C# 3.0 Design Patterns

Pattern Comparison

A similarity between the Chain of Responsibility and the Command patterns is that they decouple senders and receivers, thus improving the layering and reusability of a system. The Chain of Responsibility pattern supports decoupling by passing a request between potential receivers, whereas the Command pattern supports using a command object to encapsulate a request. The implementation issues are described in Table 8-1.

Table 8-1. Comparison of the Chain of Responsibility and Command patterns

Â	Chain of Responsibility	Command
Client creates	Handler objects	Command objects
Different kinds of	Handler classes at different levels	Command classes and Receiver classes
Client can work with	Multiple handlers	Different receivers
Client calls	Handler objects	Receiver objects
Work is done in	HandleRequest, in a handler	Action, in a receiver
Decisions based on	Limits in handlers	Routing in commands
Deals with unimplementable requests	Yes	Yes