@startuml

allowmixing

abstract class StateMachineManager<E extends StateMachineEvent, S extends StateMachineState> {
  + states: async* S
  - machines: [StateMachine<E, S>]
  - queue: Queue<E>
  --
  + accept(E event): void => queue.add(event);
  - dispatch(E event): void => machines[E].accept(event);
  --
  + {method} << public API methods >>
}

abstract class StateMachine<E extends StateMachineEvent, S extends StateMachineState> {
  + states: async* S
  - manager: StateMachineManager<E, S>
  - queue: Queue<E>
  + accept(E event): void => queue.add(event);
  - dispatch(E event): void => manager.dispatch(event);
  - emit(S state): void => states.add(state);
}

abstract class StateMachineEvent {
  + type: String
}
abstract class StateMachineState {
  + type: String
}

StateMachineManager *- StateMachineEvent
StateMachineManager *- StateMachineState
StateMachine *- StateMachineEvent
StateMachine *- StateMachineState
StateMachineManager o- StateMachine

actor Developer
Developer -> StateMachineManager

@enduml