publisher.rb

module Publisher

  def self.included(base)
    base.instance_eval do
      @class_registrations ||= Set.new
      include Wisper.model
      # ensures we override Wisper's definitions
      include InstanceMethods
      extend ClassMethods
    end
  end

  module InstanceMethods
    private
    def registrations
      local_registrations + class_registrations + global_registrations + temporary_registrations
    end

    def class_registrations
      self.class.registrations
    end
  end

  module ClassMethods
    def subscribe(listener, options = {})
      @class_registrations << ::Wisper::ObjectRegistration.new(listener, options.merge(:scope => self))
    end

    def registrations
      @class_registrations + (superclass.try(:registrations) || [])
    end
  end

end

module Wisper
  class ObjectRegistration

    # For the registration to broadcast a specified event we require:
    #   - 'should_broadcast?'    - If the listener susbcribed with an ':on' option, ensure that the event
    #                              is included in the 'on' list.
    #   - 'listener.respond_to?' - The listener contains a handler for the event
    #   - 'publisher_in_scope?'  - If the listener subscribed with a ':scope' option, ensure that the
    #                              publisher's class is included in the 'scope' list.
    def broadcast(event, publisher, *args)
      method_to_call = map_event_to_method(event)
      if should_broadcast?(event) && listener.respond_to?(method_to_call) && publisher_in_scope?(publisher)
        broadcaster.broadcast(listener, publisher, method_to_call, args)
      end
    end

    private

    def publisher_in_scope?(publisher)
      allowed_classes.empty? || (allowed_classes.include? publisher.class.name)
    end
  end
end