#
#--
# Copyright (c) 2007-2008, 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
#

module OpenWFE

    #
    # The methods of the engine for updating live expressions
    # (in flight modifications of process instances)
    #
    module UpdateExpMethods

        #
        # Use only when doing "process gardening".
        #
        # This method updates an expression, the 'data' parameter is expected 
        # to be a hash. If the expression is an Environment, the variables
        # will be merged with the ones found in the data param.
        # If the expression is not an Environment, the data will be merged
        # into the 'applied_workitem' if any.
        #
        # If the merge is not possible, an exception will be raised.
        #
        def update_expression_data (fei, data)

            fexp = fetch_exp fei

            original = if fexp.is_a?(Environment)

                fexp.variables
            else

                fexp.applied_workitem.attributes
            end

            original.merge! data

            get_expression_pool.update fexp
        end

        #
        # A variant of update_expression() that directly replaces
        # the raw representation stored within a RawExpression.
        #
        # Useful for modifying [not yet reached] segments of processes.
        #
        def update_raw_expression (fei, representation)

            fexp = fetch_exp fei

            raise "cannot update already applied expression" \
                unless fexp.is_a?(RawExpression)

            fexp.raw_representation = representation
            fexp.raw_rep_updated = true

            get_expression_pool.update fexp
        end

        #
        # Replaces an expression in the pool with a newer version of it.
        #
        # (useful when fixing processes on the fly)
        #
        def update_expression (fexp)

            fexp.application_context = application_context

            fexp.raw_rep_updated = true

            get_expression_pool.update fexp
        end

    end

end