设计模式-装饰模式

装饰模式:
把所需的功能按正确的顺序串联起来
动态的给一个对象添加一些职责

示例

class Person
{
    public Person() { }
    private string name;
    public Person(string name)
    {
        this.name = name;
    }
    public virtual void Show()
    {
        Console.Write("{0}穿着", name);
    }
}
class Finery : Person 
{
    protected Person component;

    public void Decorate(Person component)
    {
        this.component = component;
    }
    public override void Show()
    {
        component?.Show();
    }
}
class TShirts : Finery
{
    public override void Show()
    {
        base.Show();
        Console.Write("T恤 ");
    }
}
class BigTrouser : Finery
{
    public override void Show()
    {
        base.Show();
        Console.Write("垮裤 ");
    }
}
class Silpper : Finery
{
    public override void Show()
    {
        base.Show();
        Console.Write("拖鞋 ");
    }
}
//Client

Person ps = new Person("小明");
BigTrouser bt = new BigTrouser();
TShirts ts = new TShirts();
Silpper s = new Silpper();
bt.Decorate(ps);
ts.Decorate(bt);
s.Decorate(ts);
s.Show();
/*
小明穿着垮裤 T恤 拖鞋
*/

//java示例
//接口
public interface Shape {
   void draw();
}
//实现
public class Rectangle implements Shape {
 
   @Override
   public void draw() {
      System.out.println("Shape: Rectangle");
   }
}
public class Circle implements Shape {
 
   @Override
   public void draw() {
      System.out.println("Shape: Circle");
   }
}
//继承接口的抽象装饰类
public abstract class ShapeDecorator implements Shape {
   protected Shape decoratedShape;
 
   public ShapeDecorator(Shape decoratedShape){
      this.decoratedShape = decoratedShape;
   }
 
   public void draw(){
      decoratedShape.draw();
   }  
}
//继承抽象装饰的实现
public class RedShapeDecorator extends ShapeDecorator {
 
   public RedShapeDecorator(Shape decoratedShape) {
      super(decoratedShape);     
   }
 
   @Override
   public void draw() {
      decoratedShape.draw();         
      setRedBorder(decoratedShape);//扩展功能
   }
 
   private void setRedBorder(Shape decoratedShape){
      System.out.println("Border Color: Red");
   }
}
//Client
public class DecoratorPatternDemo {
   public static void main(String[] args) {
 
      Shape circle = new Circle();
      ShapeDecorator redCircle = new RedShapeDecorator(new Circle());
      ShapeDecorator redRectangle = new RedShapeDecorator(new Rectangle());
      //Shape redCircle = new RedShapeDecorator(new Circle());
      //Shape redRectangle = new RedShapeDecorator(new Rectangle());
      System.out.println("Circle with normal border");
      circle.draw();
 
      System.out.println("\nCircle of red border");
      redCircle.draw();
 
      System.out.println("\nRectangle of red border");
      redRectangle.draw();
   }
}
/*
Circle with normal border
Shape: Circle

Circle of red border
Shape: Circle
Border Color: Red

Rectangle of red border
Shape: Rectangle
Border Color: Red
*/