设计模式 Design Parttern ——责任链模式Chain of Responsibility

最新推荐文章于 2010-10-28 23:29:00 发布

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#设计模式 #header #class #linker #api #c

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本文介绍了一种设计模式——责任链模式，并通过一个具体的C++实现示例来展示其工作原理。责任链模式允许请求沿着处理者链传递，直到有一个处理者能够处理它为止。文章包含头文件定义、具体处理节点实现及链表处理过程。

设计模式 Design Parttern ——责任链Chain of Responsibility

http://blog.youkuaiyun.com/leeidea/

1:头文件

#ifndef _CHAIN_OF_RESONSIBILITY_H_VANEY_ #define _CHAIN_OF_RESONSIBILITY_H_VANEY_ #include <iostream> using namespace std; /****************************************************************** 名称：ChainofResponsibility.h 版本：1.00 描述：演示责任链模式的概念作者：vaney.li@gmail.com http://blog.youkuaiyun.com/leeidea 日期：2010年10月22日版权：vaney.li@gmail.com http://blog.youkuaiyun.com/leeide ******************************************************************/ /* 官方解释：The Chain of Responsibility pattern avoids coupling the sender of a request to the receiver. 我的理解：一个需要处理的事件过来后，丢给一个事件处理链，处理链的每个节点对应处理一类特定事件，事件经过该链表后就会被其中一个节点处理，当然也可以没有一个节点处理它我的应用：消息处理链 */ //抽象节点 class CHandler { public: CHandler() { next = 0; cout << "CHandler()" << endl; } virtual ~CHandler() { cout << "~CHandler()" << endl; } public: virtual int eat(int msg) = 0; CHandler* next; }; //具体处理事件节点 class CHandler1 : public CHandler { public: CHandler1() { cout << "CHandler1()" << endl; } virtual ~CHandler1() { cout << "~CHandler1()" << endl; } public: virtual int eat(int msg) { if(0 == msg) { cout << "CHandler1 eat msg" << endl; return 1; } else { cout << "CHandler1 pass msg" << endl; return 0; } } }; //具体处理事件节点2 class CHandler2 : public CHandler { public: CHandler2() { cout << "CHandler2()" << endl; } virtual ~CHandler2() { cout << "~CHandler2()" << endl; } public: virtual int eat(int msg) { if(1 == msg) { cout << "CHandler2 eat msg" << endl; return 1; } else { cout << "CHandler2 pass msg" << endl; return 0; } } }; //处理事件链 class CHandleLinker { CHandler* header; public: CHandleLinker() { header = 0; cout << "CHandleLinker()" << endl; } virtual ~CHandleLinker() { //增加释放节点代码 cout << "~CHandleLinker()" << endl; } public: virtual void AddNode(CHandler* node) { CHandler* storeheader = header; if(!header) { header = node; return; } if(node) { while(header->next) { header = header->next; } header->next = node; } header = storeheader; } virtual void process_msg(int msg) { CHandler* storeheader = header; while(storeheader) { if(storeheader->eat(msg)) { break; } else { storeheader = storeheader->next; } } } }; #define C_API extern "C" //用户 C_API int UsingCR(); #endif

2:源文件

#include "ChainofResponsibility.h" C_API int UsingCR() { CHandleLinker* linker = new CHandleLinker(); linker->AddNode(new CHandler1()); linker->AddNode(new CHandler2()); linker->AddNode(new CHandler2()); linker->process_msg(1); linker->process_msg(0); return 1; }

3:用户文件main.c

extern int UsingCR(); //系统默认入口 int _tmain(int argc, _TCHAR* argv[]) { return UsingCR(); }