设计模式之责任链模式

#include <iostream>

using namespace std;

class Handler
{
public:
    virtual void HandleRequest() = 0;
     void setNextHandler(Handler *nextHandler)
     {
        this->nextHandler=nextHandler;
     }
protected:
     Handler *nextHandler;
};


class ConcreteHanderA:public Handler
{
public:
    virtual void HandleRequest()
    {
        cout<<"ConcreteHanderA HandleRequest "<<endl;
        if(nextHandler != NULL)
        {
            nextHandler->HandleRequest();
        }
    }
};


class ConcreteHanderB:public Handler
{
public:
    virtual void HandleRequest()
    {
        cout<<"ConcreteHanderB HandleRequest "<<endl;
        if(nextHandler != NULL)
        {
            nextHandler->HandleRequest();
        }
    }
};

class ConcreteHanderC:public Handler
{
public:
    virtual void HandleRequest()
    {
       cout<<"ConcreteHanderC HandleRequest "<<endl;
       if(nextHandler != NULL)
       {
           nextHandler->HandleRequest();
       }
    }
};

int main()
{
    Handler * handlerA = new ConcreteHanderA();
    Handler * handlerB = new ConcreteHanderB();
    Handler * handlerC = new ConcreteHanderC();
    handlerA->setNextHandler(handlerC);
    handlerC->setNextHandler(handlerB);

    handlerA->HandleRequest();
    return 0;
}