tl;dr Patterns, 20 Years Later: Observer ...
Some questions arise out of this:
A Observer tends to lead to several consequences:
A couple of different takes on the Observer include:
When messages are being sent to a single message queue or topic with multiple registered handler/processors, we refer to that as an Event Bus. If the first interested handler/processor on the bus pulls the message off the bus, it is a Chain of Responsibility; if the messages continue down the bus so that all interested handler/processors get a chance to see it, it is more of an Observer.
Last updated: 25 February 2022
Tags: pattern behavioral architectural