装饰器模式

public class DecoratorExer {
   public static void main(String[] args) throws Exception {
      House apartment = new Apartment();
      Decorator europeStyle = new EuropeStyle(apartment);

      apartment.show();
      europeStyle.show();
   }
}

abstract class House {
   abstract String getFacade();
   abstract String getBase();
   void show() {
      System.out.println(getFacade() + getBase());
   }
}

class Apartment extends House {
   @Override
   String getFacade() {
      return "外立面";
   }

   @Override
   String getBase() {
      return "楼房";
   }
}

abstract class Decorator extends House {
   House house;

   public Decorator(House house) {
      this.house = house;
   }
}

class EuropeStyle extends Decorator {
   public EuropeStyle(House house) {
      super(house);
   }

   @Override
   String getFacade() {
      return "淡黄色的" + house.getFacade();
   }

   @Override
   String getBase() {
      return "10层的" + house.getBase();
   }
}