Objectively, what are the pros and cons of Cairngorm over PureMVC?

Question

There are so many reasons why using an MVC framework in Flex rocks, but picking the right one seems tricky. I am interested in what you all think from your experiences of implementing either of these (or another).

Sam

Answer 1

The question has already been asked, however since you ask specifically for the benefits of Cairngorm and PureMVC specifically, these are my thoughts:

• Both PureMVC and Cairngorm make it hard to write testable code. This is mostly down to their use of global variables that tie your application code together tightly, making it hard to isolate any part for testing. This is more true of Cairngorm than PureMVC, but both are pretty bad.

• PureMVC is more invasive than Cairngorm (meaning that your code is heavily dependent on the framework, e.g. you have to subclass/implement the framework classes/interfaces), but that doesn't mean that Cairngorm isn't.

• Cairngorm is full of anti-patterns like heavy use of global variables, PureMVC hides the worst parts of itself.

• PureMVC is anti-Flex, Cairngorm just doesn't use many of the good parts of Flex. By this I mean that PureMVC reinvents many things that Flex already have, because it wants to be platform agnostic, and because of its architecture, specifically the mediators, it makes it harder to use bindings to their full power. Cairngorm just skips over things like event bubbling, and instead opts for solutions involving global variable.

In short, Cairngorm is the VisualBasic of Flex, it works but will teach you a lot of bad habits. PureMVC isn't so bad, it just isn't a very good fit for writing Flex applications.

What I think you should look at is Mate, which uses Flex to it's full potential, and it isn't built around global variables. Instead it helps you write loosely coupled, testable, reusable and maintainable code without the heavy and needless dependencies on the framework that you see in other application frameworks.

If you for some reason don't like Mate, try Swiz, which is a great improvement over Cairngorm, but still has some weird preference for using global variables for central event dispatching (which is completely bizarre considering that one of the points of the framework is to avoid the evil global variables of Cairngorm).