public class House implements Cloneable, Comparable {
  private int id;
  private double area;
  private java.util.Date whenBuilt;
  
  public House(int id, double area) {
    this.id = id;
    this.area = area;
    whenBuilt = new java.util.Date();
  }
  
  public double getId() {
    return id;
  }
  
  public double getArea() {
    return area;
  }

  public java.util.Date getWhenBuilt() {
    return whenBuilt;
  }

  /** Override the protected clone method defined in the Object
    class, and strengthen its accessibility */
  public Object clone() throws CloneNotSupportedException {
    return super.clone();
  }
  
  /** Implement the compareTo method defined in Comparable */
  public int compareTo(Object o) {
    if (area > ((House)o).area)
      return 1;
    else if (area < ((House)o).area)
      return -1;
    else
      return 0;
  }  
}