#
#--
# Copyright (c) 2006-2008, 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/expressions/flowexpression'


module OpenWFE

    #
    # Triggers the first (and supposedly unique child of this expression)
    # but never wait for its reply (lose it).
    #
    # A 'lose' expression never replies to its parent expression.
    #
    #     <lose>
    #         <participant ref="toto" />
    #     </lose>
    #
    # Useful only some special process cases (like a concurrence
    # expecting only a certain number of replies).
    #
    # The brother expressions is 'forget', but 'forget' triggers its child
    # and immediately replies, whereas 'lose' doesn't reply.
    #
    class LoseExpression < FlowExpression

        names :lose

        def apply (workitem)

            get_expression_pool.apply(children[0], workitem) \
                if (@children and @children.length > 0)
        end

        def reply (workitem)

            get_expression_pool.remove self
        end
    end

    #
    # This expression triggers its child (in its own thread) and then
    # forgets about it. It immediately replies to its parent expression.
    #
    # The brother expression 'lose' triggers its child but never replies to its
    # parent expression.
    # 
    # The 'forget' expression is useful for triggering process segments
    # that are, well, dead ends.
    #
    class ForgetExpression < FlowExpression

        names :forget

        def apply (workitem)

            if (@children and @children.length > 0)

                wi = workitem.dup

                child = @children[0]
                get_expression_pool.forget self, child
                get_expression_pool.apply child, wi
            end

            reply_to_parent workitem
        end

        def reply (workitem)
            # never gets called
        end
    end

end