Responsibility chain Model

1. Definition

Enables multiple objects to have the opportunity to process the request, thereby avoiding the coupling between the sender and the recipient of the request, connecting the objects to a chain, and passing the request along the chain until an object has processed it. The focus of the chain of responsibility is on the "chain", by a chain to handle similar requests in the chain to determine who will handle the request, and return the corresponding results.

2. Code implementation

     Public Abstract classHandler {PrivateHandler _nexthandler;  PublicResponse handlemessage (Request request) {Response Response=NULL; Determine if it is your own level of processingif(Request. Getrequestlevel (). Equals ( This. Gethandlerlevel ())) {Response=Echo (Request); }            Else            {
does not belong to its own processing level, to determine whether there is a next processorif(_nexthandler! =NULL) {Response=_nexthandler.handlemessage (Request); }            }            returnResponse }
Set the next processor Public voidSetnexthandler (Handler Handler) {_nexthandler=handler; }//Each processor must implement processing tasksprotected AbstractResponse Echo (Request request); Each processor has a processing levelprotected AbstractLevel gethandlerlevel (); }     Public classConcretehandler1:handler {/// <summary>        ///define your own business logic/// </summary>        /// <param name= "Request" ></param>        /// <returns></returns>        protected OverrideResponse Echo (Request request) {Throw Newnotimplementedexception (); }        /// <summary>        ///set your own processing level/// </summary>        /// <returns></returns>        protected OverrideLevel Gethandlerlevel () {Throw Newnotimplementedexception (); }    }     Public classConcretehandler2:handler {/// <summary>        ///define your own business logic/// </summary>        /// <param name= "Request" ></param>        /// <returns></returns>        protected OverrideResponse Echo (Request request) {Throw Newnotimplementedexception (); }        /// <summary>        ///set your own processing level/// </summary>        /// <returns></returns>        protected OverrideLevel Gethandlerlevel () {Throw Newnotimplementedexception (); }    }     Public classConcretehandler3:handler {/// <summary>        ///define your own business logic/// </summary>        /// <param name= "Request" ></param>        /// <returns></returns>        protected OverrideResponse Echo (Request request) {Throw Newnotimplementedexception (); }        /// <summary>        ///set your own processing level/// </summary>        /// <returns></returns>        protected OverrideLevel Gethandlerlevel () {Throw Newnotimplementedexception (); }    }

    /// <summary>    ///request and processing levels/// </summary>     Public classLevel {}/// <summary>    ///Define a request/// </summary>     Public classRequest { PublicLevel Getrequestlevel () {return NULL; }    }    /// <summary>    ///data returned by the processor/// </summary>     Public classResponse {}

    /// <summary>    ///Scene Class/// </summary>    classProgram {Private Static voidMain (string[] args) {
Declares all processing nodes Handler Handler1=NewConcreteHandler1 (); Handler Handler2=NewConcreteHandler2 (); Handler Handler3=NewConcreteHandler3 (); Sets the sequence of stages in the chain handler1.            Setnexthandler (Handler2); Handler2.            Setnexthandler (HANDLER3); Submit the request and return the result handler1. Handlemessage (NewRequest ());        Console.readkey (); }    }

Responsibility chain Model