Decorator Pattern

Definition

装饰者模式

//Drink.java
public abstract class Drink {
    public String description;
    private float price  = 0.0f;

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public float getPrice() {
        return price;
    }

    public void setPrice(float price) {
        this.price = price;
    }

    public abstract float cost();
}

//Coffee.java
public class Coffee extends Drink{
    @Override
    public float cost() {
        return super.getPrice();
    }
}

//Espresso.java
public class Espresso extends Coffee {
    public Espresso(){
        setDescription("Italy Coffee");
        setPrice(6.0f);
    }
}

//LongBlack.java
public class LongBlack extends Coffee {
    public LongBlack(){
        setDescription("Long Black");
        setPrice(5.0f);
    }
}

//ShortBlack.java
public class ShortBlack  extends Coffee{
   public ShortBlack(){
       setDescription("Short Black");
       setPrice(4.0f);
   }
}

//Chocolate.java
public class Decorator extends Drink {
    private Drink obj;

    public Decorator(Drink obj){
        this.obj = obj;
    }

    @Override
    public float cost() {
        // getPrice这里是调料的价格
        return super.getPrice() + obj.cost();
    }

    @Override
    public String getDescription() {
        return super.getDescription() +" " + super.getPrice() + " && " + obj.getDescription();
    }
}

//Chocolate.java
public class Chocolate extends Decorator {
    public Chocolate(Drink obj){
        super(obj);
        setDescription("Chocolate");
        setPrice(3.0f);
    }
}

//Milk.java
public class Milk extends Decorator {
    public Milk(Drink obj){
        super(obj);
        setDescription("Milk");
        setPrice(2.0f);
    }
}

//Soy.java
public class Soy extends Decorator {
    public Soy(Drink obj){
        super(obj);
        setDescription("Soy");
        setPrice(1.5f);
    }
}

在JDK中的应用：IO的设计

Decorator Pattern

原文：https://www.cnblogs.com/nedrain/p/13198766.html