Traffic Light -- Very Simple

//****************************************************************************************
// TrafficLight.java                   Author: Romeo Theriault
//
// Not sure just yet.
//****************************************************************************************

import javax.swing.JFrame;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class TrafficLight
{
     //-----------------------------------------------------------------------------
     // Creates the main program frame.
     //-----------------------------------------------------------------------------
     public static void main (String[] args)
     {
          JFrame frame = new JFrame ("Traffic Light");
          frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);

          frame.getContentPane().add(new TrafficLightPanel());

          frame.pack();
          frame.setVisible(true);
     }
}






//********************************************************************
//  TrafficLightPanel.java       Authors: Romeo Theriault
//
//  Demonstrates a graphical user interface and an event listener.
//
//  Do i need to make the Random generator private or public?
//********************************************************************


class TrafficLightPanel extends JPanel
{

  private int state = 1;
  private JButton push;
  private Circle redLight, yellowLight, greenLight, light;

  Graphics page = null;
  //----------------------------------------------------------------------------------
  //  Constructor: Sets up the main characteristics of the traffic light.
  //----------------------------------------------------------------------------------
  public TrafficLightPanel ()
  {


     //----------------------------Image stuff---------------------------------------------------

          redLight = new Circle (50, Color.red, 35, 50);
          greenLight = new Circle (50, Color.green, 35, 125);
          yellowLight = new Circle (50, Color.yellow, 35, 200);
          setBackground (Color.black);                   // set background color
          setPreferredSize (new Dimension(120, 250));   // set the size of the whole window
          light = new Circle (50, Color.red, 35, 50);



     //----------------------------------------------------------------------------------------------

     //----------------------------Button stuff----------------------------------------------------


          push = new JButton ("Change!");  // Makes a new button called "push"
          push.addActionListener (new ButtonListener());   // Makes a new button listener attached to button "push"

          add (push);     // adds the button to the panel
     //----------------------------------------------------------------------------------------------

  }

     //---------------------------------------------------------------------------------
     //  Draw a traffic light
     //---------------------------------------------------------------------------------
          public void paintComponent (Graphics g)
          {
               super.paintComponent (g);

                        page = g;
               light.draw(g);
          }

     //-------------------------------------------------------------------------------------------
     // Represents a listener for button "push" events.
     //---------------------------------------------------------------------------------------------
     private class ButtonListener implements ActionListener
     {
        public void actionPerformed (ActionEvent event)
          {


               switch (state)
                {
                    default:
                        redLight.draw(page);
                          state = state + 1;
                          light = new Circle (50, Color.red, 35, 50);
                          break;
                    case 2:
                          greenLight.draw(page);
                          state = state + 1;
                          light = greenLight;
                          break;
                    case 3:
                           yellowLight.draw(page);
                           state = 1;
                           light = yellowLight;
                         break;
                    }

               repaint();
          }

     }
}








//********************************************************************
//  Circle.java       Author: Lewis/Loftus
//
//  Represents a circle with a particular position, size, and color.
//********************************************************************


class Circle
{
   private int diameter, x, y;
   private Color color;

   //-----------------------------------------------------------------
   //  Constructor: Sets up this circle with the specified values.
   //-----------------------------------------------------------------
   public Circle (int size, Color shade, int upperX, int upperY)
   {
      diameter = size;
      color = shade;
      x = upperX;
      y = upperY;
   }

   //-----------------------------------------------------------------
   //  Draws this circle in the specified graphics context.
   //-----------------------------------------------------------------
   public void draw (Graphics page)
   {
      page.setColor (color);
      page.fillOval (x, y, diameter, diameter);
   }

   //-----------------------------------------------------------------
   //  Diameter mutator.
   //-----------------------------------------------------------------
   public void setDiameter (int size)
   {
      diameter = size;
   }

   //-----------------------------------------------------------------
   //  Color mutator.
   //-----------------------------------------------------------------
   public void setColor (Color shade)
   {
      color = shade;
   }

   //-----------------------------------------------------------------
   //  X mutator.
   //-----------------------------------------------------------------
   public void setX (int upperX)
   {
      x = upperX;
   }


   //-----------------------------------------------------------------
   //  Y mutator.
   //-----------------------------------------------------------------
   public void setY (int upperY)
   {
      y = upperY;
   }

   //-----------------------------------------------------------------
   //  Diameter accessor.
   //-----------------------------------------------------------------
   public int getDiameter ()
   {
      return diameter;
   }

   //-----------------------------------------------------------------
   //  Color accessor.
   //-----------------------------------------------------------------
   public Color getColor ()
   {
      return color;
   }

   //-----------------------------------------------------------------
   //  X accessor.
   //-----------------------------------------------------------------
   public int getX ()
   {
      return x;
   }

   //-----------------------------------------------------------------
   //  Y accessor.
   //-----------------------------------------------------------------
   public int getY ()
   {
      return y;
   }
}