程式碼

1. Duck

   package com.desmond.codebase.designpattern.overview.v4;
   
   /**
    * @author presleyli
    * @date 2018/10/17 上午8:11
    */
   public abstract class Duck {
       private Flyable flyable;
       private Quackable quackable;
   
       public Flyable getFlyable() {
           return flyable;
       }
   
       public void setFlyable
    
   (Flyable flyable) {
           this.flyable = flyable;
       }
   
       public Quackable getQuackable() {
           return quackable;
       }
   
       public void setQuackable(Quackable quackable) {
           this.quackable = quackable;
       }
   
       public void swim() {
           System.out.println("swimming.");
       }
   
       public
    
    abstract void display();
   
       public void quack() {
           System.out.println("original quack.");
       }
   
       public void fly() {
           System.out.println("original fly.");
       }
   }
   
   

2. MallrdDuck

   package com.desmond.codebase.designpattern.overview.v4;
   
   /**
    * @author presleyli
    * @date 2018/10/17 上午8:12
    */
    
   
   public class MallrdDuck extends Duck {
       @Override
       public void display() {
           System.out.println("green");
       }
   
       @Override
       public void quack() {
           this.getQuackable().quack();
       }
   
       @Override
       public void fly() {
           this.getFlyable().fly();
       }
   }
   
   

3. RubberDuck

   package com.desmond.codebase.designpattern.overview.v4;
   
   /**
    * @author presleyli
    * @date 2018/10/17 上午8:17
    */
   public class RubberDuck extends Duck {
       @Override
       public void display() {
           System.out.println("yellow");
       }
   
       @Override
       public void quack() {
           this.getQuackable().quack();
       }
   
       @Override
       public void swim() {
           super.swim();
       }
   
       @Override
       public void fly() {
           this.getFlyable().fly();
       }
   }
   
   

4. Flyable

   package com.desmond.codebase.designpattern.overview.v4;
   
   /**
    * Created by presleyli on 2018/10/17.
    */
   public interface Flyable {
       void fly();
   }
   
   

5. CanFly

   package com.desmond.codebase.designpattern.overview.v4;
   
   /**
    * @author presleyli
    * @date 2018/10/19 上午7:32
    */
   public class CanFly implements Flyable {
       @Override
       public void fly() {
           System.out.println("I can fly...");
       }
   }
   
   

6. CannotFly

   package com.desmond.codebase.designpattern.overview.v4;
   
   /**
    * @author presleyli
    * @date 2018/10/19 上午7:32
    */
   public class CannotFly implements Flyable {
       @Override
       public void fly() {
           // do nothing.
       }
   }
   
   

7. Quackable

   package com.desmond.codebase.designpattern.overview.v4;
   
   /**
    * Created by presleyli on 2018/10/17.
    */
   public interface Quackable {
       void quack();
   }
   
   

8. CanQuack

   package com.desmond.codebase.designpattern.overview.v4;
   
   /**
    * @author presleyli
    * @date 2018/10/19 上午7:33
    */
   public class CanQuack implements Quackable{
       @Override
       public void quack() {
           System.out.println("I can quack...");
       }
   }
   
   

9. CannotQuack

   package com.desmond.codebase.designpattern.overview.v4;
   
   /**
    * @author presleyli
    * @date 2018/10/19 上午7:33
    */
   public class CannotQuack implements Quackable{
       @Override
       public void quack() {
           // do nothing.
       }
   }
   
   

10. Main

    package com.desmond.codebase.designpattern.overview.v4;
    
    /**
     * @author presleyli
     * @date 2018/10/17 上午8:14
     */
    public class Main {
        public static void main(String[] args) {
            MallrdDuck mallrdDuck = new MallrdDuck();
            mallrdDuck.setFlyable(new CanFly());
            mallrdDuck.setQuackable(new CannotQuack());
            mallrdDuck.fly();
            mallrdDuck.quack();
    
            RubberDuck rubberDuck = new RubberDuck();
            rubberDuck.setFlyable(new CanFly());
            rubberDuck.setQuackable(new CanQuack());
            rubberDuck.fly();
            rubberDuck.quack();
    
        }
    }
    
    

11. Output:

    I can fly...
    I can fly...
    I can quack...