Anemic Domain Model

I was reading an article by Sean Corfield in Fusion Authority today. I have read this article before, but my brain was not ready to grok it, today, it grokked.

The main concept is that too often we load up bus. logic in the service object instead of the bean or value object where it belongs. If you think critically on this, it makes sense that since the data and methods of an object are encapsulated into the value or bean object, so too should the bus. rules around it.

The anemic model is one where the value beans are just containers with state and getter and setter methods - not much else, the bus. rules are stored in the service object.

Sean makes a good point that many of our web applications are getting record sets, presenting in a collection, hiding detail, proving details about one record when requested, not alot of bus. logic to fill up our value beans. But, a good candidate is validation logic when dealing with single or groups of recs, rather than putting that logic in the service, leave it in the value bean - let it live along with the data and methods that it works on.

I recently completed grokking why bus. logic should be in the service and not the listener (model layer, not the application). I supplemented my understanding by going through a few of the older listeners and moving bus. logic out of and into related service object. Perhaps i will iterate again, moving small amount of logic from the services into the beans.

Lets turn those anemic value objects into rich domain objects!