{"id":"four-decoupling-patterns-topology","text":"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.","truth_value":"IN","source":"","source_url":"","source_hash":"","justifications":[{"type":"SL","antecedents":["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"],"outlist":[],"label":"Decoupling patterns span a topology from reified request to implicit broadcast"}],"dependents":["command-dual-role-decoupling-and-state","decoupling-topology-composition-based"],"metadata":{"source_type":"derived","review_result":"pass"},"created_at":"2026-06-17T17:53:17+00:00","updated_at":"2026-06-18T06:15:08+00:00","reviewed_at":"2026-06-18T06:15:08+00:00","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"four-decoupling-patterns-topology","truth_value":"IN","reason":"SL justification valid","antecedents":["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"],"label":"Decoupling patterns span a topology from reified request to implicit broadcast"},{"node":"four-patterns-decouple-senders-receivers","truth_value":"IN","reason":"premise"},{"node":"command-decouples-invoker-from-receiver","truth_value":"IN","reason":"premise"},{"node":"gof-mediator-replaces-many-to-many-with-one-to-many","truth_value":"IN","reason":"premise"},{"node":"chain-of-responsibility-implicit-receiver","truth_value":"IN","reason":"premise"},{"node":"gof-observer-intent-one-to-many-dependency","truth_value":"IN","reason":"premise"}]}}