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

class Position extends Observable {

	private int x;
	private int y;
	private int ancx;
	private int ancy;
	private int mv;
	private int[][] mouvements = new int[1001][2];

	public void incx() { inc("x"); }
	public void incy() { inc("y"); }
	public int ancx() { return ancx; }
	public int ancy() { return ancy; }
	public int x() { return x ; }
	public int y() { return y ; }
	public int[][] mouvements() { return (this.mouvements); }
	public int nbMouvements() { return (mv); }

	Position () { x=0; y=0; ancx=x; ancy=y; mv=0; mouvements[0][0]=x; mouvements[0][1]=y; }

	synchronized private void inc(String lettre) {
		ancx=x ; ancy=y ;
		if (lettre=="x") x++; else y++;
		maj(lettre) ; 
	}
	
	private void maj(String lettre) {
//		System.out.println (mv+ " ("+ancx+","+ancy+")-->("+x+","+y+") par "+lettre) ;
		mv++; mouvements[mv][0]=x; mouvements[mv][1]=y;
		setChanged();
		notifyObservers();
	}
}

class testThread extends Thread {

	private String nom ;
	private Position pos ;

	public testThread (String nom, Position pos) { this.nom=nom ; this.pos=pos ; }

	public void run() {
		if (nom=="x") {
			for (int i=0;i<500;) {
				if ( (long)(Math.random() * 10) <1 )
					try { sleep((long)(Math.random() * 100)); } catch (InterruptedException e) {}
				pos.incx(); i++;
			}
		} else { 
			for (int i=0;i<500;) {
				try { sleep((long)(Math.random() * 10)); } catch (InterruptedException e) {}
				pos.incy(); i++;
			}
		}
	}		
}

public class TestLine extends Applet implements Observer {

	private Position position;
	private Thread un;
	private Thread deux;
	private int[][] mouvements;

	int x ;
	int y ;
	int xx ;
	int yy ;

	public void init() {
		x=0 ;
		position = new Position() ;
		mouvements = position.mouvements() ;
		position.addObserver(this) ;
		un = new testThread("x", position) ;
		deux = new testThread("y", position) ;
		un.start() ;
		deux.start() ;		
	}

	public void update(Observable o, Object arg) {
		Position pos = (Position)o ;
		x=pos.ancx() ; y=pos.ancy() ; xx=pos.x() ; yy=pos.y() ;
		repaint() ;
	}

	public void paint (Graphics G) {
		for (int i=1;i<position.nbMouvements();i++) {
			int [][] zog ;
			zog = position.mouvements() ;
			G.drawLine (zog[i][0], zog[i][1],
						zog[i+1][0], zog[i+1][1]);
		}					
	}

}