MessageHandlerBuilder<M, D, C> class

Provides methods for describing how a state, carrying state data of type D, behaves in response to a message of type M.

In some specialized situations, the builder may also carry a contextual value type C. In the general case C will be void.

A MessageHandlerBuilder is provided to the build callback provided to StateBuilder.onMessage, and is used to describe how messages of a particular type are handled by a state.

class MyMessage {}
var state1 = StateKey('s1');
var state2 = StateKey('s2');
var builder = StateTreeBuilder(initialState: state1);
builder.state(state1, (b) {
  // Describe how state responds to MyMessage messages
  b.onMessage<MyMessage>((b) => b.goTo(state2));
});

Constructors

MessageHandlerBuilder(StateKey forState, FutureOr<C> makeContext(MessageContext), Logger log, String? messageName)

Properties

act → MessageActionBuilder<M, D, C>
A MessageActionBuilder that can be used to specify actions that should take place when handling messages.
latefinalinherited
descriptor ↔ MessageHandlerDescriptor<C>?
getter/setter pairinherited
hashCode → int
The hash code for this object.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

action(MessageActionDescriptor<M, D, C> action, [ActionResult actionResult = ActionResult.handled]) → void
Indicates that an action should take place when handling a message, and that no state transition should occur.
enterChannel<P>(Channel<P> channel, FutureOr<P> payload(MessageHandlerContext<M, D, C>), {MessageActionDescriptor<M, D, C>? action, bool reenterTarget = false}) → void
Indicates that channel should be entered and a transition to the channels state should occur.
inherited
goTo(StateKey targetState, {TransitionHandler? transitionAction, FutureOr<Object?> payload(MessageHandlerContext<M, D, C> ctx)?, MessageActionDescriptor<M, D, C>? action, bool reenterTarget = false, String? label}) → void
Indicates that a transition to targetState should occur.
inherited
goToSelf({TransitionHandler? transitionAction, MessageActionDescriptor<M, D, C>? action, String? label}) → void
Indicates that the message has been handled, and that a self transition should occur.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
stay({MessageActionDescriptor<M, D, C>? action}) → void
Indicates that the message has been handled, and no state transition should occur.
toString() → String
A string representation of this object.
inherited
unhandled({MessageActionDescriptor<M, D, C>? action}) → void
Indicates that the message has not been handled, and the message should be dispatched to ancestor states for processing.
when(FutureOr<bool> condition(MessageHandlerContext<M, D, C>), void buildTrue(MessageHandlerBuilder<M, D, C> builder), {String? label}) → MessageHandlerWhenBuilder<M, D, C>
Describes message handling behavior that may be run conditionally, sharing a context value among conditions.
whenResult<T>(FutureOr<Result<T>> result(MessageHandlerContext<M, D, C>), void buildSuccess(MessageHandlerBuilder<M, D, T> builder), {String? label}) → MessageHandlerWhenResultBuilder<M, D, C, T>
Describes message handling behavior that runs conditionally, depending on a Result value.
whenWith<C2>(FutureOr<C2> context(MessageHandlerContext<M, D, C> ctx), FutureOr<bool> condition(MessageHandlerContext<M, D, C2> ctx), void buildTrue(MessageHandlerBuilder<M, D, C2> builder), {String? label}) → MessageHandlerWhenBuilder<M, D, C2>
Describes message handling behavior that may be run conditionally, sharing a context value among conditions.

Operators

operator ==(Object other) → bool
The equality operator.
inherited