeffrey Hayes,
 * Pat Fisher, Mike Judd.
 */

import junit.framework.*;
import edu.emory.mathcs.backport.java.util.*;
import edu.emory.mathcs.backport.java.util.concurrent.*;
import java.io.*;
import java.util.*;

public class SemaphoreTest extends JSR166TestCase {
    public static void main(String[] args) {
        junit.textui.TestRunner.run (suite());
    }
    public static Test suite() {
        return new TestSuite(SemaphoreTest.class);
    }

    /**
     * Subclass to expose protected methods
     */
    static class PublicSemaphore extends Semaphore {
        PublicSemaphore(int p, boolean f) { super(p, f); }
        public Collection getQueuedThreads() {
            return super.getQueuedThreads();
        }
        public void reducePermits(int p) {
            super.reducePermits(p);
        }
    }

    /**
     * A runnable calling acquire
     */
    class InterruptibleLockRunnable implements Runnable {
        final Semaphore lock;
        InterruptibleLockRunnable(Semaphore l) { lock = l; }
        public void run() {
            try {
                lock.acquire();
            } catch(InterruptedException success){}
        }
    }


    /**
     * A runnable calling acquire that expects to be
     * interrupted
     */
    class InterruptedLockRunnable implements Runnable {
        final Semaphore lock;
        InterruptedLockRunnable(Semaphore l) { lock = l; }
        public void run() {
            try {
                lock.acquire();
                threadShouldThrow();
            } catch(InterruptedException success){}
        }
    }

    /**
     * Zero, negative, and positive initial values are allowed in constructor
     */
    public void testConstructor() {
        Semaphore s0 = new Semaphore(0, false);
        assertEquals(0, s0.availablePermits());
        assertFalse(s0.isFair());
        Semaphore s1 = new Semaphore(-1, false);
        assertEquals(-1, s1.availablePermits());
        assertFalse(s1.isFair());
        Semaphore s2 = new Semaphore(-1, false);
        assertEquals(-1, s2.availablePermits());
        assertFalse(s2.isFair());
    }

    /**
     * Constructor without fairness argument behaves as nonfair
     */
    public void testConstructor2() {
        Semaphore s0 = new Semaphore(0);
        assertEquals(0, s0.availablePermits());
        assertFalse(s0.isFair());
        Semaphore s1 = new Semaphore(-1);
        assertEquals(-1, s1.availablePermits());
        assertFalse(s1.isFair());
        Semaphore s2 = new Semaphore(-1);
        assertEquals(-1, s2.availablePermits());
        assertFalse(s2.isFair());
    }

    /**
     * tryAcquire succeeds when sufficient permits, else fails
     */
    public void testTryAcquireInSameThread() {
        Semaphore s = new Semaphore(2, false);
        assertEquals(2, s.availablePermits());
        assertTrue(s.tryAcquire());
        assertTrue(s.tryAcquire());
        assertEquals(0, s.availablePermits());
        assertFalse(s.tryAcquire());
    }

    /**
     * Acquire and release of semaphore succeed if initially available
     */
    public void testAcquireReleaseInSameThread() {
        Semaphore s = new Semaphore(1, false);
        try {
            s.acquire();
            s.release();
            s.acquire();
            s.release();
            s.acquire();
            s.release();
            s.acquire();
            s.release();
            s.acquire();
            s.release();
            assertEquals(1, s.availablePermits());
        } catch( InterruptedException e){
            unexpectedException();
        }
    }

    /**
     * Uninterruptible acquire and release of semaphore succeed if
     * initially available
     */
    public void testAcquireUninterruptiblyReleaseInSameThread() {
        Semaphore s = new Semaphore(1, false);
        try {
            s.acquireUninterruptibly();
            s.release();
            s.acquireUninterruptibly();
            s.release();
            s.acquireUninterruptibly();
            s.release();
            s.acquireUninterruptibly();
            s.release();
            s.acquireUninterruptibly();
            s.release();
            assertEquals(1, s.availablePermits());
        } finally {
        }
    }

    /**
     * Timed Acquire and release of semaphore succeed if
     * initially available
     */
    public void testTimedAcquireReleaseInSameThread() {
        Semaphore s = new Semaphore(1, false);
        try {
            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
            s.release();
            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
            s.release();
            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
            s.release();
            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
            s.release();
            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
            s.release();
            assertEquals(1, s.availablePermits());
        } catch( InterruptedException e){
            unexpectedException();
        }
    }

    /**
     * A release in one thread enables an acquire in another thread
     */
    public void testAcquireReleaseInDifferentThreads() {
        final Semaphore s = new Semaphore(0, false);
        Thread t = new Thread(new Runnable() {
                public void run() {
                    try {
                        s.acquire();
                        s.release();
                        s.release();
                        s.acquire();
                    } catch(InterruptedException ie){
                        threadUnexpectedException();
                    }
                }
            });
        try {
            t.start();
            Thread.sleep(SHORT_DELAY_MS);
            s.release();
            s.release();
            s.acquire();
            s.acquire();
            s.release();
            t.join();
        } catch( InterruptedException e){
            unexpectedException();
        }
    }

    /**
     * A release in one thread enables an uninterruptible acquire in another thread
     */
    public void testUninterruptibleAcquireReleaseInDifferentThreads() {
        final Semaphore s = new Semaphore(0, false);
        Thread t = new Thread(new Runnable() {
                public void run() {
                    s.acquireUninterruptibly();
                    s.release();
                    s.release();
                    s.acquireUninterruptibly();
                }
            });
        try {
            t.start();
            Thread.sleep(SHORT_DELAY_MS);
            s.release();
            s.release();
            s.acquireUninterruptibly();
            s.acquireUninterruptibly();
            s.release();
            t.join();
        } catch( InterruptedException e){
            unexpectedException();
        }
    }


    /**
     *  A release in one thread enables a timed acquire in another thread
     */
    public void testTimedAcquireReleaseInDifferentThreads() {
        final Semaphore s = new Semaphore(1, false);
        Thread t = new Thread(new Runnable() {
                public void run() {
                    try {
                        s.release();
                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
                        s.release();
                        threadAssertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));

                    } catch(InterruptedException ie){
                        threadUnexpectedException();
                    }
                }
            });
        try {
            t.start();
            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
            s.release();
            assertTrue(s.tryAcquire(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
            s.release();
            s.release();
            t.join();
        } catch( InterruptedException e){
            unexpectedException();
        }
    }

    /**
     * A waiting acquire blocks interruptibly
     */
    public void testAcquire_InterruptedException() {
        final Semaphore s = new Semaphore(0, false);
        Thread t = new Thread(new Runnable() {
                public void run() {
                    try {
                        s.acquire();
                        threadShouldThrow();
                    } catch(InterruptedException success){}
                }
            });
        t.start();
        try {
            Thread.sleep(SHORT_DELAY_MS);
            t.interrupt();
            t.join();
        } catch(InterruptedException e){
            unexpectedException();
        }
    }

    /**
     *  A waiting timed acquire blocks interruptibly
     */
    public void testTryAcquire_InterruptedException() {
        final Semaphore s = new Semaphore(0, false);
        Thread t = new Thread(new Runnable() {
                public void run() {
                    try {
                        s.tryAcquire(MEDIUM_DELAY_MS, TimeUnit.MILLISECONDS);
                        threadShouldThrow();
                    } catch(InterruptedException success){
                    }
                }
            });
        t.start();
        try {
            Thread.sleep(SHORT_DELAY_MS);
            t.interrupt();
            t.join();
        } catch(InterruptedException e){
            unexpectedException();
        }
    }