責任鏈模式

                   責任鏈模式（Chain of Responsibility）的目標是使多個對象都有機會處理請求，從而避免請求的發送者和接收者之間的耦合關係。將這些對象連成一條鏈，並沿着這條鏈傳遞請求，直到有一個對象處理它爲止。

              舉個例子。你到銀行去辦理業務，只是簡單的存個錢，也許ATM就解決你的問題。若是你是爲了交費用的，那等去櫃檯，但你倒是來諮詢金融產品的，會有專員接待你，事實上你是一個大客戶，經理就會把你請到他辦公室好好和你談談，就這樣。

               類圖的關係以下：

                   

                

 

                  代碼實現：

#ifndef BANKWORKER_H

#define BANKWORKER_H

#include <iostream>

using namespace std;

class BankWorker

{

public:

 BankWorker(int _standard, BankWorker *_pNext);

 virtual ~BankWorker();

 virtual void handle(int) = 0;

protected:

 int getStandard() const {return standard;}

 BankWorker* getNextWorker() const {return p_nextWorker;}

private:

 int standard;

 BankWorker *p_nextWorker;

};

#endif // BANKWORKER_H

 

#include "bankworker.h"

BankWorker::BankWorker(int _standard, BankWorker *_pNext):standard(_standard)

 ,p_nextWorker(_pNext)

{

}

BankWorker::~BankWorker()

{

 delete p_nextWorker;

 cout << "~~~\n";//可以幫助你瞭解析構的過稱，更好的掌握繼承

}

#ifndef ATM_H

#define ATM_H

#include "bankworker.h"

class ATM : public BankWorker

{

public:

 ATM(int _s,BankWorker *_p);

 ~ATM(){cout <<"ATM\n";}

 void handle(int client);

};

#endif // ATM_H

#include "atm.h"

ATM::ATM(int _s, BankWorker *_p):BankWorker(_s,_p)

{

}

void ATM::handle(int client)

{

 if (getStandard() > client) {

 cout << "ATM fall for you!\n";

 }

 else {

 if (getNextWorker() != NULL) {

 getNextWorker()->handle(client);

 }

 }

}

#ifndef COUNTERBOY_H

#define COUNTERBOY_H

#include "bankworker.h"

class Counterboy : public BankWorker

{

public:

 Counterboy(int _s,BankWorker *_p);

 ~Counterboy(){cout << "Counterboy\n";}

 void handle(int client);

};

#endif // COUNTERBOY_H

#include "counterboy.h"

Counterboy::Counterboy(int _s, BankWorker *_p):BankWorker(_s, _p)

{

}

void Counterboy::handle(int client)

{

 if (getStandard() > client) {

 cout << "Counterboy fall for you!";

 }

 else {

 if (getNextWorker() != NULL) {

 getNextWorker()->handle(client);

 }

 }

}

#ifndef MANAGER_H

#define MANAGER_H

#include "bankworker.h"

class Manager : public BankWorker

{

public:

 Manager(int _s = 0,BankWorker *_p = NULL);

 ~Manager(){cout << "manager\n";}

 void handle(int client);

};

#endif // MANAGER_H

#include "manager.h"

Manager::Manager(int _s, BankWorker *_p):BankWorker(_s, _p)

{

}

void Manager::handle(int client)

{

 cout << "I am Manager, I can do anything for you!" << '\n';

}

#include <iostream>

using namespace std;

#include "atm.h"

#include "counterboy.h"

#include "manager.h"

int main()

{

 Manager *p_m = new Manager();

 Counterboy *p_c = new Counterboy(10000,p_m);

 ATM *p_atm = new ATM(2000,p_c);

 p_atm->handle(30000);

 delete p_atm;

 return 0;

}

注：在此處只是以業務錢數的大小來分類，並且經理很牛，能解決一切問題，因此不會使請求得不到解決。