/* An application that reads data from a file, Figures.txt, that contains coordinates for circles and squares.  It stores these in an array of Figures.  Then it displays the figures on the window frame.  It uses  inheritance and polymorphism. */

import java.awt.*;
import java.awt.event.*;
import java.io.*;

public class Figures
{
     public static void main (String [] args)
     {
          FigureFrame frame = new FigureFrame ();
          frame.addWindowListener (new WindowCloser ());
          frame.show ();
     }
} // class Figures

class WindowCloser extends WindowAdapter
{
     public void windowClosing (WindowEvent e) {System.exit (0);}
} // class WindowCloser
 
// Class that creates a frame and adds buttons and a canvas to it.
class FigureFrame extends Frame
{
     private FigureList figureList;
     private Graphics g;
     private Button start, next;
     private Canvas canvas;
     private Panel panel;
 
     FigureFrame ()
     {
          super ("Figures");
          setSize (300, 300);
          setBackground (Color.cyan);
          panel = new Panel ();
          start = new Button ("Start");
          start.addActionListener (new StartListener ());
          panel.add (start);
          next = new Button ("Next");
          next.addActionListener (new NextListener ());
          panel.add (next);
          canvas = new Canvas ();
          canvas.setSize (200, 200);
          canvas.setBackground (Color.white);
          panel.add (canvas);
          add (panel);
          figureList = new FigureList ();
     } // constructor
 
     /* Inner class that listens for the start button.  It gets the graphics for the canvas, reads in the list of coordinates and then displays the first figure. */
     class StartListener implements ActionListener
     {
          public void actionPerformed (ActionEvent e)
          {
               g = canvas.getGraphics ();
               figureList.readList ();
               figureList.displayNextFigure (g);
          } // method actionPerformed
     } // class StartListener
 
     // Inner class that displays the next figure.
     class NextListener implements ActionListener
     {
          public void actionPerformed (ActionEvent e)
          {
               figureList.displayNextFigure (g);
          } // method actionPerformed
     } // class NextListener
} // class Figures

// FigureList handles the array of Figures.  It reads them in and then displays the next one.
class FigureList
{
     private Figure [] list;
     private int listSize;
     final int maxSize = 10;
     private int nextLocation;
 
     FigureList ()
     {
          list = new Figure [maxSize];
          listSize = 0;
          nextLocation = 0;
     } // constructor
 
     // Method that reads the data in from the file and stores it in the array, list.
     public void readList ()
     {
          Figure figure;
          try
          {
               BufferedReader figureFile = new BufferedReader ( new InputStreamReader (new FileInputStream ("Figures.txt")));
               String type = figureFile.readLine ();
               while ((type != null) && (listSize < maxSize))
               {
                    if (type.equals ("Circle")) figure = new Circle (type);
                    else figure = new Square (type);
                    figure.readFigure (figureFile);
                    list [listSize] =  figure;
                    listSize ++;
                    type = figureFile.readLine ();
               }
               figureFile.close ();
          } catch (IOException e) {System.out.println ("IO Error");}
          catch (NumberFormatException e) {System.out.println ("Number Error.");}
     } // method readList
 
     // Method that displays the next figure and then updates the nextLocation variable.
     public void displayNextFigure (Graphics g)
     {
          if (nextLocation < listSize) list [nextLocation].displayFigure (g);
          else System.out.println ("All figures displayed");
          nextLocation ++;
     } // method displayNextFigure
} // class FigureList

// Figure is the super class that reads in the coordinates.
class Figure
{
     protected String type;
     protected int x, y;
     protected Color color;
 
     Figure (String t) { type = t;} // constructor
 
     public void readFigure (BufferedReader infile) throws IOException
     {
          x = Integer.parseInt (infile.readLine ());
          y = Integer.parseInt (infile.readLine ());
     } // method readFigure
 
     public void displayFigure (Graphics g)
     {
          g.setColor (color);
     } // method displayFigure
}// class Figure

/* The Circle class inherits the x and y coordinates from the Figure class.  It then reads in the diameter of the circle. */
class Circle extends Figure
{
     private int diameter;
 
     Circle (String t) {super (t);} // constructor
 
     public void readFigure (BufferedReader infile) throws IOException
     {
          super.readFigure (infile);
          diameter = Integer.parseInt (infile.readLine ());
          color = Color.red;
     } // method readFigure
 
     public void displayFigure (Graphics g)
     {
          super.displayFigure (g);
          g.fillOval (x, y, diameter, diameter);
     } // method displayFigure
} // class Circle

/* The Square class inherits the x and y coordinates from the Figure class and the reads in the length of the side. */
class Square extends Figure
{
     private int side;
 
     Square (String t) { super (t); } // constructor
 
     public void readFigure (BufferedReader infile) throws IOException
    {
         super.readFigure (infile);
          color = Color.green;
          side = Integer.parseInt (infile.readLine ());
     } // method readFigure
 
     public void displayFigure (Graphics g)
     {
          super.displayFigure (g);
          g.fillRect (x, y, side, side);
     } // method displayFigure
} // class Square