Fixes #79 (and brokes tests of xml translator)

Adding a field to all non abstract classes to store in DB the name of corresponding LeObject subclass

em_test.py

                         data_handler = 'datetime',
                         now_on_update = True,
 )
-em_object.new_field(    'classname',
-                        display_name = 'Class name',
-                        group = base_group,
-                        data_handler = 'varchar',
-                        immutable = True
-)
 
 ########################
 # Lodel old classtypes #
     help_text = {'eng': 'Abstract class common to each Index classes'},
     abstract = True,
     group = index_group,
-    datasource = 'dummy2',
+    datasources = 'dummy2',
     parents = em_object)
 
 index_name = index_abstract.new_field(
         'eng': 'Thematic index',
         'fre': 'Index thématique'},
     group = index_group,
-    datasource = 'dummy2',
+    datasources = 'dummy2',
     parents = index_abstract)
 
 index_theme_theme = index_abstract.new_field(

lodel/editorial_model/components.py

 from lodel.utils.mlstring import MlString
 
 from lodel.editorial_model.exceptions import *
+from lodel.leapi.leobject import CLASS_ID_FIELDNAME
 
 ##@brief Abstract class to represent editorial model components
 # @see EmClass EmField
         self.parents = parents
         ##@brief Stores EmFields instances indexed by field uid
         self.__fields = dict() 
+        
+        #Adding common field
+        if not self.abstract:
+            self.new_field(
+                CLASS_ID_FIELDNAME,
+                display_name = {
+                    'eng': "LeObject subclass identifier",
+                    'fre': "Identifiant de la class fille de LeObject"},
+                help_text = {
+                    'eng': "Allow to create instance of the good class when\
+ fetching arbitrary datas from DB"},
+                data_handler = 'LeobjectSubclassIdentifier',
+                internal = True)
     
     ##@brief Property that represent a dict of all fields (the EmField defined in this class and all its parents)
     # @todo use Settings.editorialmodel.groups to determine wich fields should be returned
     # @todo use Settings.editorialmodel.groups to determine wich fields should be returned
     def fields(self, uid = None, no_parents = False):
         fields = self.__fields if no_parents else self.__all_fields
+        if CLASS_ID_FIELDNAME in fields:
+            del(fields[CLASS_ID_FIELDNAME])
         try:
             return list(fields.values()) if uid is None else fields[uid]
         except KeyError:

lodel/leapi/datahandlers/datas.py

 
     def _check_data_value(self, value):
         return value, None
+
+class LeobjectSubclassIdentifier(Varchar):
+    
+    help = 'Datahandler designed to handle LeObject subclass identifier in DB'
+    base_type = 'varchar'
+
+    def __init__(self, **kwargs):
+        if 'internal' in kwargs and not kwargs['internal']:
+            raise RuntimeError(self.__class__.__name__+" datahandler can only \
+be internal")
+        kwargs['internal'] = True
+        super().__init__(**kwargs)
+
+    def _check_data_consistency(self, emcomponent, fname, datas):
+        datas[fname] = emcomponent.__class__.__name__

lodel/leapi/leobject.py

 from lodel.settings import Settings
 from lodel.settings.utils import SettingsError
 
+##@brief Stores the name of the field present in each LeObject that indicates
+#the name of LeObject subclass represented by this object
+CLASS_ID_FIELDNAME = "classname"
+
 class LeApiErrors(Exception):
     ##@brief Instanciate a new exceptions handling multiple exceptions
     # @param msg str : Exception message

tests/editorial_model/test_model.py

         grp2 = model.new_group('testgroup2')
         grp2.add_components((cls2, c1f2, c2f1, c2f2))
         grp2.add_dependencie(grp1)
-        e_hash = 0x476f5917265b6fbd06d94b81f4e9b402
+        e_hash = 0x250eab75e782e51bbf212f47c6159571
         self.assertEqual(model.d_hash(), e_hash)
 
         c2f1.uid = 'foobar'