Coding the Architecture - asp tag

.NET systems need software architecture too

Mon, 24 Nov 2008 21:20:43 GMT

Although most of my experience has been building Java systems, I have worked alongside a few .NET development teams over the past few years, particularly in the banks where many of the new systems being built make use of a range of technologies. One thing that I've always found odd is that, if pushed, many Java developers will claim that they've undertaken some software architecture whereas most .NET developers won't. And these aren't junior developers either. I've met some people who really know their .NET but seem reluctant to use the "architecture" word.

I'd be really interested to hear other people's views on this because I'm not exactly sure why this is. Perhaps some of it can be put down to the Microsoft stack being integrated in a way in which it's clear how certain types of applications should be built; whether it's a database-driven website or a desktop application accessing data from a collection of web services. Perhaps it's just that the people I spoke to were only building small applications that didn't need a rigourous architecture. Maybe the "Microsoft way" (as promoted on MSDN, etc) is just the de-facto approach. Who knows.

Now that I've been working in-depth on a complete .NET system (ASP.NET website, WCF services, SQL Server, etc), I don't really perceive any difference between this and the sort of Java systems that I've built in the past. There are multiple distributed tiers, the business logic is being written in a rich OO programming language, there's XML, there are databases, there are external systems and so on. Throw into the mix some complex non-functional requirements around security and no longer is this a simple "My first ASP.NET application". To further complicate matters, like Java EE, there are now a number of different technologies that can be used to achieve the same end-goal. ASP.NET or ASP.NET MVC? WCF, WSE or .NET remoting? Is this all running on a single IIS instance or are we splitting it across multiple boxes?

For a .NET project like the one that I'm working on, software architecture is just as essential as any other Java system that I've worked on in the past. Everybody needs to be more architecturally aware, but my experience suggests that .NET development teams seem reluctant to use the "architecture" word. Why is this?

Becoming more architecturally aware - part 2

Tue, 28 Oct 2008 20:18:49 GMT

Last time I talked about how we need to understand how application frameworks are designed and work behind the scenes in order to produce code that is consistent and compliant with the overall architectural principles. The second aspect that we need to become architecturally aware about is the underlying technology.

Again, let's put this in context of my current .NET project. I have much more Java experience than .NET experience; I've written some C# and I've played with Silverlight, but ASP.NET is new to me. Thankfully, the concepts behind ASP.NET translate fairly directly with those behind JSP, so it's not as if I'm tackling this from a standing start. Having said that, I've felt that it's really important to get to grips with the underlying architecture of the technology so I can be sure that the code I write, again, integrates properly into the overall architecture. An example here would be the ASP.NET page life cycle. Like JSP, ASP.NET pages have a series of things that happen to them when a request is made, which includes creation of the request/response objects, page compilation, page instantiation, calling page event handlers and so on.

Knowing the finer details of a programming language is one thing, although using or not using new language features such as generics isn't necessarily going to negatively affect the architectural integrity of the solution. Not understanding something like the page life cycle of ASP.NET could. For example, it's important to understand the page life cycle so that you understand when objects can be shared/cached. Session management is another important thing to understand, and blindly throwing objects into the user's session can have architectural implications if your application needs to scale horizontally and you need to implement transparent session failover using session replication.

Being more architecturally aware doesn't necessarily mean that you need to understand the entirety of the bigger picture, but you should understand how to write code that is architecturally compliant. And that means understanding more about how the underlying technologies work.

Becoming more architecturally aware - part 1

Fri, 17 Oct 2008 09:06:00 GMT

In my Mind the gap essay and Why Software Projects Fail presentation, I talk about how we as developers should be more architecturally aware if we are to bridge the gap between the code and the overall design. I include myself in this statement because recently I've started adding functionality to an existing ASP.NET website and I've found it essential that I become as architecturally aware as possible in a short amount of time. Let me provide a couple of real world examples.

Although I'm adding behaviour that is in effect isolated from the rest of the application, my code is still a constituent part of the overall architecture. In addition, I'm using some of the utilities and frameworks that the development team have already produced. Clearly I need to understand the usage patterns in order that I can be productive as a developer on the team but, furthermore, I need to understand something about the inner workings in order that the code I write is architecturally compliant with the rest of the system. I'm sure you've seen this yourself, but give a few people the same framework and you'll see usage patterns that you hadn't even dreamed of. Some will be what you expected, some may be better than what you expected and some may break your framework in horrible ways.

If somebody on the team is taking responsibility for the architecture and undertaking reviews, it's possible to catch those instances where application framework code isn't being used as anticipated. Sometimes, it's even possible to automate these architectural conflicts with a set of automated unit tests. If, however, nobody is taking on this architectural guardian role and everybody is simply using what they've been provided with, then this is where problems start to creep in. Sometimes they creep in from people adopting a copy-paste approach to development (i.e. copying another class because it "works") and sometimes they creep in because people just aren't aware of the hidden side effects of their framework usage pattern. Either way, problems introduced because of a lack of architectural awareness might not show up during local single-user testing, but could prove critical when the system is rolled out to a wider user base.

The only way to get really productive with existing application code is to dive into it and understand how it works at both a conceptual and implementation level. Only then can you ensure that the code being written is compliant with the rest of the architecture, which is crucial for the quality and integrity of the solution. This is one way in which developers should become more architecturally aware and next time I'll discuss another.