import java.awt.*;
import java.util.*;
import java.applet.*;

abstract public class IcobjWorkspace extends Applet implements Runnable
{
  protected Image offscreenImage = null;
  protected Vector icobjsInTheWorkspace = new Vector();
  
  public IcobjWorkspace(){
    offscreenImage = createImage(size().width,size().height);
  }

  public void init(){ offscreenImage = createImage(size().width,size().height); }
  public void beginning(){}

  // painting
  public void update(Graphics g){ 
     synchronized(icobjsInTheWorkspace){ doubleBuffering(g); }
  }
  public void doubleBuffering(Graphics g){
     Graphics offscreenGraphics = offscreenImage.getGraphics();
     paint(offscreenGraphics);
     g.drawImage(offscreenImage,0,0,this);
  }
  public void paint(Graphics g){
     g.setColor(getBackground());
     g.fillRect(0,0,size().width,size().height);
     g.setColor(getForeground());
     for(int i=0;i<icobjsInTheWorkspace.size();i++) 
         ((Icobj)icobjsInTheWorkspace.elementAt(i)).paint(g);
  }

  // icobj management
  public void addIcobj(Icobj icobj){
    synchronized(icobjsInTheWorkspace){
	   icobjsInTheWorkspace.addElement(icobj);
	   icobj.setWorkspace(this);
    }
  }
  public void removeIcobj(Icobj icobj){
    synchronized(icobjsInTheWorkspace){ 
       icobjsInTheWorkspace.removeElement(icobj);
       icobj.stop();
    }
  }

  public void behaviors(){
    synchronized(icobjsInTheWorkspace){
       for(int i=0;i<icobjsInTheWorkspace.size();i++){
          Icobj icobj = (Icobj)icobjsInTheWorkspace.elementAt(i);
	      icobj.behavior();
       }
    }
  }

  public Vector icobjsInInfluence(Icobj icobj,int dim){
     Vector v = new Vector();
     synchronized(icobjsInTheWorkspace){
       for(int i=0;i<icobjsInTheWorkspace.size();i++){
	      Icobj tmp = (Icobj)icobjsInTheWorkspace.elementAt(i);
	      if(icobj.dist(tmp)<dim+tmp.radius+icobj.radius) v.addElement(tmp);
       }
     }
     return v;
  }
  
  public void stop(){
    synchronized(icobjsInTheWorkspace){
      for(int i=0; i<icobjsInTheWorkspace.size(); i++){
        removeIcobj((Icobj)icobjsInTheWorkspace.elementAt(i));
      }
    }
    System.out.println("applet stopped");
  }
}