/*
 * Copyright 2005 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.wamblee.concurrency;

import org.wamblee.test.EventTracker;
import org.wamblee.test.TimingUtils;

import junit.framework.TestCase;

/**
 * Tests for the JVMLock.
 */
public class JvmLockTest extends TestCase {

    private static final int SLEEP_TIME = 1000;

    private static final String STARTED = "started";

    private static final String ACQUIRED = "acquired";

    private static final String RELEASED = "released";

    private JvmLock _lock;

    private EventTracker<String> _tracker;

    /*
     * (non-Javadoc)
     * 
     * @see junit.framework.TestCase#setUp()
     */
    @Override
    protected void setUp() throws Exception {
        _lock = new JvmLock();
        _tracker = new EventTracker<String>();
    }

    private Thread runThread() {
        Thread t = new Thread(new Runnable() {
            public void run() {
                _tracker.eventOccurred(STARTED);
                _lock.acquire();
                _tracker.eventOccurred(ACQUIRED);
                TimingUtils.sleep(SLEEP_TIME);
                _lock.release();
                _tracker.eventOccurred(RELEASED);
            };
        });
        t.start();
        return t;
    }

    /**
     * Tests the operation of the lock.
     */
    public void testLock() throws InterruptedException {
        Thread t1 = runThread();
        Thread t2 = runThread();
        TimingUtils.sleep(SLEEP_TIME / 10); // give threads a chance to start
        // up.
        assertEquals(2, _tracker.getEventCount(STARTED)); // both threads
        // should have
        // started.
        assertEquals(1, _tracker.getEventCount(ACQUIRED)); // one thread has
                                                            // acquired the
                                                            // lock.
        TimingUtils.sleep(SLEEP_TIME);
        assertEquals(2, _tracker.getEventCount(ACQUIRED)); // now the other
                                                            // thread could also
                                                            // acquire the lock
        assertEquals(1, _tracker.getEventCount(RELEASED)); // and the first
                                                            // thread has
                                                            // released it.
        TimingUtils.sleep(SLEEP_TIME);
        assertEquals(2, _tracker.getEventCount(RELEASED)); // both threads
                                                            // should be
                                                            // finished.
        t1.join();
        t2.join();
    }
}