Chain of Responsibility pattern avoids coupling the sender of a request to its receiver by giving more than one object a chance to handle the request. The pattern chains the receiving objects and passes the request along the chain until an object handles it. It has a behavioral purpose and deals with relationships between objects.
- more than one object may handle a request, and the handler should be ascertained automatically
- you want to issue a request to one of several objects without specifying the receiver explicitly
- the set of objects that can handle a request should be specified dynamically