threadwaitsleeper.java

来自「反向的AJAX。最大的特性是我们成为反向的Ajax。DWR1.x允许你用java」· Java 代码 · 共 87 行

/*
 * Copyright 2005 Joe Walker
 *
 * 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.directwebremoting.dwrp;

/**
 * The simplest type of Sleeper that just uses {@link #wait()} and
 * {@link #notify()} to halt a Thread and restart it.
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class ThreadWaitSleeper implements Sleeper
{
    /* (non-Javadoc)
     * @see org.directwebremoting.dwrp.PollHandler.Sleeper#goToSleep()
     */
    public void goToSleep(Runnable onAwakening)
    {
        synchronized (sleepLock)
        {
            try
            {
                while (!wakeUpCalled)
                {
                    sleepLock.wait();
                }
            }
            catch (InterruptedException ex)
            {
                Thread.interrupted();
            }
            finally
            {
                onAwakening.run();
            }
        }
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.dwrp.PollHandler.Sleeper#wakeUp()
     */
    public void wakeUp()
    {
        synchronized (wakeUpCalledLock)
        {
            if (wakeUpCalled)
            {
                return;
            }

            wakeUpCalled = true;
        }

        synchronized (sleepLock)
        {
            sleepLock.notifyAll();
        }
    }

    /**
     * All operations that involve going to sleep of waking up must hold this
     * lock before they take action.
     */
    private final Object wakeUpCalledLock = new Object();

    /**
     * Has wakeUp been called?
     */
    private transient boolean wakeUpCalled = false;

    /**
     * The object to lock on
     */
    private final Object sleepLock = new Object();
}