Comments on: No Mediator vs. No Singleton in Cairngorm & PureMVC

By: Aaron

Aaron — Fri, 19 Sep 2008 04:03:10 +0000

Jesse,

Thanks for being brave enough to suggest that some specific frameworks, ideologies, or theories may not be all they’re cracked up to be in practice. It’s like a form of political correctness for techies where you look around worrying if someone might be offended even it wasn’t meant in such a way.

Anyway, I’ll toss out a post I wrote on a related topic for anyone who cares:
http://aaronhardy.com/flex/the-best-flex-mvc-framework/

By: Andrew

Andrew — Sun, 14 Sep 2008 22:48:51 +0000

Having just started a Flex project I decided that I needed a framework. My rationale was that I had good experiences with Spring and Struts and EJB3 on the server side, so the “frameworks are good” idea was in my head.

Did all the research. Picked pureMVC. Been coding for 3 months. Using it less and less. Starting to dislike it. I have evolved to the position that none of these frameworks actually provide anything to you. I think the MVCS or Model View Presenter patterns are the closest to being correct, but no framework has done any of this correctly. I think they all try and do too much.

By: Theo

Theo — Sat, 13 Sep 2008 20:18:02 +0000

Are we talking about the same thing? You mention Martin (Fowler, I assume), which makes me thing we do, but it doesn’t make sense to me. I don’t get why nested views create a problem, and what code behind has to do with this also escapes me.

By: JesterXL

JesterXL — Sat, 13 Sep 2008 18:47:04 +0000

Yes I know, and it works great with the .NET world in a code behind fashion. My issue, however, is that as you know, Flex apps consist of many nested View’s; it’s not always flat. Therefore, if you treat Presenter’s as instances that a View has a reference too, the only way to share code is to share those instances… which gets nasty. If you make it a Singleton, you effectively have the C in MVCS.

By: Theo

Theo — Sat, 13 Sep 2008 18:05:16 +0000

@Jesse

Either I misunderstand you, or you have misunderstood the Presentation Model pattern. As I read your comment, you seem to think that the presentation model is a single entity shared by all views in the application, but this is not the case.

There should not be only one presentation model in an application, but many. Each view class has it’s companion presentation model class, and each view instance has it’s own presentation model instance.

Really it’s just like mediators in PureMVC, but the responsibilities are different.