High productivity in software development

It is relatively easy to show that abstract domain model driven agile application development is at the absolute complexity minim within all know application development methods for von Neumann computers.

This means of cause that this is most productive way to do it.

This method starts with creating an abstract domain model for the organization from scratch. This activity can takes up to 15 working days from analyzing group but in average is less than 10 working days. The result is something that I call object-oriented abstract domain model. It consists of one class model (named classes, a few essential attribute, core business methods and all class relations: associations and inheritance trees).

This abstract model states the essential business process requirements in a very rigid object-oriented languages. This is actually the most compact and coherent presentation for these requirement.

The next step is to design the necessary work flows into GU-conversation that are based and supports the earlier created domain model.

The implementation follow the three-tier architecture, where the domain layer is completely separated from the rest of the code. The implementation start from selection the hardware and software platforms for this implementation. The next step is to generate the domain layer skeleton from the domain model. After this the implementation proceeds incrementally adding both application and domain behavior simultaneously. This all happens in close direction of product owner and the becoming user community.

The ratio of the code sizes between three layer are typically following. The domain layer including all business logic is between 10 – 20 % of the code. The size of persistence layer varies the most depending on selected db solution. This depend heavily on the environment. If one has several old databases behind the new solution, this will require substantially code between domain objects and databases. If one can use one new relational db, then one can use JPA framework and reduce this work. My favorite is object database, which end up with least work. So this layer can be from a few percentage up to max perhaps 40 %. The application will then fill up the 100%.

The model generation will create in average 50 – 90 % of the final domain layer code. So if your ready application consists of 100 000 lines of Java then the business layer take 20 000 lines and all business logic methods about 4000 lines.

I have published here business line abstract domain model. Still I insist on doing it “ from scratch”. The model I have provided here should be used to guideline the modeling and they can be used for jump start for a novice modeling group to avoid very drastic mistakes. The model is after all the hart of the system and its design. Its influence to the whole system is many time more important than its ratio in code lines.

In may next post I will tell my experiences on how to learn to analyze reality and create these models. When I start doing this 20 years ago I thought that this is very easy for all of us but I proved bitterly to be wrong in this!

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