Messagewhether

Messagewhether is a term used in the context of message-oriented systems to describe a decision predicate attached to a message that determines whether the message should be processed, delivered, or routed further. The word is a portmanteau of message and whether, emphasizing the conditional nature of handling rules applied to messages. It is not part of a formal standard; rather, it appears in technical discussions and some documentation as a pattern for conditional message processing.

Definition: A messagewhether can be a boolean flag, a function, or a policy expression that evaluates to true if the message meets predefined criteria. Evaluation can consider metadata (sender, timestamp, priority), payload content (schema, keywords), or external context (user state, system load).

Usage: In publish-subscribe systems, a messagewhether predicate can filter publications before delivery. In workflow or orchestration engines, gates or routers may rely on messagewhether checks to decide which path a message takes. In access control, a messagewhether may enforce that only messages from authorized sources are processed.

Implementation notes: Keeping predicates deterministic and side-effect free helps reproducibility. Efficiency matters, especially in high-throughput systems, and predicates should be designed to avoid costly operations on every message.

Relation to related concepts: Similar ideas appear as filters, guards, predicate routing, and policy-based routing.

See also: filtering, routing, predicates, access control.