A few weeks ago there was a kick-off for the ‘workshop season’ at Logica. The IDT Java department made a very broad roadmap of workshop topics of which Domain Driven Design (DDD) was the first to be held. On May 5th and 7th the DDD workshop was held in Rotterdam. The workshop was centered around the philosophy of DDD and some practice with the material.

The first day we had some discussions about what DDD is and how it relates to normal Object Oriented Design. This led to some very interesting discussions, that helped a lot at creating a shared view on what a model is and what design is and what DDD is. Although I can imagine that a bit of background in OOD was a prerequisite in order to participate in these discussions.

To make a long story short; the center of domain driven design for us was: a design strategy where the design of the application is centered around the (problem) domain of the customer, written down in a model with an Ubiquitous Language and that this domain model should be used as a language among all/most stakeholders. Also noted as important, was the emphasis on the refactoring of the model, the agile iterative approach for creating this artifact. With this definition the difference with OOD is that DDD is broader, it favors the agile development approach and at the same time it is more strict (it gives more guidance in how your class model should be created). So some of us realized that parts of the DDD philosophy were already part of their current process.

The second session was a ‘modeling out loud session’ where we created a model for a business case using the theory of the first session. This also led to better understanding of the patterns of DDD with entities, value objects, services, repositories and factories. During this session our definitions of these patterns were refined, and also the gap between these abstract terms and for instance the Spring Framework was crossed. This held back the progress of creating the model for the business case, but of course led to a deeper understanding of the material. Eventually, with the help of the experienced DDD trainers, we made a nice domain driven design for the business case. And all participants received a copy of Eric Evans’ DDD bible so they can further expand their knowledge on this subject

More info on domain driven design can be found here.

( Logica employees interested in these kind of sessions should contact the manager of the Java IDT competence, but be aware that most sessions are very popular and the number of available places are limited. Other workshops that are coming up: Spring essentials, jQuery and Java Performance Tuning ).

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