#
#--
# 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.
#++
#
# $Id: definitions.rb 2725 2006-06-02 13:26:32Z jmettraux $
#

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

require 'openwfe/expressions/filter'


module OpenWFE

  #
  # This expression applies a filter to the workitem used by the process
  # segment nested within it.
  #
  #   class TestFilter48a0 < ProcessDefinition
  #     sequence do
  #
  #       set :field => "readable", :value => "bible"
  #       set :field => "writable", :value => "sand"
  #       set :field => "randw", :value => "notebook"
  #       set :field => "hidden", :value => "playboy"
  #
  #       alice
  #
  #       filter :name => "filter0" do
  #         sequence do
  #           bob
  #           charly
  #         end
  #       end
  #
  #       doug
  #     end
  #
  #     filter_definition :name => "filter0" do
  #       field :regex => "readable", :permissions => "r"
  #       field :regex => "writable", :permissions => "w"
  #       field :regex => "randw", :permissions => "rw"
  #       field :regex => "hidden", :permissions => ""
  #     end
  #   end
  #
  # In this example, the filter 'filter0' is applied upon entering bob and
  # charly's sequence.
  #
  # Please note that the filter will not be enforced between bob and charly,
  # it is enforced just before entering the sequence and just after leaving
  # it.
  #
  # Note also that the ParticipantExpression accepts a 'filter' attribute,
  # thus :
  #
  #   <filter name="filter0">
  #     <participant ref="toto" />
  #   </filter>
  #
  # can be simplified to :
  #
  #   <participant ref="toto" filter="filter0" />
  #
  class FilterExpression < FlowExpression
    include FilterMixin

    names :filter

    attr_accessor :applied_workitem, :filter


    def apply workitem

      if @children.length < 1
        reply_to_parent workitem
        return
      end

      @applied_workitem = workitem.dup
      filter_in workitem, :name

      store_itself

      get_expression_pool.apply @children[0], workitem
    end

    def reply workitem

      filter_out workitem

      reply_to_parent workitem
    end
  end

end