import java.util.*;
import java.rmi.*;
import java.rmi.server.*;
import java.rmi.registry.*;

public class Server extends UnicastRemoteObject implements RemoteServer {
  private int xLim = 500, yLim = 500;
  private Vector balls = new Vector();

  public static void main(String[] args) {
    try {
      Server server = new Server();
      LocateRegistry.createRegistry(1099);
      Naming.rebind("server", server);
      System.out.println("server bound");
    } catch(Exception e) {
      System.out.println("Exception generated: " + e.getMessage());
    }
  }

  public Server() throws RemoteException {}

  public synchronized void addBall() throws RemoteException {
    balls.add(new Ball());
  }

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

  public synchronized void pauseBalls() {
    for(int i = 0; i < balls.size(); i++) {
      if(((Ball)balls.elementAt(i)).active) {
        ((Ball)balls.elementAt(i)).active = false;
      } else {
        ((Ball)balls.elementAt(i)).active = true;
      }
    }
  }

  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 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 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) {}
      }
    }
  }
}