This pattern is part of "Patterns of Legacy Displacement"

Transitional Architecture

Breaking up the problem and delivery of the parts means a system's state evolves. The states, and temporary elements built to support them, won't endure once the legacy is fully displaced.

This page is a stub. We intend to fully expand it in later revisions of this material. However we are still in the middle of developing these patterns, so it's likely that patterns will be renamed, split, or merged as we continue to learn how best to frame and explain these ideas.

Our approach at a high level is:
  1. Define outcomes
  2. Break up the problem
  3. Deliver the parts
  4. Change the organisation

It advocates for incremental delivery, allowing benefits to be delivered early and the risks associated with Big Bang releases to be avoided. The approach means that the configuration of the architecture of the system will evolve over time as new parts are brought into service.

In order to enable these intermediate configurations - or Transitional Architectures - work will have to be done on integrations (using patterns like Event Interception or Legacy Mimic) that have no place in the target end state architecture.

Or to put this more directly - you will have to invest in work that will be thrown away.