封装消息处理

一个消息可能会进行多种处理，把各种handle抽象出来，在我们需要某种handle的时候，将其加入到handle group进行集中处理

#include <iostream>#include <string>#include <vector>#include <boost/shared_ptr.hpp>typedef std::string Message;class MessageHandle{public:virtual void handle(Message& msg) = 0;virtual ~MessageHandle() { }};class Encrypt : public MessageHandle{public:virtual void handle(Message& msg){std::cout << "encrypt:" << msg << std::endl;}};class Decrypt : public MessageHandle{public:virtual void handle(Message& msg){std::cout << "decrypt:" << msg << std::endl;}};class Compress : public MessageHandle{public:virtual void handle(Message& msg){std::cout << "compress:" << msg << std::endl;}};class Decompress : public MessageHandle{public:virtual void handle(Message& msg){std::cout << "decompress:" << msg << std::endl;}};typedef boost::shared_ptr<MessageHandle> MessageHandlePtr;class MessageHandleGroup{public:void add(MessageHandlePtr messageHandlePtr){messageHandlePtrGroup_.push_back(messageHandlePtr);}void execute(Message &msg){std::vector<MessageHandlePtr>::iterator iter = messageHandlePtrGroup_.begin();for (; iter!=messageHandlePtrGroup_.end(); ++iter){(*iter)->handle(msg);}}private:std::vector<MessageHandlePtr> messageHandlePtrGroup_;};int main(void){Message msg("hello, world!");MessageHandleGroup messageHandleGroup;messageHandleGroup.add(MessageHandlePtr(new Encrypt()));messageHandleGroup.add(MessageHandlePtr(new Decrypt()));messageHandleGroup.add(MessageHandlePtr(new Compress()));messageHandleGroup.add(MessageHandlePtr(new Decompress()));messageHandleGroup.execute(msg);system("pause");}