软件设计策略模式

旅行方式的选择
旅游的出行方式有乘坐飞机旅行、乘火车旅行和自行车游，不同的旅游方式有不同的实现过程，客户可以根据自己的需要选择一种合适的旅行方式。

类图

Java

package rjsj.no23;

public class BicycleStrategy implements TravelStrategy{
    @Override
    public void travel() {
        System.out.println("骑自行车旅游");
    }
}

package rjsj.no23;

public class Client {
    public static void main(String[] args) {
        Traveler traveler = new Traveler();

        System.out.println("旅游开始！");
        TravelStrategy travelStrategy = new TrainStrategy();
        traveler.setTravelStrategy(travelStrategy);
        traveler.travel();
        System.out.println("**************************************************");
        System.out.println("旅游开始！");
        travelStrategy = new AirplaneStrategy();
        traveler.setTravelStrategy(travelStrategy);
        traveler.travel();
        System.out.println("**************************************************");
        System.out.println("旅游开始！");
        travelStrategy = new BicycleStrategy();
        traveler.setTravelStrategy(travelStrategy);
        traveler.travel();
        System.out.println("**************************************************");
    }
}

package rjsj.no23;

public class TrainStrategy implements TravelStrategy{
    @Override
    public void travel() {
        System.out.println("坐火车旅游");
    }
}

package rjsj.no23;

public class Traveler {
    private TravelStrategy travelStrategy;

    public void setTravelStrategy(TravelStrategy travelStrategy) {
        this.travelStrategy = travelStrategy;
    }

    public void travel(){
        travelStrategy.travel();
    }
}

package rjsj.no23;

public interface TravelStrategy {
    void travel();
}

package rjsj.no23;

public class AirplaneStrategy implements TravelStrategy{
    @Override
    public void travel() {
        System.out.println("乘坐飞机旅游");
    }
}

C++

#include<iostream>
using namespace std;
class TravelStrategy {
public:
    virtual void travel()=0;
};
class Person {
private:
    TravelStrategy *strategy;
public:
    void setStrategy(TravelStrategy *strategy) {
        this->strategy=strategy;
    }
    void travel() {
        this->strategy->travel();
    }
};
class TrainStrategy : public TravelStrategy{
public:
    void travel() {
        cout<<"坐火车"<<endl;
    }
};
class BicycleStrategy : public TravelStrategy{
public:
    void travel() {
        cout<<"骑自行车"<<endl;
    }
};
class AirplaneStrategy: public TravelStrategy{
public:
    void travel() {
        cout<<"坐飞机"<<endl;
    }
};
int main(){
        Person *pr=new Person();

        cout<<"旅游开始，请选择交通工具："<<endl;
        TravelStrategy *strategy=new TrainStrategy();
        pr->setStrategy(strategy);
        pr->travel();
        cout<<"****************************************"<<endl;

        cout<<"旅游开始，请选择交通工具："<<endl;
        TravelStrategy *strategy2=new BicycleStrategy();
        pr->setStrategy(strategy2);
        pr->travel();
        cout<<"****************************************"<<endl;

        cout<<"旅游开始，请选择交通工具："<<endl;
        TravelStrategy *strategy3=new AirplaneStrategy();
        pr->setStrategy(strategy3);
        pr->travel();
}

运行结果：