2 years ago

A common feature of legacy systems is the https://martinfowler.com/articles/patterns-legacy-displacement/critical-aggregator.html, as the name implies this produces information vital to the running of a business and thus cannot be disrupted. Divert the Flow is a strategy that starts a Legacy Displacement initiative by creating a new implementation of the https://martinfowler.com/articles/patterns-legacy-displacement/critical-aggregator.html that, as far as possible, is decoupled from the upstream systems that are the sources of the data it needs to operate. Once this new implementation is in place we can disable the legacy implementation and hence have far more freedom to change or relocate the various upstream data sources.

Initially this implementation might receive data from existing legacy systems, for example by using the https://martinfowler.com/articles/patterns-legacy-displacement/event-interception.html pattern.

The Aggregator will change the data sources it uses as existing upstream systems and components are themselves displaced from legacy, thus it's dependency on legacy is reduced over time.