KState/ca.acendas.kstate.events/StateMachineBuilder

StateMachineBuilder

class StateMachineBuilder<S, E : StateEvent>

DSL builder for creating state machines with a fluent API.

This builder provides a declarative way to define state machines similar to the coroutine-based guide but adapted for zero dependencies. It supports event handling, state transitions, guards, and side effects.

Parameters

The type of states in the state machine

The type of events in the state machine

Constructors

StateMachineBuilder

constructor()

Properties

initialState

var initialState: S?

The initial state of the state machine. Must be set before building.

starting

val <S, E : StateEvent> StateMachineBuilder<S, E>.starting: InitialStateStarter<S, E>

Starts the initial state configuration with "starting at State" syntax.

validator

var validator: StateValidator<S>

Optional validator for state validation.

watching

val <S, E : StateEvent> StateMachineBuilder<S, E>.watching: ChangeWatcher<S, E>

Starts observer configuration with "watching" keyword.

Functions

during

inline fun <S : Any, E : StateEvent> StateMachineBuilder<S, E>.during(state: S, configuration: StateConversationalScope<S, E>.() -> Unit)

Configures a state with conversational syntax: "during State { ... }"

initially

infix fun <S, E : StateEvent> StateMachineBuilder<S, E>.initially(state: S)

Alternative syntax for setting initial state: "initially State"

observe

fun observe(observer: StateObserver<S>)

Adds an observer to the state machine.

fun observe(observer: (oldState: S, newState: S) -> Unit)

Adds an observer using a lambda.

onAny

inline fun <T : E> onAny(handler: StateEventHandler<S, T>)

Adds a global event handler using reified generics.

fun <T : E> onAny(eventClass: KClass<T>, handler: StateEventHandler<S, T>)

Adds a global event handler that applies to all states.

onEveryTransition

fun <S, E : StateEvent> StateMachineBuilder<S, E>.onEveryTransition(effect: (oldState: S, newState: S) -> Unit)

Adds a global side effect that runs on every transition.

sideEffect

fun sideEffect(effect: (oldState: S, newState: S) -> Unit)

Adds a side effect that runs on every state transition.

state

inline fun <T : Any> state(noinline configuration: StateConfiguration<S, E>.() -> Unit)

Configures a specific state using reified generics.

fun <T : Any> state(stateClass: KClass<T>, configuration: StateConfiguration<S, E>.() -> Unit)

Configures a specific state in the state machine.

tracking

infix fun <S, E : StateEvent> StateMachineBuilder<S, E>.tracking(with: String): ((S, S) -> Unit) -> Unit

Adds an observer using "tracking with" syntax.

validateWith

infix fun <S, E : StateEvent> StateMachineBuilder<S, E>.validateWith(validator: StateValidator<S>)

Sets the state validator directly.

validating

infix fun <S, E : StateEvent> StateMachineBuilder<S, E>.validating(with: String): (StateValidator<S>) -> Unit

Sets the state validator with conversational syntax.