How was reactive recalculation triggered during status transitions and related side effects?

Reactive recalculation during status transitions is usually triggered by subscribing to a stream of status change events, for example, using Flux or Mono in Project Reactor. Each status change triggers an operator that initiates recalculation and side effects.

It roughly looks like this:

• The status change event enters the stream.
• An operator like flatMap or map is used to trigger recalculation, which can be asynchronous.
• In the chain, doOnNext or doOnSuccess can be added to perform side effects, such as sending notifications or updating caches.

This approach allows declarative description of reaction logic to changes, making it easy to scale and test.

Example:

statusChangesFlux
    .flatMap(newStatus -> recalculateMetrics(newStatus))
    .doOnNext(metrics -> sendNotifications(metrics))
    .subscribe();

Where statusChangesFlux is the stream of status changes, recalculateMetrics is a method returning a Mono with the recalculation result, and sendNotifications is a method with a side effect.