New Wisper feature, an alternative to global listeners: class scoped listeners.

01-interactor.rb

# without new Wisper feature:

# interactor
class CreateDelivery
  include Wisper::Publisher
  
  # alternative constructor which also adds some listeners
  def self.with_default_listeners
    new.tap(&:add_default_listeners)
  end
  
  def execure(attributes)
    delivery = # ...
    broadcast(:create_delivery_successful, delivery)
  end
  
  # problem is we are adding hard dependencies here...
  def add_default_listeners
    [StatsListener.new, NotifierListener.new].each { |listener| subscribe(listener) }
  end
end

# usage

interactor = CreateDelivery.with_default_listeners
interactor.execute(params[:form])

02-alternative.rb

# With new Wisper feature:

# adds listeners to all instances of given class, instead of globally.
CreateDelivery.add_listener(StatsListener.new) 
CreateDelivery.add_listener(NotifierListener.new)

# This would have the same effect as the first code, except:

# * listeners are no longer hardcoded in the class
# * there is no need for a special constructor

# interactor
class CreateDelivery
  include Wisper::Publisher
  
  def execure(attributes)
    delivery = # ...
    broadcast(:create_delivery_successful, delivery)
  end
end

# usage

interactor = CreateDelivery.new
interactor.execute(params[:form])

krisleech/wisper#31