Traffic Light -- Very Simple

Hi, not to sure how I can get this code working. The teacher wants us to use the Circle class that was in the book even though we don't need all of it's functionality but I'm not sure how to get it to paint the circles from within the switch statment in the TrafficLightPanel class. Just need some guidance on this one. Thanks

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

import javax.swing.JFrame;

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?      
//********************************************************************

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

public class TrafficLightPanel extends JPanel
{
 
  private int state = 1;
  private JButton push;
  private Circle redLight, yellowLight, greenLight;
  //----------------------------------------------------------------------------------
  //  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
      //----------------------------------------------------------------------------------------------
      
      //----------------------------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 page)
            {
                  super.paintComponent (page);
                  
            
                  redLight.draw(page);      
            }

      //-------------------------------------------------------------------------------------------
      // 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;
                         //      break;
            //            case 2:
             //                  greenLight.draw(page);
             //                  state = state + 1;
             //                  break;
            //            case 3:
              //                  yellowLight.draw(page);
              //                  state = 1;                              
            //                  break;            
            //            }      
            //      
            //      repaint();
            }
      
      }
}








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

import java.awt.*;

public 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;
   }
}