My posts on team development will start from a beginners understanding of programming, working up to an advanced look at architecture and design.

First thing’s first: What’s this MVC thing?

MVC stands for Model-view-controller. MVC aims to separate, or decouple, data (model) from the user interface (view) and functional logic (controller). You can read a lot more about MVC on the Wikipedia.

How do we use MVC in an RIA (specifically a Flex app)?

Well thought out architecture and design is important at every level of the application, but an RIA is different than a web app of the past in one important way: state. In legacy (HTML script-based) web apps state is, for the most part, required to live on the server. In RIA development we are not bound by this requirement. We can build RIAs that have state at the client or the server or a hybrid of both. This one fact completely changes the complexity and importance of what once was merely the view. In RIA development the part of our application that lives at the client level is not just an HTML rendering of a view, it can be a fully functional stand alone application. The client in a RIA has many of the characteristics of a desktop application and that is why MVC applies at this level.

Why is this called a micro-architecture?

We refer to architecture and design patterns at the Flex level as a mirco-architecture frameworks because the Flex application is a piece in the larger picture of the entire application. The Flex app may talk to one or more web services, consume an RSS feed, stream video, show images from the web, and so on. All of these services fit into the larger architecture of the web app. These architectural decisions are also important but a little harder to talk about generically. So, since this is a Flex blog, when I speak of architecture I’ll really be talking about client micro-architecture.

Why do you want to use a micro-architecture?

Actually, sometimes you don’t. If you’re creating a very simple app (something like a widget or a banner ad) MVC might not be for you. However, if you’re creating something that models data retrieved from a service, allowing the user to manipulate that data, and displaying the data in interesting ways… MVC is really a good choice to make.

What you get

1. A code base that facilitates team development.
2. A skill that will make your team more agile in their development life cycles.
3. Source that has a high level of maintainability and interoperability.

Ok.. let me unpack those a bit.

1. Your code base will facilitate team development most simply because the team is now coding to a convention. MVC isn’t really the big deal here, it’s the fact that a convention was decided on. MVC does offer some nice things in regards to team development that I’ll talk about in other posts, but my point here is that convention keeps everyone on the same page.

2. Every learn how to play an instrument or a sport? Each of these skills involves mastering patterns. The more your team implements on the patterns in MVC, the better skilled they will be at it. My point here is really that MVC should also be viewed as a problem solving tool. When you get developers thinking about solving architectural problems in the same way, everyone can solve that problem faster.

3. Maintainability and interoperability… again this really goes back to convention. Your code will be more maintainable by your dev team if it’s built on convention. If you chose a convention that’s fairly mainstream, then you gain a level of developer interoperability. Meaning, training in a new team members on the way you implement requirements will be a lot easier if your using a convention and on top of that a standard convention. In Flex development, Cairngorm is a nice way to go. It’s not necessarily the best framework out there, but it seems to be the most widely adopted Flex micro-architecture.

I’ll be delving deeper into MVC and Cairngorm in my next posts.

In the past year or so I’ve been playing the role of technical lead / architect on most of the Flex projects I’ve been working on. Usually this involves a team of 3-6 developers and 1-3 designers. The focus of my blog over the next few months will be to pass on the tips and tricks that I’ve learned as a lead developer working with other developers and designers, the bosses as well; PMs, technical managers, QA managers, customers… et al.

To get started a few tips:

Use source control

At EffectiveUI we typically use SVN repositories, but choosing the right technology isn’t really as important as making the choice to use source control. Also, make sure your source control servers are redundant, or someday you might wish you had.

Create an easy designer developer workflow

In the world of RIAs the ability to stay agile within a life cycle of a project hinges on this point. If getting from design to an implementation of that design is anything less than nimble, you’ll feel some pain.

Patterns, paradigms, and frameworks… oh my

Select and use a micro-architecture that makes sense for your dev group and/or application. Cairngorm is one of the more popular micro-architectures used in Flex development, it’s what we use at EUI.

The benefit and problem with most Flex micro-architectures is: keeping the framework light weight and simple also means that (while providing flexibility) they do not provide enforceability. In some areas this is, arguably, a good thing and in others it’s not so good.

Needless to say, most of my posts will focus on Cairngorm and how we have used and tweaked it to create a good software design as well as an agile development environment.

Stay tuned for more….
-adam