#dddDesign

Nick Tune

@nick-tune.me

4 months ago

Phase 1: Learn Domain A accesses Domain B's data in the legacy directly

Phase 2: Migrate The concept is validated, so migrate required logic to Domain B, create an interface, and migrate Domain A's dependency on the legacy to the new interface.

Legacy-leveraged learning phase is the name I use for a pattern we've been using at PayFit in a few places recently.

This pattern is controversial because it violates my most important modernization principle: respect domain boundaries.

1/4

#legacyModernization #dddDesign

Nick Tune

@nick-tune.me

11 months ago

Evolution of code model and mental model over time. At the start they are the same, but with each evolution they start to get more and more mis-aligned.

An under-appreciated benefit of architecture modernization is the chance for semantic convergence (of your software and mental model).

It's common in legacy systems for words and concepts not to align with how people think and talk about the business.

1/4

#architectureModernization #dddDesign