import java.awt.*;
public class Ball extends Thread {

    int w = 15;
    int h = 15;
    int x = 0;
    int y = 0;
    int dx = 2;
    int dy = 2;
    boolean cont = true;

    public Ball(int dx, int dy, int w, int h) {
        this.w = w;
        this.h = h;
        this.dx = dx;
        this.dy = dy;
    }

    public void run() {
        while (cont) {
            move();
            try {
                sleep(30);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    void draw(Graphics g) {
        //System.out.println("draw ball");
        g.fillOval(x, y, 5, 5);
    }

    public void move() {
        x += dx;
        y += dy;
        if (x <= 0) {
            x = 0;
            dx = -dx;
        }
        if (x >= w) {
            dx = -dx;
        }
        if (y <= 0) {
            y = 0;
            dy = -dy;
        }
        if (y >= h) {
            y = h;
            dy = -dy;
        }
    }

    public void tstop() {
        cont = false;
    }
}