import java.util.*;
import java.rmi.*;
import java.rmi.registry.*;
import java.rmi.server.*;
class Server implements RemoteServer{
	private Vector balls = null;
	
	public Server(){
		balls = new Vector();
	}
	
	public synchronized void addBall() throws RemoteException {
	  balls.add(new Ball());
	}

	private synchronized void removeBall(Ball ball) {
	  balls.remove(ball);
	}

	public synchronized void pauseBalls() throws RemoteException {
	  for(int i = 0; i < balls.size(); i++) {
	    Ball ball = (Ball)balls.elementAt(i);
	    ball.pause();
	  }
	}

	public synchronized Vector getBalls() throws RemoteException {
	  Vector ballsRaw = new Vector();
	  for(int i = 0; i < balls.size(); i++) {
	    Ball ball = (Ball)balls.elementAt(i);
	    ballsRaw.add(new Integer(ball.x));
	    ballsRaw.add(new Integer(ball.y));
	    ballsRaw.add(new Integer(ball.r));
	  }

	  return ballsRaw;
	}
	class Ball extends Thread {
		private int xLim = 500, yLim = 500;
		private boolean alive = true, active = true;
		private Random rnd = new Random();
		public int rMax = 70, r = rnd.nextInt(rMax), x = xLim / 2 - r / 2, y = yLim / 2 - r / 2, dx, dy, dMax = 5, ddx = 1, ddy = 1;
		Ball() {
			if(rnd.nextInt(2) == 1) ddx = -1;
			dx = (1 + rnd.nextInt(dMax)) * ddx;
			if(rnd.nextInt(2) == 1) ddy = -1;
			dy = (1 + rnd.nextInt(dMax)) * ddy;
			start();
		}
		public void pause(){
			if (active == true)
				active = false;
			else
				active = true;
		}
		public void run() {
			while(alive) {
				while(active) {
					if((x <= 0) || (x >= xLim - r)) { dx *= -1; r -= 2; }
					if((y <= 30) || (y >= yLim - r)) { dy *= -1; r -= 3; }

					if(r <= 0) {
						active = false;
						alive = false;
						removeBall(this);
					} else {
						x += dx;
						y += dy;
					}
					try { sleep(10 + r); } catch(Exception e) {}
				}
				try { sleep(50); } catch(Exception e) {}
			}
		}
	}
	public static void main(String[] args){
		/*if (System.getSecurityManager() == null) {
			System.setSecurityManager(new SecurityManager());
		}*/
		try {
			String name = "server";
			RemoteServer serv = new Server();
			RemoteServer stub =
				(RemoteServer) UnicastRemoteObject.exportObject(serv, 0);
			Registry registry = LocateRegistry.getRegistry();
			registry.rebind(name, stub);
			System.out.println("Server bound");
		} catch (Exception e) {
			System.err.println("Server exception:");
			e.printStackTrace();
		}

	}
}