二、商品促销-策略模式

一、简单工厂实现

现金收费抽象类:

package ch02strategy;

abstract class CashSuper {

public abstract double acceptCash(double money);

}

正常收费子类：

package ch02strategy;

public class CashNormal extends CashSuper {

@Override
public double acceptCash(double money) {
// TODO Auto-generated method stub
return money;
    }

}

打折收费子类：

package ch02strategy;

public class CashRebate extends CashSuper {

private double moneyRebate = 1d;

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

@Override
public double acceptCash(double money) {
// TODO Auto-generated method stub
return money * moneyRebate;
    }

}

返利收费子类：

package ch02strategy;

public class CashReturn extends CashSuper {

private double moneyCondition = 0.0d;
private double moneyReturn = 0.0d;

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

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

}

现金收费工厂类：

package ch02strategy;

public class CashFactory {

public static CashSuper createCashAccept(String type){
        CashSuper cs = null;
char charType = type.charAt(0);
//char charType = (char)type;
switch (charType){
case 'n':
            cs = new CashNormal();
break;
case 'r':
            CashReturn cr1 = new CashReturn("300","100");
            cs = cr1;
break;
case '8':
            CashRebate cr2 = new CashRebate("0.8");
            cs = cr2;
break;

        }
return cs;
    }

}

---

二、策略模式

策略模式（Strategy）：它定义了算法家族，分别封装起来，让它们之间可以互相替换，此模式让算法的变化，不会影响到使用算法的客户（客户端）。

class Context {
    Strategy strategy;
public Context(Strategy strategy) {
this.strategy = strategy;
    }
public void ContextInterface() {
        strategy.AlgorithmInterface();
    }
}

策略与简单工厂结合：

package ch02strategy;

public class CashContext {

    CashSuper cs = null;

public CashContext(String type){

char charType = type.charAt(0);
//char charType = (char)type;
switch (charType){
case 'n':
            cs = new CashNormal();
break;
case 'r':
            CashReturn cr1 = new CashReturn("300","100");
            cs = cr1;
break;
case '8':
            CashRebate cr2 = new CashRebate("0.8");
            cs = cr2;
break;

        }
    }

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

}

---

三、策略模式解析

switch语句看着总是让人不爽啊。。。