Status: IN
The four sender-receiver decoupling patterns form a topology spectrum: Command reifies requests as objects, Observer broadcasts via subscription, Mediator centralizes through a hub, and Chain of Responsibility forwards along an implicit chain — each making a different structural tradeoff between coupling shape and flexibility.
Decoupling patterns span a topology from reified request to implicit broadcast
Depends on (SL): four-patterns-decouple-senders-receivers, command-decouples-invoker-from-receiver, gof-mediator-replaces-many-to-many-with-one-to-many, chain-of-responsibility-implicit-receiver, gof-observer-intent-one-to-many-dependency