代理

//: reusing/SpaceShip.java

public class SpaceShip extends SpaceShipControls {
  private String name;
  public SpaceShip(String name) { this.name = name; }
  public String toString() { return name; }
  public static void main(String[] args) {
    SpaceShip protector = new SpaceShip("NSEA Protector");
    protector.forward(100);
  }
} ///:~
//: reusing/SpaceShipDelegation.java

public class SpaceShipDelegation {
  private String name;
  private SpaceShipControls controls =
    new SpaceShipControls();
  public SpaceShipDelegation(String name) {
    this.name = name;
  }
  // Delegated methods:
  public void back(int velocity) {
    controls.back(velocity);
  }
  public void down(int velocity) {
    controls.down(velocity);
  }
  public void forward(int velocity) {
    controls.forward(velocity);
  }
  public void left(int velocity) {
    controls.left(velocity);
  }
  public void right(int velocity) {
    controls.right(velocity);
  }
  public void turboBoost() {
    controls.turboBoost();
  }
  public void up(int velocity) {
    controls.up(velocity);
  }
  public static void main(String[] args) {
    SpaceShipDelegation protector =
      new SpaceShipDelegation("NSEA Protector");
    protector.forward(100);
  }
} ///:~

 通过生成一个私有的对象  在内部使用 可以做更多的事情  这个叫代理