Java行为型设计模式之策略模式详解

/**
 * 折扣
 */
public interface Discount {
    /**
     * 计算价格
     * @param money
     * @return
     */
    public int calculate(int money);
}
/**
 * 满减策略
 * 需要满200
 */
public class FullDiscount implements Discount{
    @Override
    public int calculate(int money) {
        if (money>200){
            System.out.println("符合满减策略，进行满减");
            return money - 30;
        }
        return money;
    }
}
/**
 * 假日折扣
 * 需要大于100
 */
public class HolidayDiscount implements Discount{
    @Override
    public int calculate(int money) {
        if (money > 100){
            return money - 10;
        }
        return money;
    }
}
/**
 * 新用户减免
 * 但是也需要大于100
 */
public class NewerDiscount implements Discount{
    @Override
    public int calculate(int money) {
        if (money>100){
            return money-20;
        }
        return money;
    }
}
/**
 * 第二单8折优惠
 */
public class SecondDiscount implements Discount {
    @Override
    public int calculate(int money) {
        Double balance =  money * 0.8;
        return balance.intValue();
    }
}
 public static void main(String[] args) {
        List<Fruit> products = new ArrayList();
        products.add(StaticFactory.getFruitApple());
        products.add(StaticFactory.getFruitBanana());
        products.add(StaticFactory.getFruitOrange());
        ShoppingCart cart = new CartShopping(products);
        /*注入优惠方案*/
        cart.setDiscount(new FullDiscount());
        cart.submitOrder();
    }