#--
# Copyright (c) 2007-2009, John Mettraux, jmettraux@gmail.com
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# Made in Japan.
#++


require 'openwfe/logging'
require 'openwfe/workitem'
require 'openwfe/contextual'


module OpenWFE

  #
  # this mixin module provides two protected methods, handle_item() and
  # filter_item(). They can be easily overriden to add some special
  # behaviours.
  #
  module WorkItemListener

    include Contextual
    include Logging
    include OwfeServiceLocator

    protected

    #
    # Simply considers the object as a workitem and feeds it to the
    # engine.
    #
    def handle_item (item)

      filter_items(item)

      get_engine.reply(item)
    end

    #
    # The base implementation is just empty, feel free to override it
    # if you need to filter workitems.
    #
    # One example :
    #
    #   class MyListener
    #     include WorkItemListener
    #
    #     protected
    #
    #       #
    #       # MyListener doesn't accept launchitems
    #       #
    #       def filter_items (item)
    #         raise "launchitems not allowed" \
    #           if item.is_a?(OpenWFE::LaunchItem)
    #       end
    #   end
    #
    def filter_items (item)

      #raise(
      #  "listener of class '#{self.class.name}' "+
      #  "doesn't accept launchitems")
    end
  end

end