1.Chain of Responsibility模式:将可能处理一个请求的对象链接成一个链，并将请求在这个链上传递，直到有对象处理该请求（可能需要提供一个默认处理所有请求的类，例如MFC中的CwinApp类）。
2.Chain of Responsibility Pattern 结构图
3.实现
1 #ifndef _HANDLE_H_ 2 #define _HANDLE_H_ 3 4 class Handle 5 { 6 public: 7 virtual ~Handle(); 8 virtual void HandleRequest() = 0; 9 void SetSuccessor(Handle* succ); 10 Handle* GetSuccessor(); 11 12 protected: 13 Handle(); 14 Handle(Handle* succ); 15 16 private: 17 Handle* _succ; 18 }; 19 20 class ConcreteHandleA:public Handle 21 { 22 public: 23 ConcreteHandleA(); 24 ~ConcreteHandleA(); 25 ConcreteHandleA(Handle* succ); 26 void HandleRequest(); 27 28 protected: 29 private: 30 }; 31 32 class ConcreteHandleB:public Handle 33 { 34 public: 35 ConcreteHandleB(); 36 ~ConcreteHandleB(); 37 ConcreteHandleB(Handle* succ); 38 void HandleRequest(); 39 protected: 40 private: 41 }; 42 43 #endif
1 #include "Handle.h" 2 #include <iostream> 3 using namespace std; 4 5 Handle::Handle() 6 { 7 _succ = 0; 8 } 9 Handle::~Handle() 10 { 11 delete _succ; 12 } 13 Handle::Handle(Handle* succ) 14 { 15 this->_succ = succ; 16 } 17 void Handle::SetSuccessor(Handle* succ) 18 { 19 _succ = succ; 20 } 21 Handle* Handle::GetSuccessor() 22 { 23 return _succ; 24 } 25 void Handle::HandleRequest() 26 { 27 28 } 29 ConcreteHandleA::ConcreteHandleA() 30 { 31 32 } 33 ConcreteHandleA::ConcreteHandleA(Handle* succ):Handle(succ) 34 { 35 36 } 37 ConcreteHandleA::~ConcreteHandleA() 38 { 39 40 } 41 void ConcreteHandleA::HandleRequest() 42 { 43 if (this->GetSuccessor() != 0) 44 { 45 cout<<"ConcreteHandleA 我把处理权给后继节点....."<<endl; 46 this->GetSuccessor()->HandleRequest(); 47 } 48 else 49 { 50 cout<<"ConcreteHandleA 没有后继了，我必须自己处理...."<<endl; 51 } 52 } 53 ConcreteHandleB::ConcreteHandleB() 54 { 55 56 } 57 ConcreteHandleB::ConcreteHandleB(Handle* succ):Handle(succ) 58 { 59 60 } 61 ConcreteHandleB::~ConcreteHandleB() 62 { 63 64 } 65 void ConcreteHandleB::HandleRequest() 66 { 67 if (this->GetSuccessor() != 0) 68 { 69 cout<<"ConcreteHandleB 我把处理权给后继节点....."<<endl; 70 this->GetSuccessor()->HandleRequest(); 71 } 72 else 73 { 74 cout<<"ConcreteHandleB 没有后继了，我必须自己处理...."<<endl; 75 } 76 }
1 #include "Handle.h" 2 #include <iostream> 3 using namespace std; 4 5 int main(int argc,char* argv[]) 6 { 7 Handle* h1 = new ConcreteHandleA(); 8 Handle* h2 = new ConcreteHandleB(); 9 h1->SetSuccessor(h2); 10 h1->HandleRequest(); 11 return 0; 12 }