Adds LeQuery.is_exist function to test the existence of an LeObject instance

lodel/leapi/query.py

     'lodel.plugin.hooks': ['LodelHook'],
     'lodel.logger': ['logger']})
 
+##@brief Tool to check if a target_class's object exists and is stored
+#@param target_class : class where the object is supposed to be
+#@param uid : a unique id in target_class
+#@returns true if an object with unique id uid exists in target_class, false if not
+def is_exist(target_class, uid):
+	from .leobject import LeObject
+	if not inspect.isclass(target_class) or not issubclass(target_class, LeObject):
+		raise TypeError("target class has to be a child class of LeObject but %s was given"% target_class)
+	datasource = target_class._ro_datasource
+	return datasource.is_exist(target_class,uid)
+
 
 ##@todo check datas when running query
 class LeQuery(object):

lodel/plugins/mongodb_datasource/datasource.py

-# -*- coding: utf-8 -*-
+object# -*- coding: utf-8 -*-
 
 import re
 import warnings
                 #with sets
                 datas[dname] = list(datas[dname])
         return datas
+
+    ##@brief Tool to check if a record with unique id uid is set in the target_class representation
+    #@param target_class : class to check in 
+    #@param uid : a unique id in target_class
+    #@returns true if a record with unique id uid exists in the target_class representation, false if not
+    def is_exist(self, target_class, uid):
+    # retrouver la table qui correspond à target_class
+    # vérifier qu'il existe, ou pas, un enregistrement contenant uid
+        result = self.select(self, target_class, [target_class.uid_fieldname], filters = [(target_class.uid_fieldname, '=', uid)])
+        return len(result) == 1