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【设计模式】【策略模式 打折算法】
/**
* Description:
* <br/>网站: <a href="https://www.crazyit.org">疯狂Java联盟</a>
* <br/>Copyright (C), 2001-2012, Yeeku.H.Lee
* <br/>This program is protected by copyright laws.
* <br/>Program Name:
* <br/>Date:
* @author Yeeku.H.Lee kongyeeku@163.com
* @version 1.0
*/
public interface DiscountStrategy
{
//定义一个用于计算打折价的方法
double getDiscount(double originPrice);
}
/**
* Description:
* <br/>网站: <a href="https://www.crazyit.org">疯狂Java联盟</a>
* <br/>Copyright (C), 2001-2012, Yeeku.H.Lee
* <br/>This program is protected by copyright laws.
* <br/>Program Name:
* <br/>Date:
* @author Yeeku.H.Lee kongyeeku@163.com
* @version 1.0
*/
//实现DiscountStrategy接口，实现对VIP打折的算法
public class VipDiscount
implements DiscountStrategy
{
//重写getDiscount()方法，提供VIP打折算法
public double getDiscount(double originPrice)
{
System.out.println("使用VIP折扣...");
return originPrice * 0.5;
}
}
/**
* Description:
* <br/>网站: <a href="https://www.crazyit.org">疯狂Java联盟</a>
* <br/>Copyright (C), 2001-2012, Yeeku.H.Lee
* <br/>This program is protected by copyright laws.
* <br/>Program Name:
* <br/>Date:
* @author Yeeku.H.Lee kongyeeku@163.com
* @version 1.0
*/
public class OldDiscount
implements DiscountStrategy
{
//重写getDiscount()方法，提供旧书打折算法
public double getDiscount(double originPrice)
{
System.out.println("使用旧书折扣...");
return originPrice * 0.7;
}
}
/**
* Description:
* <br/>网站: <a href="https://www.crazyit.org">疯狂Java联盟</a>
* <br/>Copyright (C), 2001-2012, Yeeku.H.Lee
* <br/>This program is protected by copyright laws.
* <br/>Program Name:
* <br/>Date:
* @author Yeeku.H.Lee kongyeeku@163.com
* @version 1.0
*/
public class DiscountContext
{
//组合一个DiscountStrategy对象
private DiscountStrategy strategy;
//构造器，传入一个DiscountStrategy对象
public DiscountContext(DiscountStrategy strategy)
{
this.strategy = strategy;
}
//根据实际所使用的DiscountStrategy对象得到折扣价
public double getDiscountPrice(double price)
{
//如果strategy为null，系统自动选择OldDiscount类
if (strategy == null)
{
strategy = new OldDiscount();
}
return this.strategy.getDiscount(price);
}
//提供切换算法的方法
public void changeDiscount(DiscountStrategy strategy)
{
this.strategy = strategy;
}
}
/**
* Description:
* <br/>网站: <a href="https://www.crazyit.org">疯狂Java联盟</a>
* <br/>Copyright (C), 2001-2012, Yeeku.H.Lee
* <br/>This program is protected by copyright laws.
* <br/>Program Name:
* <br/>Date:
* @author Yeeku.H.Lee kongyeeku@163.com
* @version 1.0
*/
public class StrategyTest
{
public static void main(String[] args)
{
//客户端没有选择打折策略类
DiscountContext dc = new DiscountContext(null);
double price1 = 79;
//使用默认的打折策略
System.out.println("79元的书默认打折后的价格是："
+ dc.getDiscountPrice(price1));
//客户端选择合适的VIP打折策略
dc.changeDiscount(new VipDiscount());
double price2 = 89;
//使用VIP打折得到打折价格
System.out.println("89元的书对VIP用户的价格是："
+ dc.getDiscountPrice(price2));
}
}
最后更新：2017-04-04 07:03:38