Simple State Machine with transitions, guards, composite state.

...but without sub-state machine, deferred signals, event queues...

Define the State Machine by subclassing State Machine and using the builders in the constructor. Se tests for usage.

    State onHold = state(ON_HOLD)
            .transition(HURL_PHONE).guardedBy(event -> PHONE_HURLED_AGAINST_WALL.equals(event.getName()))
            .to(phoneDestroyed)
            .transition(HANG_UP).guardedBy(event -> HUNG_UP.equals(event.getName()))
            .to(offHook)
            .transition(TAKE_OFF_HOLD).onTransition(stopMuzak).guardedBy(event -> TOOK_OFF_HOLD.equals(event.getName()))
            .to(connected)
            .build();

Inspired by simplestatemachine

Phone State Machine (Generated from code by Graphviz)

Inspired by ATM Bank

ATM State Machine (Generated from code by Graphviz)

The composite state ServingCustomer

A model containing the ATM state machine and the inner states of the composite state (not generated from code)