// TestCloneable.java: Cloning objects
public class TestCloneable {
  /** Main method */
  public static void main(String[] args) {
    // Declare and create an instance of CloneableCircle
    CloneableCircle c1 = new CloneableCircle(5);
    CloneableCircle c2 = (CloneableCircle)c1.clone();

    System.out.println("After cloning c1 to c2");

    // Check if two variables point to the same object
    System.out.println("Do c1 and c2 reference the same object? "
      + (c1 == c2));

    // Check if the date field of two objects are the same
    System.out.println("Do c1.date and c2.date reference " +
      "the same object? " + (c1.date == c2.date));

    System.out.println("Is a CloneableCircle object cloneable? "
      + (c1 instanceof Cloneable));

    // Check if a Circle object is cloneable
    Circle c = new Circle();
    System.out.println("Is a Circle object cloneable? "
      + (c instanceof Cloneable));
  }
}

// CloneableCircle is a subclass of Circle, which implements the
// Cloneable interface
class CloneableCircle extends Circle implements Cloneable {
  // Store the date when the object is created
  java.util.Date date = new java.util.Date();

  /** Construct a CloneableCircle with a specified radius */
  public CloneableCircle(double radius) {
    super(radius);
  }

  /** Override the protected clone method defined in the Object
     class, and strengthen its accessibility */
  public Object clone() {
    try {
      return super.clone();
    }
    catch (CloneNotSupportedException ex) {
      return null;
    }
  }
}

public class Circle extends GeometricObject {
  private double radius;

  public Circle() {
  }

  public Circle(double radius) {
    this.radius = radius;
  }

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

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

  /** Return area */
  public double getArea() {
    return radius * radius * Math.PI;
  }

  /** Return diameter */
  public double getDiameter() {
    return 2 * radius;
  }

  /** Return perimeter */
  public double getPerimeter() {
    return 2 * radius * Math.PI;
  }

  /* Print the circle info */
  public void printCircle() {
    System.out.println("The circle is created " + getDateCreated() +
      " and the radius is " + radius);
  }
}

public abstract class GeometricObject {
  private String color = "white";
  private boolean filled;
  private java.util.Date dateCreated;

  /** Construct a default geometric object */
  protected GeometricObject() {
    dateCreated = new java.util.Date();
  }

  /** Return color */
  public String getColor() {
    return color;
  }

  /** Set a new color */
  public void setColor(String color) {
    this.color = color;
  }

  /** Return filled. Since filled is boolean,
     so, the get method name is isFilled */
  public boolean isFilled() {
    return filled;
  }

  /** Set a new filled */
  public void setFilled(boolean filled) {
    this.filled = filled;
  }

  /** Get dateCreated */
  public java.util.Date getDateCreated() {
    return dateCreated;
  }

  /** Return a string representation of this object */
  public String toString() {
    return "created on " + dateCreated + "\ncolor: " + color +
      " and filled: " + filled;
  }

  /** Abstract method getArea */
  public abstract double getArea();

  /** Abstract method getPerimeter */
  public abstract double getPerimeter();
}