#
#--
# Copyright (c) 2007, John Mettraux, OpenWFE.org
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# . Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.
#
# . Redistributions in binary form must reproduce the above copyright notice,
#   this list of conditions and the following disclaimer in the documentation
#   and/or other materials provided with the distribution.
#
# . Neither the name of the "OpenWFE" nor the names of its contributors may be
#   used to endorse or promote products derived from this software without
#   specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#++
#

#
# "made in Japan"
#
# John Mettraux at openwfe.org
#

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, Logging, 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