NOTE
State Diagrams
Modeling finite states, transitions, events, guards, and lifecycle invariants.
This is a historical learning note and may contain outdated or incomplete understanding.
A state diagram models an object’s valid states and the events/conditions that move it between them. It is particularly useful for orders, payments, jobs, connections, workflows, and protocol lifecycles.
Define state invariants and legal transitions explicitly. Invalid or duplicate events should have known behavior. Persisting an enum is not enough if the transition rules are scattered across the codebase.