// From text by Cay Horstmann: Java Concepts, 2005.
//cmc: modified in lecture (except cmc comments), 2/27/09

import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JComponent;

import java.awt.Color; //cmc: to color cars

/**
   This component draws two car shapes.
*/
public class CarComponent extends JComponent
{ 

   //cmc: cars changed to instance variables
   private Car car1, car2;
 
   public void paintComponent(Graphics g)
   {  
      Graphics2D g2 = (Graphics2D) g;

      if (car1 == null) { //cmc: create cars first call only
          car1 = new Car(0, 0, Color.RED); //cmc: in color
      
          int x = getWidth() - Car.WIDTH;
          int y = getHeight() - Car.HEIGHT;

          car2 = new Car(x, y, Color.BLUE);
      }
      car1.draw(g2);
      car2.draw(g2);      
   }

   //cmc: sets the cars in motion
   public void animate() {

       for (int i=0; i<20; i++) {

           // waste one-half second (500 milliseconds)
           try{ Thread.sleep(500); }
           catch (InterruptedException e) {}

           // move the cars
           car1.forward(5);
           car2.backward(10);

           // special method eventually calls paintComponent again
           repaint();
        }

    }
}