And now for something completely different

This is my first week of a 3 weeks vacation. It is really hot in Munich why I am currently enjoying swimming, biking and visiting beer gardens more than software engineering.

Nonetheless, I am currently educating myself in a new programming language. Scala by Martin Odersky combines a pure object-oriented langauge with functional features. And it runs on the JVM. An earlier version of Scala does also support the .NET CLR.

What I like most is the proper integration of functional features. Closures, for comprehensions, nested functions, pattern matching are notable examples. While Scala is statically typed (it is not a dynamic language), it offers type inference for variables, arguments and results.

In addition, it provides some cool extensions to Java: all types are objects, no static members, support of covariance and contravariance, to name a few.  Traits are available instead of interfaces – they can behave like interfaces but also allow implementations of methods. With traits the problem of multiple inheritance (mind the diamond configuration) can be avoided. This is possible by introducing inheritance linearization and a kind of virtual super.

With all of these features Scala code can be much more compact than Java - and it interoperates well with Java components.

Well, I am really kinda enthusiastic. If you ask me, Scala could be a strong competitor for Java and C#.  But of course, there is not a big company backing Scala such as Sun or Microsoft. Thus, the community will decide.

Loving the JVM but preferring other languages than Java? No more excuses, Dave!

Neverending Story

One of the prominent questions I often hear in software development projects is when to start with architecture design. Sometimes, architects hesitate to start until almost all requirements are available in high quality. This strategy is highly recommendable when you like to postpone architecture design forever. There is not a single project with medium to high complexity I remember where we knew all forces in full depth and breadth at project start.

First of all, it heavily depends on the software development process. In a Waterfall model without iterations you are stuck anyway. Thus, I generally recommend an iterative-incremental approach. In software developments with all their volatility only piecemeal growth can succeed.

It is important to have a sufficient quality and quantity of requirements available, for example, the most important 30%-50% of use cases and non functional qualities with unique priorities. This way, you can come up with a conceptual architecture which you can then use as a base for iterative-incremental refeinement.

After the baseline is available prioritize all user requirements (use cases), map them to end-to-end scenarios and integrate them into the architecture, keeping the non-functional qualities in mind. To deal with non functional qualities let key developers, architects or even teams work on principles and guidelines how to address these qualities. Do this after the baseline architecture design but before starting the end-to-end iterations.

As soon as new requirements appear or have been concretized assign them priorities and put them into the “backlog”.

To introduce a kind of safety net for embracing change, introduce test-driven design methods, flash architecture reviews after each iteration, and (architecture and code) refactoring activities after each flash review.

Keep in mind that sometimes you need courage to decide even when not all details are available.  It is typical for all creative and volative acts that not all details are known in advance, nor the ways how to cope with them.

As a consequence, it is much more productive and effective to follow wrong paths sometimes instead of following no path at all.

To keep it simple: Prefer acting over reacting