"""
Authentication providers.

Because authentication providers are instantiated and configured in the application scope
(and not in the request handler), the authenticator implementations must be thread-safe.
"""
import abc
__authors__ = ['"Hans Lellelid" <hans@xmpl.org>']
__copyright__ = "Copyright 2009 Hans Lellelid"
__license__ = """Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
 
  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License."""

class Authenticator(object):
    """ Abstract base class for authenticators. """
    __metaclass__ = abc.ABCMeta
    
    @abc.abstractmethod
    def authenticate(self, login, passcode):
        """
        Authenticate the login and passcode.
         
        @return: Whether user is authenticated.
        @rtype: C{bool} 
        """