#
#--
# Copyright (c) 2006-2007, 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 
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# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
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#++
#
# $Id: definitions.rb 2725 2006-06-02 13:26:32Z jmettraux $
#

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

require 'openwfe/participants/participant'


#
# some base participant implementations
#
module OpenWFE

    #
    # The PrintParticipant will just emit its name to the
    # test tracer if any or to stdout else.
    # Used by some unit tests.
    #
    class PrintParticipant 
        include LocalParticipant

        def consume (workitem)

            tracer = @application_context['__tracer']

            if tracer
                tracer << workitem.participant_name
            else
                puts workitem.participant_name
            end

            reply_to_engine(workitem)
        end
    end

    #
    # This participant is used by the register_participant() method of
    # Engine class.
    #
    #     engine.register_participant("the_boss") do |workitem|
    #         puts "the boss received a workitem"
    #     end
    #
    # After the block executes, the BlockParticipant immediately replies
    # to the engine.
    #
    # You can pass a block with two arguments : flow_expression and workitem
    # to BlockParticipant, it will automatically adapt.
    #
    #     engine.register_participant("the_boss") do |fexp, wi|
    #         puts "the boss received a workitem from exp #{fexp.fei.to_s}"
    #     end
    #
    # Having the FlowExpression instance at hand allows for advanced tricks,
    # beware...
    #
    class BlockParticipant 
        include LocalParticipant

        def initialize (block0=nil, &block1)
            @block = if block1
                block1
            else
                block0
            end
            raise "Missing a block parameter" \
                unless @block
        end

        def consume (workitem)

            if @block.arity == 1
                @block.call workitem
            elsif @block.arity > 1
                @block.call get_flow_expression(workitem), workitem
            else
                @block.call
            end

            reply_to_engine(workitem) \
                if workitem.kind_of? InFlowWorkItem
            # else it's a cancel item
        end
    end

end