Requested Interface

This paper introduces the Requested Interface Pattern which describes ways to implement truly independent software components that can be plugged together as needed in order to make reuse more attractive than reimplementation. It encourages components to delegate subtasks to collaborating servers so that they can be adapted to a new context by simply exchanging those subtask servers. The delegating objects must specify minimal and abstract requested interfaces that describe the subtasks independently of existing server interfaces. An adaption layer mediates between the requested interface of a client and the offered interface of a server implementing the subtask.