public interface Implementor {
 /**
  * 實現(xiàn)抽象部分的具體方法
  */
 public void operationImpl();
}

public class ConcreteImplementorA implements Implementor {
 @Override
 public void operationImpl() {
  System.out.println("ConcreteImplementorA");
 }
}

public class ConcreteImplementorB implements Implementor {
 @Override
 public void operationImpl() {
  System.out.println("ConcreteImplementorB");
 }
}

public abstract class Abstraction {
 private Implementor mImplementor;

 /**
  * 通過實現(xiàn)部分對象的引用構(gòu)造抽象部分的對象
  *
  * @param implementor 實現(xiàn)部分對象的引用
  */
 public Abstraction(Implementor implementor){
  mImplementor = implementor;
 }

 public void operation(){
  mImplementor.operationImpl();
 }
}

public class RefinedAbstraction extends Abstraction {

 /**
  * 通過實現(xiàn)部分對象的引用構(gòu)造抽象部分的對象
  *
  * @param implementor 實現(xiàn)部分對象的引用
  */
 public RefinedAbstraction(Implementor implementor) {
  super(implementor);
 }

 public void refinedOperation(){
  //對 Abstraction中的方法進行擴展。

  System.out.println("refinedOperation");
  operation();
 }
}

public class Client {

 public static void main(String[] args){
  Abstraction abstraction = new RefinedAbstraction(new ConcreteImplementorA());
  abstraction.operation();
 }
}