--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/pyams_security/index.py	Wed Jun 17 09:59:18 2015 +0200
@@ -0,0 +1,36 @@
+#
+# Copyright (c) 2008-2015 Thierry Florac <tflorac AT ulthar.net>
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+
+__docformat__ = 'restructuredtext'
+
+
+# import standard library
+
+# import interfaces
+from pyams_security.interfaces import IProtectedObject
+
+# import packages
+from hypatia.keyword import KeywordIndex
+
+
+class PrincipalsRoleIndex(KeywordIndex):
+    """Principals role index"""
+
+    def __init__(self, role_id, family=None):
+        KeywordIndex.__init__(self, role_id, family)
+        self.role_id = role_id
+
+    def discriminate(self, obj, default):
+        protected_object = IProtectedObject(obj, None)
+        if protected_object is None:
+            return default
+        return protected_object.get_principals(self.role_id)