message driven vs. event driven approaches to application integration

Question

Hello,

I was wondering if there is a clear distinction between message driven and event driven environments when we refer to SOA or middleware and generally in cases of application and enterprise integration. I understand that a user interface resembles an event driven model where our system intercepts action by the user.

Also it is clear that messaging supports systems based on publish/subscribe, sychronous or asynchronous communication, transactions etc.

But is there a difference in the middleware/soa/application intergration context? (architecture level). I am trying to consult sources such wikipedia (here, and here), but I am still somewhat confused. When should a developer prefer one solution over the other?

Are there examples or cases where one approach makes more sense than the other? Or any comprehensive resources and guides to implementing each one?

Many thanks for any insight.

Answer 1

Short answer to "is there a clear distinction" would be "no".

The terms are not quite interchangeable, but imply the same basic architecture - specifically that you will be triggering off of events or messages.

The first article you reference is about the low-level plumbing, the MOM or pub-sub "bus" that transports the messages on your behalf. The event-driven architecture is what you build on top of that framework.

The term event-driven, while also applying to GUI code, is not really at the same level of abstraction. In that case, it is a pattern in-the-small compared to building your entire enterprise along message/event driven lines.