horrorflick.java

来自「Java编程思想这本书很好」· Java 代码 · 共 34 行

//: appendixa:HorrorFlick.java
// You can insert Cloneability at any level of inheritance.
// From 'Thinking in Java, 3rd ed.' (c) Bruce Eckel 2002
// www.BruceEckel.com. See copyright notice in CopyRight.txt.
package appendixa;
import java.util.*;

class Person {}
class Hero extends Person {}
class Scientist extends Person implements Cloneable {
  public Object clone() {
    try {
      return super.clone();
    } catch(CloneNotSupportedException e) {
      // This should never happen: It's Cloneable already!
      throw new RuntimeException(e);
    }
  }
}
class MadScientist extends Scientist {}

public class HorrorFlick {
  public static void main(String[] args) {
    Person p = new Person();
    Hero h = new Hero();
    Scientist s = new Scientist();
    MadScientist m = new MadScientist();
    //! p = (Person)p.clone(); // Compile error
    //! h = (Hero)h.clone(); // Compile error
    s = (Scientist)s.clone();
    m = (MadScientist)m.clone();
  }
} ///:~