I have written favorably about both Cairngorm and PureMVC, and this has led a number of people to ask which framework I prefer. Rather than make a blanket statement that one framework is better than the other, it seems more profitable to take a few moments to discuss some of the strengths and weaknesses of each.

Let’s start by emphasizing that the two frameworks share a number of strengths. Both of them provide conventions that, once learned, enable you to build complex applications faster. Both of them lend themselves (in varying degrees) to team development. Both of them promote some level of code reuse. Both of them help you make applications that are easy to maintain and extend. Both of them will enable you to build applications that any experienced Object-Oriented developer will be able to get up to speed on very quickly. Both of them give you complete control over event flows. (When using native Flex events, you need to be aware of bubbling, and whether there is any native Flex code that is also listening for the event you’re dispatching, but each of these frameworks addresses this issue - PureMVC implements a publish/subscribe system with its notifications, and Cairngorm uses CairngormEvent/CairngormEventDispatcher.)

Having looked at what the two frameworks have in common, let’s now take a look at what makes them different. Since we’re talking about Flex frameworks, I thought it would be fun to put the comparison matrix in an AdvancedDataGrid component:

You can open and interact with the matrix here. (Building it wasn’t as much fun as it should have been, but I’ll address that in a future post.)

I’m sure there’s much more that could be said, and I hope that you’ll add your thoughts to this discussion. If you don’t want to post your comments/questions here in the blog, feel free to contact me directly.

Cliff Hall has released a new version of PureMVC with various improvements which you can read about here. In conjunction with this release, Cliff has also unveiled the Manifold Project, which provides numerous demos and ports of PureMVC to languages other than ActionScript 3. I am proud to say that I am participating in the open-source Manifold Project, and my Flex-on-Rails application, “Index Cards,” is now a Manifold demo application. From this point forward, you can keep abreast of the development of Index Cards, report bugs, and suggest new features via its Manifold project site.

Kudos to Cliff, who had to do a tremendous amount of work to pull this off. I suspect that a lot of developers will benefit from the effort.

I’ve completed the first iteration of a Flex-on-Rails application, and had a lot of fun doing so. The application is called Index Cards, and it’s designed to be a generic study aid. The metaphor is simple: on one side of the index card, you write the name of a concept that you wish to learn, and on the back you write a definition and/or description of that concept. Of course, you’ll have a separate set of index cards for each subject that you study, and within each subject you will further divide your index cards based on topics or categories. You put all of the cards for each topic or category in a rubber band to keep your cards from becoming disorganized. For example, if the subject you’re studying is elementary statistics, you might have one rubber band to hold cards with descriptive analysis concepts, another rubber band for probability, and so on.

Unfortunately, I haven’t lined up Rails hosting as yet, so I don’t have an online demo to play with. However, you can download the source code here. Please let me know if you have any feedback (criticisms, suggestions, kudos, etc.). Most of the code is still uncommented, so feel free to ping me with any questions as well.

In addition to being my first significant Rails application, this is also my first use of the PureMVC framework. I will admit that this slowed me down much more than expected, as I had some trouble wrapping my mind around PureMVC. However, now that I’m starting to get the hang of it, I think I like it. I will have a better idea of how much I like it when I start adding functionality. I’ll be posting comments here as I build out the app, so stay tuned.

As it stands, the application has the basic required functionality: you can create, update, and delete index cards, and you can flip through the cards to study them. However, I plan to add (at bare minimum) the ability to study only one rubber band at a time. I also hope to add user management and login functionality so that there could be multiple users of the same instance, as well as different ways of studying with the index cards (multiple choice etc.).

Below is a list of resources that were instrumental in getting me to this point.

Rails:
Agile Web Development with Rails (of course) by Dave Thomas, David Heinemeier Hansson, et al
Rolling with Ruby on Rails Revisited by Bill Walton and Curt Hibbs
Integrating Flex 2 and Ruby on Rails by Derek Wischusen

PureMVC:
PureMVC Best Practices by Cliff Hall
Cafe Townsend demo by Michael Ramirez (This is an adaptation of the Cairngorm demo for PureMVC)