diff --git a/product/ERP5/mixin/movement_generator.py b/product/ERP5/mixin/movement_generator.py
new file mode 100644
index 0000000000000000000000000000000000000000..22628e9c21711218c30503b3b4ff3fd1e7e387e4
--- /dev/null
+++ b/product/ERP5/mixin/movement_generator.py
@@ -0,0 +1,134 @@
+# -*- coding: utf-8 -*-
+##############################################################################
+#
+# Copyright (c) 2010 Nexedi SA and Contributors. All Rights Reserved.
+#
+# WARNING: This program as such is intended to be used by professional
+# programmers who take the whole responsibility of assessing all potential
+# consequences resulting from its eventual inadequacies and bugs
+# End users who are looking for a ready-to-use solution with commercial
+# guarantees and support are strongly adviced to contract a Free Software
+# Service Company
+#
+# This program is Free Software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+#
+##############################################################################
+
+from Products.ERP5.MovementCollectionDiff import _getPropertyAndCategoryList
+
+class MovementGeneratorMixin:
+  """Movement Generator interface specification
+
+  Documents which implement IMovementGenerator
+  can be used to generate an IMovementList from
+  an existing IMovementCollection, IMovementList or
+  IMovement. Typical IMovementGenerator are Rules
+  and Trade Conditions.
+  """
+
+  # Implementation of IMovementGenerator
+  def getGeneratedMovementList(context, movement_list=None, rounding=False):
+    """
+    Returns an IMovementList generated by a model applied to the context
+
+    context - an IMovementCollection, an IMovementList or an IMovement
+
+    movement_list - optional IMovementList which can be passed explicitely
+                    whenever context is an IMovementCollection and whenever
+                    we want to filter context.getMovementList
+
+    rounding - boolean argument, which controls if rounding shall be applied on
+               generated movements or not
+
+    NOTE:
+      - implement rounding appropriately (True or False seems
+        simplistic)
+    """
+    raise NotImplementedError
+
+  def _getInputMovementAndPathTupleList(self, context):
+    """Returns list of tuples (movement, business_path)"""
+    input_movement_list = self._getInputMovementList(context)
+    business_process = context.getBusinessProcessValue()
+
+    # In non-BPM case, we have no business path.
+    if business_process is None:
+      return [(input_movement, None) for input_movement in input_movement_list]
+
+    input_movement_and_path_list = []
+    business_path_list = []
+    trade_phase_list = context.getSpecialiseValue().getTradePhaseList()
+    for input_movement in input_movement_list:
+      for business_path in business_process.getPathValueList(
+                          trade_phase_list,
+                          input_movement):
+        input_movement_and_path_list.append((input_movement, business_path))
+        business_path not in business_path_list and business_path_list \
+            .append(business_path)
+
+    if len(business_path_list) > 1:
+      raise NotImplementedError
+
+    return input_movement_and_path_list
+
+  def _getInputMovementList(self, context):
+    raise NotImplementedError
+
+  def _getPropertyAndCategoryList(self, movement, business_path):
+    property_dict = _getPropertyAndCategoryList(movement)
+
+    if business_path is None:
+      return property_dict
+
+    # Arrow
+    for base_category in \
+        business_path.getSourceArrowBaseCategoryList() +\
+        business_path.getDestinationArrowBaseCategoryList():
+      # XXX: we need to use _list for categories *always*
+      category_url = business_path.getDefaultAcquiredCategoryMembership(
+          base_category, context=movement)
+      if category_url not in ['', None]:
+        property_dict['%s_list' % base_category] = [category_url]
+      else:
+        property_dict['%s_list' % base_category] = []
+    # Amount
+    if business_path.getQuantity():
+      property_dict['quantity'] = business_path.getQuantity()
+    elif business_path.getEfficiency():
+      property_dict['quantity'] = movement.getQuantity() *\
+        business_path.getEfficiency()
+    else:
+      property_dict['quantity'] = movement.getQuantity()
+
+    if movement.getStartDate() == movement.getStopDate():
+      property_dict['start_date'] = business_path.getExpectedStartDate(
+          movement)
+      property_dict['stop_date'] = business_path.getExpectedStopDate(movement)
+      # in case of not fully working BPM get dates from movement
+      # XXX: as soon as BPM will be fully operational this hack will not be
+      #      needed anymore
+      if property_dict['start_date'] is None:
+        property_dict['start_date'] = movement.getStartDate()
+      if property_dict['stop_date'] is None:
+        property_dict['stop_date'] = movement.getStopDate()
+    else: # XXX shall not be used, but business_path.getExpectedStart/StopDate
+          # do not works on second path...
+      property_dict['start_date'] = movement.getStartDate()
+      property_dict['stop_date'] = movement.getStopDate()
+
+    # save a relation to business path
+    property_dict['causality_list'] = [business_path.getRelativeUrl()]
+
+    return property_dict