import java.awt.Component;

/*****************************************
 * An class that handles the specifics
 * of animation.  This class can be used to
 * animate a component
*****************************************/ 

public class Animator implements Runnable{
        
    public Animator(Component comp){
        this.comp = comp;
    }
    
    public void start(){
        if (animationThread == null){
            animationThread = new Thread(this); 
            animationThread.start(); 
        }
    }
    
    public void stop(){ 
        animationThread = null; 
    } 
    
    public void run(){ 
        while (Thread.currentThread() == animationThread){ 
            comp.repaint(); 
            try{ 
                Thread.currentThread().sleep(delay); 
            } 
            catch(InterruptedException e){/* don't do anything*/} 
        } 
    }
    
    // Java bean pattern to enforce encapsulation
    public void setDelay(int delay){
        this.delay = delay;
    }
    // Java bean pattern to enforce encapsulation
    public int getDelay(){
        return delay;
    }
    
    // the thread that does the redrawing
    private Thread animationThread = null; 
    // how often the thread redraws itself
    private int delay = 100;
    // the component to be animated
    private Component comp; 
}