策略模式UML图形及代码

参考：http://blog.****.net/lovelion/article/details/17517213 

//电影票类：环境类  
class MovieTicket {  
    private double price;  
    private Discount discount; //维持一个对抽象折扣类的引用  
  
    public void setPrice(double price) {  
        this.price = price;  
    }  
  
    //注入一个折扣类对象  
    public void setDiscount(Discount discount) {  
        this.discount = discount;  
    }  
  
    public double getPrice() {  
        //调用折扣类的折扣价计算方法  
        return discount.calculate(this.price);  
    }  
}  
  
//折扣类：抽象策略类  
interface Discount {  
    public double calculate(double price);  
}  
  
//学生票折扣类：具体策略类  
class StudentDiscount implements Discount {  
    public double calculate(double price) {  
        System.out.println("学生票：");  
        return price * 0.8;  
    }  
}   
  
//儿童票折扣类：具体策略类  
class ChildrenDiscount implements Discount {  
    public double calculate(double price) {  
        System.out.println("儿童票：");  
        return price - 10;  
    }  
}   
  
//VIP会员票折扣类：具体策略类  
class VIPDiscount implements Discount {  
    public double calculate(double price) {  
        System.out.println("VIP票：");  
        System.out.println("增加积分！");  
        return price * 0.5;  
    }  
}