14.2

import java.awt.*;
import java.util.Scanner;

import javax.swing.*;

public class Test extends JFrame {
  public static void main(String[] args){
      Comparable c1 = new ComparableCircle();
      System.out.println("c1 is "+new ComparableCircle());
      System.out.println(c1);
      Comparable c2 = new ComparableCircle(2.0);
      
      System.out.println("the c1's area is: "+((Circle)c1).getArea());
      System.out.println("the c2's area is: "+((Circle)c2).getArea());
      
      Comparable c3 = null ;
      System.out.println("compare's result is :"+c1.compareTo(c2));
      
      switch(c1.compareTo(c2))
      {
      case 1: { c3 = c1; break;}
      case -1: { c3 = c2; System.out.println("c3 = c2");break;}
      case 0: {c3= c1; break;}
      }
      System.out.println("c1 address is"+c1+"
"+"c2 address is"+c2+"
"+"c3 address is"+c3);
      if(c3 instanceof Circle)
      System.out.print("the bigger area is : "+((Circle)c3).getArea()+"
");
      else
          System.out.println("c1 is not ComparableCircle type");
  }  
}

public class ComparableCircle extends Circle implements Comparable{

    public ComparableCircle()
    {
        
    }
    public ComparableCircle(double radius) {
        // TODO Auto-generated constructor stub
        super(radius);
    }

    @Override
    public int compareTo(Object o) throws ClassCastException{
        // TODO Auto-generated method stub
        try{
            if(this.getArea() > ((ComparableCircle)o).getArea())
            return 1;
        else if(this.getArea() < ((ComparableCircle)o).getArea())
            return -1;
        else
        return 0;
    }
    catch(ClassCastException  ex)
    {
        System.out.println("the class type cannot be transfered!");
        return 0;
    }
    }
}

// Circle.java: The circle class that extends GeometricObject
public class Circle  {
  private double radius;

  /**Default constructor*/
  public Circle() {
    this(1.0);
  }

  /**Construct circle with a specified radius*/
  public Circle(double radius) {
    this(radius, "white", false);
  }

  /**Construct a circle with specified radius, filled, and color*/
  public Circle(double radius, String color, boolean filled) {
   
    this.radius = radius;
  }

  /**Return radius*/
  public double getRadius() {
    return radius;
  }

  /**Set a new radius*/
  public void setRadius(double radius) {
    this.radius = radius;
  }

  /**Implement the getArea method defined in GeometricObject*/
  public double getArea() {
    return radius*radius*Math.PI;
  }

  /**Implement the getPerimeter method defined in GeometricObject*/
  public double getPerimeter() {
    return 2*radius*Math.PI;
  }

  /**Override the equals() method defined in the Object class*/
  public boolean equals(Circle circle) {
    return this.radius == circle.getRadius();
  }

  /**Override the toString() method defined in the Object class*/
  public String toString() {
    return "[Circle] radius = " + radius;
  }
}