/* ParticleCanvas.java
 */ 

import java.awt.*;

class ParticleCanvas extends Canvas
{
   private Particle[] particles; // = new Particle[10];

   ParticleCanvas(int size) {
     setSize(new Dimension(size, size));
   }

   // Intended to be called by applet
   synchronized void setParticles(Particle[] ps) {
     if (ps == null)
       throw new IllegalArgumentException("Cannot set null");

     System.out.println( "setParticles::ps.length: " + ps.length );
     particles = new Particle[ps.length];
     particles = ps;
   }

   protected synchronized Particle[] getParticles() {
     return particles;
   }

   public void paint(Graphics g) { // override Canvas.paint
     Particle[] ps = getParticles();

     for (int i = 0; i < ps.length; ++i)
       ps[i].draw(g);
   }
}