Circle Panel GUI

// Arman Majumder
// Circle Panel GUI
// Requires Circle Class <Circle.java>  Included in bottom
   
   import java.awt.*;
   import java.awt.event.*;
   import java.util.*;
   import java.io.*;
   import javax.swing.*;
   import java.util.Random;
   
    public class CirclePanel extends JPanel
   {
      private Circle circle;
      private javax.swing.Timer timer;
   
       public CirclePanel(Color backColor, int width, int height)
      {
         setBackground(backColor);
         setPreferredSize(new Dimension(width, height));
         circle = new Circle(width / 2, height / 2, 50, Color.red);
         circle.setFilled(true);
         circle.setDirection(180);
         circle.setVelocity(5);
         timer = new javax.swing.Timer(5, new MoveListener());
         timer.start();
         
         addMouseListener(new PanelListener());
      }
   
       public void paintComponent(Graphics g)
      {
         super.paintComponent(g);
         circle.draw(g);
      }
      
       private class MoveListener implements ActionListener
      {
          public void actionPerformed(ActionEvent e)
         {
            int x = circle.getX();
            int radius = circle.getRadius();
            int width = getWidth();
            if (x - radius <= 0 || x + radius >= width)
               circle.turn(180);
            circle.move();
            repaint();
         }
      }
      
       private class PanelListener extends MouseAdapter
      {
          public void mousePressed(MouseEvent e)
         {
            int velocity = circle.getVelocity();
         
            if (velocity == 5)
            {
               circle.setVelocity(0);
               
               Random color = new Random();           
               int red = color.nextInt(256);
               int green = color.nextInt(256);
               int blue = color.nextInt(256); 
               Color backDrop = new Color(red, green, blue);
               setBackground(backDrop);
               repaint();
            }
            
            else
            {
               circle.setVelocity(5);
            
               Random color = new Random();           
               int red = color.nextInt(256);
               int green = color.nextInt(256);
               int blue = color.nextInt(256); 
               Color backDrop = new Color(red, green, blue);
               setBackground(backDrop);
               repaint();
            }
         }
      }

       public static void main(String [] args)
      {
         JFrame theGUI = new JFrame();
         theGUI.setTitle("Circle");
         theGUI.setSize(400, 400);
         theGUI.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         CirclePanel panel = new CirclePanel(Color.white, 400, 400);
         Container pane = theGUI.getContentPane();
         pane.add(panel);
         theGUI.setVisible(true);
      }
   }

//////////////////////////////////////////////////////////////////////////////////
//Circle Class 
// New Pogram
//////////////////////////////////////////////////////////////////////////////////

// Arman Majumder
// Corresponds with Circle Panel GUI <CirclePanel.java>
// Represents a circle

   import java.awt.*;
   import java.awt.event.*;
   import java.util.*;
   import java.io.*;
   import javax.swing.*;
   import java.util.Random;

    public class Circle
   {
      private int centerX, centerY, radius;
      private Color color;
      private int direction, velocity;
      private boolean filled;
   
       public Circle(int x, int y, int r, Color c)
      {
         centerX = x;
         centerY = y;
         radius = r;
         color = c;
         direction = 0;
         velocity = 0;
         filled = false;
      }
   
       public void draw(Graphics g)
      {
         Color oldColor = g.getColor();
         g.setColor(color);
      // Translates circle's center to rectangle's origin for drawing.
         if (filled)
            g.fillOval(centerX - radius, centerY - radius, radius * 2, radius * 2);
         else
            g.drawOval(centerX - radius, centerY - radius, radius * 2, radius * 2);
         g.setColor(oldColor);
      }
   
       public void fill(Graphics g)
      {
         Color oldColor = g.getColor();
         g.setColor(color);
      // Translates circle's center to rectangle's origin for drawing.
         g.fillOval(centerX - radius, centerY - radius, radius * 2, radius * 2);
         g.setColor(oldColor);
      }
   
       public boolean containsPoint(int x, int y)
      {
         int xSquared = (x - centerX) * (x - centerX);
         int ySquared = (y - centerY) * (y - centerY);
         int radiusSquared = radius * radius;
         return xSquared + ySquared - radiusSquared <= 0;
      }
   
       public void move(int xAmount, int yAmount)
      {
         centerX = centerX + xAmount;
         centerY = centerY + yAmount;
      }
   
       public int getRadius()
      {
         return radius;
      }
   
       public int getX()
      {
         return centerX;
      }
   
       public int getY()
      {
         return centerY;
      }
   
       public int getDirection()
      {
         return direction;
      }
   
       public void setVelocity(int v)
      {
         velocity = v;
      }  
   	 
       public int getVelocity()
      {
         return velocity;
      }
   
       public void setDirection(int d)
      {
         direction = d % 360;
      }
   
       public void turn(int degrees)
      {
         direction = (direction + degrees) % 360;
      }
   
   // Moves the circle in the current direction using its
   // current velocity
       public void move()
      {
         move((int)(velocity * Math.cos(Math.toRadians(direction))),
            (int)(velocity * Math.sin(Math.toRadians(direction))));
      }
   
       public void setFilled(boolean b)
      {
         filled = b;
      }
   }