However, a Message Channel (60) provided by a messaging infrastructure can be quite heavyweight if all components can in fact reside on the same machine. Using a simple in-memory queue to implement the pipes would be much more efficient. Therefore, it is useful to design the components so that they communicate with an abstract pipe interface. The implementation of that interface can then be swapped out to use a Message Channel (60) or an alternative implementation such as an in-memory queue. The Messaging Gateway (468) describes how to design components for this flexibility.
