def callback(callback_type)
      callback_class = "#{callback_type.camelize}Callback"
      callback_file  = "callback/#{callback_type}_callback"

      begin
        instantiate_callback callback_file, callback_class, callback_type
      rescue LoadError => error
        if @@allowed_payneteasy_callback_types.include? callback_type
          instantiate_callback 'callback/paynet_easy_callback', 'PaynetEasyCallback', callback_type
        else
          raise error
        end
      end
    end
def callback(callback_type)
      callback_class = "#{callback_type.camelize}Callback"
      callback_file  = "callback/#{callback_type}_callback"

      begin
        instantiate_callback callback_file, callback_class, callback_type
      rescue LoadError => error
        if @@allowed_payneteasy_callback_types.include? callback_type
          instantiate_callback 'callback/paynet_easy_callback', 'PaynetEasyCallback', callback_type
        else
          raise error
        end
      end
    end
Get callback processor by callback type

 @param    callback_type   [String]              Callback type

 @return                   [CallbackPrototype]   Callback processor