装饰者模式

Product.java

public interface Product {

    public int money();
}

public interface Product {

	public int money();
}

Coffee.java

public class Coffee implements Product {

    public int money() {
        return 10;
    }

}

public class Coffee implements Product {

	public int money() {
		return 10;
	}

}

Sugar.java

public class Sugar implements Product {

    private Product p; //组合

    public Sugar(Product p){
        this.p = p;
    }

    public int money() {
        return p.money()+5;
    }

}

public class Sugar implements Product {

	private Product p; //组合
	
	public Sugar(Product p){
		this.p = p;
	}
	
	public int money() {
		return p.money()+5;
	}

}

Milk.java

public class Milk implements Product {

    private Product p;

    public Milk(Product p){
        this.p = p;
    }
    public int money() {
        return p.money()+10;
    }

}

public class Milk implements Product {

	private Product p;
	
	public Milk(Product p){
		this.p = p;
	}
	public int money() {
		return p.money()+10;
	}

}

Main.java

public class Main {

    public static void main(String[] args) {

        //咖啡的价格
        Coffee coffee = new Coffee();
        System.out.println(coffee.money());

        //加糖咖啡的价格
        Sugar s = new Sugar(coffee);
        System.out.println(s.money());
//
        //牛奶咖啡的价格
        Milk m = new Milk(coffee);
        System.out.println(m.money());

        //牛奶加糖咖啡
        Milk milk = new Milk(new Sugar(new Coffee()));
        System.out.println(milk.money());
    }

}