What's the difference between Interface Map and Mediation Module?

Question

What is the difference between Interface Map and Mediation Module in terms of IBM WID?

Answer 1

An Interface Map just joins together two interfaces. In essence this allows you to map data types from the different interfaces and it also can allow you to "map" (though this is done under the covers) the protocols between them. However if you have an error anywhere in between this maping you cannot (automatically) handle it, and you cannot map back to the return fault (at least easily). Plus you cannot do service routing/mediation. It is just a simple map between the two.

A Mediation Module allows you to do so much more. If you need to route a message to more than one service, or if you need to route to different services based on message content or metadata in the message headers, then you want a mediation module. If you need to do anything with security or auditing or logging, you want a mediation module. If you intend to create a service gateway pattern or hook up to a UDDI registry where your services are located (again, dynamic service lookup) you want a mediation module. You can also gain more on the side of error handling (retries, store and forward, route to a different service, map back to the service fault and return it, compensation for failed transaction, etc.)

In short, an interface map is for something more simple where you do not do any error handling and cannot recover. A mediation module is for when you need to handle a few more things between the service requester an the service provider.