Domain-Driven Transformation

Chapter 15. Summarizing Domain-Driven Transformation

Coming to the end of the book, this chapter distills the method we presented.

Even if legacy systems are in poor condition or lying on the ground as a wreck, there is still a treasure of domain knowledge slumbering in them. In most cases, this domain treasure is valuable enough to bring it out of hiding into the light again, instead of replacing it with a redevelopment. This is because with a redevelopment, we are dealing with so many unknown unknowns that the actual effort exceeds the estimates many times over.

Like redevelopment, improving a legacy system is very time-consuming. With Domain-Driven Transformation, this undertaking can be carried out in small steps and thus with less risk. We have shown you how to do that in this book. In order to unearth the treasure of domain knowledge in a legacy system, we have to identify the parts of the source code that contain the valuable business knowledge of our domain. We want to strengthen these parts with domain knowledge, thus freeing them from the solution dust of years of decline, and transfer them, brightly polished, into the new world. Very poetic, isn’t it?

We have divided our approach for the transformation of legacy systems into two parts with corresponding subtasks (see Figure 15-1), and in “The Method”, we gave you the tools to decide how to proceed in detail:

Technical, tactical, and team-organizational Domain-Driven Transformation

If your legacy system is a big ball ...