abstract class Athena::Contracts::EventDispatcher::Event
inherits Reference

An event consists of a subclass of this type, usually with extra context specific information. The metaclass of the event type is used as a unique identifier, which generally should end in a verb that indicates what action has been taken.

# Define a custom event
class ExceptionRaisedEvent < ACTR::EventDispatcher::Event
  getter exception : Exception

  def initialize(@exception : Exception); end
end

# Dispatch a custom event
exception = ArgumentError.new "Value cannot be negative"
dispatcher.dispatch ExceptionRaisedEvent.new exception

Abstract event classes may also be used to share common data/methods between a group of related events. However they cannot be used as a catchall to listen on all events that extend it.

Stopping Propagation

In some cases it may make sense for a listener to prevent any other listeners from being called for a specific event. In order to do this, the listener needs a way to tell the dispatcher that it should stop propagation, i.e. do not notify any more listeners. The base event type includes ACTR::EventDispatcher::StoppableEvent that enables this behavior. Checkout the related module for more information.

Included modules

Athena::Contracts::EventDispatcher::StoppableEvent