Cloneable

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// Interface Cloneable defined in package java.lang

/** Marker interface */
/** 实现Cloneable 接口的类标记为可克隆的，而且它的对象可以使用在
* Object 类中定义的clone() 方法克隆
* protected native Object clone() throws CloneNotSupportedException
*/

import java.util.Date;

interface Ediable {

}

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 Date();
   }

   public int getId() {
       return id;
   }

   public double getArea() {
       return area;
   }

   public Date getWhenBuilt() {
       return whenBuilt;
   }

   public Object clone() throws CloneNotSupportedException {
       Object o = super.clone(); // Shallow copy
       // Deep copy
       ((House) o).whenBuilt = (Date) whenBuilt.clone();
       return o;
   }

   public int compareTo(Object o) {
       if(area > ((House) o).area)
           return 1;
       else if(area > ((House) o).area)
           return -1;
       else
           return 0;
   }
}

public class Test {
   public static void main(String[] args) throws CloneNotSupportedException {
       House house1 = new House(1, 140);
       System.out.println(house1.getWhenBuilt());

       House house2 = (House) house1.clone();
       System.out.println(house2.getWhenBuilt());

       System.out.println(house1.getWhenBuilt() == house2.getWhenBuilt());
   }
}

Sat May 10 02:33:57 CST 2014
Sat May 10 02:33:57 CST 2014
false

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