策略模式

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#策略模式

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本文介绍了一种使用策略模式实现的灵活收费系统。通过定义一系列算法，并将每个算法封装起来，使它们可以互相替换，系统能够在运行时选择并使用合适的算法。文章详细解释了正常收费、打折收费和返利收费三种策略的具体实现。

**
 * @Author: subd
 * @Date: 2019/9/11 8:08
 * 策略模式
 */
public class StrategyMode {
    /**
     * 现金收费抽象类
     */
    public static abstract class CashSuper {
        public abstract double acceptCash(double money);
    }

    /**
     * 正常收费子类
     */
    public static class CashNormal extends CashSuper {
        @Override
        public double acceptCash(double money) {
            return money;
        }
    }

    /**
     * 打折收费子类
     */
    public static class CashRebate extends CashSuper {
        private double moneyRebate = 1d;

        public CashRebate(String moneyRebate) {
            this.moneyRebate = Double.valueOf(moneyRebate);
        }

        @Override
        public double acceptCash(double money) {
            return money * moneyRebate;
        }
    }

    /**
     * 返利收费子类
     */
    public static class CashReturn extends CashSuper {
        private double moneyCondition = 0.0d;
        private double moneyReturn = 0.0d;

        public CashReturn(String moneyCondition, String moneyReturn) {
            this.moneyCondition = Double.valueOf(moneyCondition);
            this.moneyReturn = Double.valueOf(moneyReturn);
        }

        @Override
        public double acceptCash(double money) {
            double result = money;
            if (money >= moneyCondition) {
                result = money - Math.floor(money / moneyCondition) * moneyReturn;
            }
            return result;
        }
    }

    public static class CashContext {
        private CashSuper cs;

        public CashContext(String type) {
            switch (type) {
                case "正常收费":
                    cs = new CashNormal();
                    break;
                case "满300返100":
                    CashReturn cr1 = new CashReturn("300", "100");
                    cs = cr1;
                    break;
                case "打8折":
                    CashRebate cr2 = new CashRebate("0.8");
                    cs = cr2;
                    break;
            }
        }

        public double GetResult(double money) {
            return cs.acceptCash(money);
        }
    }

    public static class Client {
        /**
         * 用于总计
         */
        double total = 0.0d;

        private void btnOkClick(String type, double price, int num) {
            CashContext cc = new CashContext(type);
            double totalPrices = 0.0d;
            totalPrices = cc.GetResult(price * num);
            total = total + totalPrices;
            System.out.println("单价: " + price + " 数量: " + num + " 合计: " + total);
        }
    }

    public static void main(String[] args) {
        Client client = new Client();
        client.btnOkClick("正常收费", 333, 2);
        client.btnOkClick("满300返100", 300, 10);
        client.btnOkClick("打8折", 500, 4);
    }
}