/* Applet to display a countdown to an event in the future
 *  (This is java 1.02 compatible code.)
 *
 *  By Terry R. McConnell
 *
 * Call from HTML as follows:

<APPLET CODE="CountDownApplet.class" WIDTH=150 HEIGHT=40>
<PARAM NAME=targetDate VALUE="Fri 1 Jan 1999 00:00:00 EST">

Things you might want to change in the code:
	- The font
	- The background color
	- The time between updates
	- The string to be printed when the date cannot be parsed
	- The string to be printed when time expires

*/

import java.awt.Graphics;
import java.awt.Color;
import java.awt.Font;
import java.util.Date;
import java.util.Date.*;


public class CountDownApplet extends java.applet.Applet
        implements Runnable {

        private Font myFont = new Font("TimesRoman",Font.BOLD,12);
	private long targetTime; // Time we are counting down to. Times
                                 // are in milliseconds since 1970
	private Date DateNow;
        private Thread myThread;
        private static final int pause = 1000; // time between steps
                                               // in milliseconds

	private static final String expiredString = "Expired";
	private static final String invalidString = "Invalid Date";
	private boolean initOk = true;

        // The init method is called when the applet starts

        public void init(){

		setBackground(Color.red);
	 	String td = getParameter("targetDate");
		if(td == null){
			System.out.println("Unable to parse target date");
			initOk = false;
		}
		else {
			targetTime = Date.parse(td);
		}
        }

        // The start method is called everytime the applet is (re)started
        // All this one does is begin a thread of execution. 

        public void start(){
                if(myThread == null){
                myThread = new Thread(this);
                myThread.start();
                }
        }

        public void stop(){
                if(myThread != null){
                        myThread.stop();
                        myThread = null;  // allow garbage collection
                }
        }

	// Called when a new thread is started 

        public void run(){

                 while(true){
                        repaint();
                        try { Thread.sleep(pause);}
                        catch (InterruptedException e) {}
                }
        }



/* Update the countdown field. Since we create a new Date object
   every time this is called, the countdown is updated. Old date
   objects can be garbage collected. 
*/

	public void paint(Graphics g) {

		long secsOffset = 0L;

		if(initOk){
			g.setFont(myFont);
			DateNow = new Date();
			secsOffset =  (targetTime - DateNow.getTime())/1000L;
			if(secsOffset >= 0L){
				g.drawString("" + Long.toString(secsOffset),10,15);
			}
			else {
				g.drawString(expiredString,10,15);
			}
		}
		else { 
			g.drawString(invalidString,10,15);
		}
        }               
}