Comments on: Injecting dependencies into a TransferObject

By: brian

brian — Thu, 10 Jan 2008 18:55:46 +0000

@Brian K – I hope the dynamic injector you sent Mark and Chris is released soon. One problem with these frameworks is staying on top of changes can be difficult… especially since I’m running BERs of everything here. Although this injectorObserver method works, it does feel a little funky to be doing a case/switch on the class name.

By: brian

brian — Thu, 10 Jan 2008 17:39:57 +0000

@Brian R – I initially agreed with you. I built my service layer very independent so nothing was too tightly coupled. However, having read that thread on the MG list and talking with Brian K, Sean and others, I can see the benefit of “smarter” beans. It certainly makes development easier but I also worry about dependencies.

Ultimately, if the getRegistrations() request is routed back through the service layer, then really all you’ve done is created a shortcut from the member bean to the service layer which is a convenience.

I still have some questions for Brian K and others that I’ll post to the MG listserv this morning before I go crazy.

By: Brian Rinaldi

Brian Rinaldi — Thu, 10 Jan 2008 17:03:47 +0000

I guess I see your point after giving it a little bit of thought. Perhaps its not such a bad design decision, though my gut still leans towards a user not knowing this. It just seems to me it is the registration systems job to know what classes people are signed up for and not a users job…but it is a gut reaction.

By: Brian Kotek

Brian Kotek — Thu, 10 Jan 2008 16:55:52 +0000

I have a fully dyanamic dependency injection observer for Transfer Objects that is in the hands of Mark and Chris Scott now. If they agree that it looks all right, it will either be included in the next version of ColdSpring or I’ll put it up on RIAForge. It autowires your decorators without you having to do anything.

Brian, regarding your comment about beans talking to services, what is your concern with this? I do it all the time. It just means the beans can be smart. In this example, I’d say it’s perfectly fine to ask a user about their registrations. “Hey Bob, what classes are you signed up for?” as opposed to “Hey Mr. Manager, what classes is that guy Bob signed up for?”

By: Brian Rinaldi

Brian Rinaldi — Thu, 10 Jan 2008 13:58:04 +0000

Interesting. Though I am not sure I agree with the architecture. To me you would pass the user to the AttendeeService and see what he is registered for. Seems like knowing his registrations is beyond the scope of what a user should know (plus I just don’t like the idea of making a bean dependent on a service).

By: Paul Marcotte

Paul Marcotte — Thu, 10 Jan 2008 06:52:03 +0000

Thanks for posting this Brian. I just finished a similar, but less robust, solution. I like yours a *lot* more.