设计模式-- 责任链模式

    责任链的原理google多的事
   直接上自己的理解和类图代码：
   

代码：

// LineTree.cpp : Defines the entry point for the console application.
//责任链模式
//

#include "stdafx.h"
#include <iostream>
#include <list>

class Handler
{
public:
    Handler(int seriNum){
        m_num = seriNum;
    }
    virtual ~Handler(){}

    virtual void handleRequest(int seriNum) = 0;
public:
    void setNextHandler(Handler *tmp)
    {
        m_nextHandler = tmp;
    }
protected:
    Handler* getNextHandler()
    {
        return m_nextHandler;
    }
protected:
    int m_num{ 0 };
private:
    Handler *m_nextHandler{nullptr};

};

class firstHandler : public Handler{
public:
    firstHandler(int seriNum) : Handler(seriNum)
    {

    }
    ~firstHandler()
    {

    }
    virtual void handleRequest(int seriNum)
    {
        if (seriNum == m_num)
        {
            std::cout << "first handle" << std::endl;
        }
        else
        {
            Handler* next = getNextHandler();
            if (next == nullptr)
            {
                std::cout << "It's over" << std::endl;
                return;
            }
            next->handleRequest(seriNum);
        }
    }
};

class secondHandler : public Handler{
public:
    secondHandler(int seriNum) : Handler(seriNum)
    {

    }
    ~secondHandler()
    {

    }
    virtual void handleRequest(int seriNum)
    {
        if (seriNum == m_num)
        {
            std::cout << "second handle" << std::endl;
        }
        else
        {
            Handler* next = getNextHandler();
            if (next == nullptr)
            {
                std::cout << "It's over" << std::endl;
                return;
            }
            next->handleRequest(seriNum);
        }
    }
};


class ThirdHandler : public Handler{
public:
    ThirdHandler(int seriNum) : Handler(seriNum)
    {

    }
    ~ThirdHandler()
    {

    }
    virtual void handleRequest(int seriNum)
    {
        if (seriNum == m_num)
        {
            std::cout << "Third handle" << std::endl;
        }
        else
        {
            Handler* next = getNextHandler();
            if (next == nullptr)
            {
                std::cout << "It's over" << std::endl;
                return;
            }
            next->handleRequest(seriNum);
        }
    }
};

int _tmain(int argc, _TCHAR* argv[])
{

    //先创建三个具体的处理类
    Handler *first = new firstHandler(1);
    Handler *second = new secondHandler(2);
    Handler *third = new ThirdHandler(3);

    first->setNextHandler(second);
    second->setNextHandler(third);
    third->setNextHandler(nullptr);

    Handler *startHandler = first;
    startHandler->handleRequest(1);
    return 0;
}