策略模式主要是为了封装变化,体现在Context类中.
策略模式+工厂模式(如下Context类),可以更好的隔离客户端.(减少了耦合嘛)
策略模式解析
策略模式是定义一系列算法的方法,从概念上看,所有这些算法完成的都是相同的工作,只是实现不同,它可以以相同的方式调用所有的算法,减少了各种算法类与使用算法类之间的耦合.
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| package strategy;
public abstract class Strategy {
public abstract double acceptCash(double money);
}
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| package strategy;
public class Normal extends Strategy {
public double acceptCash(double money) {
return money;
}
}
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| package strategy;
public class Rate extends Strategy {
private double rate = 0.9;
public double acceptCash(double money) {
return rate * money;
}
}
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| package strategy;
public class Context {
private Strategy strategy;
public Context(Type type) {
switch (type) {
case NORMAL:
strategy = new Normal();
break;
case RATE:
strategy = new Rate();
break;
}
}
public double getResult(double money) {
return strategy.acceptCash(money);
}
enum Type {NORMAL, RATE, RETURN}
}
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| package strategy;
public class Main {
public static void main(String[] args) {
Context context = null;
context = new Context(Context.Type.NORMAL);
double accept = context.getResult(100);
System.out.println(accept);
context = new Context(Context.Type.RATE);
accept = context.getResult(100);
System.out.println(accept);
}
}
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