org.rifidi.utilities.Timer.java Source code

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Here is the source code for org.rifidi.utilities.Timer.java

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/*
 *  TimeController.java
 *
 *  Created:   Jun 20, 2006
 *  Project:   RiFidi Emulator - A Software Simulation Tool for RFID Devices
 *              http://www.rifidi.org
 *              http://rifidi.sourceforge.net
 *  Copyright:   Pramari LLC and the Rifidi Project
 *  License:   Lesser GNU Public License (LGPL)
 *              http://www.opensource.org/licenses/lgpl-license.html
 */
package org.rifidi.utilities;

import java.util.Observable;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * This class waits for x amout of time, then notifies observes. It has a
 * suspend() and a resume() methods for pausing and un-pausing the timer.
 * 
 * @author Matthew Dean - matt@pramari.com
 * @author Kyle Neumeier - kyle@pramari.com
 */
public class Timer extends Observable implements Runnable {

    /**
     * The logger for this class.
     */
    private static Log logger = LogFactory.getLog(Timer.class);

    /**
     * Amount of time left to wait. For example, if this timer is supposed to
     * wait 10 seconds, and after it waits 10, it realizes that the timer was
     * paused for 3 seconds, this variable will be set to 3 seconds
     */
    private long timeLeftToWait;

    /**
     * Weather or not this timer is suspended or not
     */
    private boolean suspended = false;

    /**
     * The amount of time that the timer was paused
     */
    private long pausedTime = 0;

    /**
     * If the timer wakes up and realizes it is in a suspend state, this is the
     * amount of time between when it wakes up and when the timer is resumed
     */
    private long extraPauseTime = 0;

    /**
     * This is the time that the timer was suspended last. It is used to figure
     * out how long the timer was suspended
     */
    private long lastSuspendTime = 0;

    /**
     * An optional name for the timer.
     */
    private String name;

    private boolean stopped;

    /**
     * Constructs a timeController, which will fire the given trigger
     * 
     * @param timeToWait
     *            The time, in milliseconds.
     */
    public Timer(long timeToWait) {
        this.timeLeftToWait = timeToWait;
    }

    /**
     * Constructs a timeController, which will fire the given trigger
     * 
     * @param timeToWait
     *            The time, in milliseconds.
     */
    public Timer(long timeToWait, String name) {
        this.timeLeftToWait = timeToWait;
        this.name = name;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Runnable#run()
     */
    public void run() {
        boolean done = false;
        stopped = false;
        while (!done) {
            sleepSome(timeLeftToWait);
            extraPauseTime = 0;
            while (this.suspended) {
                sleepSome(500);
                extraPauseTime += 500;
            }
            timeLeftToWait = timeLeftToWait - (timeLeftToWait - (pausedTime - extraPauseTime));
            if (timeLeftToWait <= 0) {
                done = true;
            } else {
                synchronized (this) {
                    pausedTime = 0;
                }
            }
        }

        if (!stopped) {
            this.setChanged();
            if (this.name != null) {
                this.notifyObservers(name);
            } else {
                this.notifyObservers();
            }
        }
    }

    private void sleepSome(long millis) {
        try {
            Thread.sleep(millis);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void suspend() {
        logger.debug("Timer suspended");
        suspended = true;
        lastSuspendTime = System.currentTimeMillis();
    }

    public void resume() {
        logger.debug("Timer resumed");
        suspended = false;
        synchronized (this) {
            pausedTime += System.currentTimeMillis() - lastSuspendTime;
        }
    }

    public void stop() {
        this.stopped = true;
    }
}