#!/usr/bin/python3
# -*- coding: utf-8 -*-
#
# Univention UCS@school
# Copyright 2016-2021 Univention GmbH
#
# https://www.univention.de/
#
# All rights reserved.
#
# The source code of this program is made available
# under the terms of the GNU Affero General Public License version 3
# (GNU AGPL V3) as published by the Free Software Foundation.
#
# Binary versions of this program provided by Univention to you as
# well as other copyrighted, protected or trademarked materials like
# Logos, graphics, fonts, specific documentations and configurations,
# cryptographic keys etc. are subject to a license agreement between
# you and Univention and not subject to the GNU AGPL V3.
#
# In the case you use this program under the terms of the GNU AGPL V3,
# the program is provided 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public
# License with the Debian GNU/Linux or Univention distribution in file
# /usr/share/common-licenses/AGPL-3; if not, see
# <http://www.gnu.org/licenses/>.
"""
Singleton to the factory currently in use.
"""
import importlib
from typing import TYPE_CHECKING, Optional, Type
from .exceptions import InitialisationError
if TYPE_CHECKING:
from .default_user_import_factory import DefaultUserImportFactory
[docs]def setup_factory(factory_cls_name): # type: (str) -> DefaultUserImportFactory
"""
Create import factory.
:param str factory_cls_name: full dotted name of class
:return: Factory object
:rtype: Factory
"""
fac_class = load_class(factory_cls_name)
factory = Factory(fac_class()) # type: DefaultUserImportFactory
return factory
[docs]def load_class(dotted_class_name): # type: (str) -> type
"""
Load class from its full dotted name.
:param dotted_class_name: str: full dotted name of class
:return: class
:rtype: type
"""
module_path, _, class_name = dotted_class_name.rpartition(".")
module = importlib.import_module(module_path)
return getattr(module, class_name)
[docs]class Factory(object):
"""
Singleton to the global abstract factory object.
"""
class __SingleFac:
def __init__(self, factory): # type: (Optional[DefaultUserImportFactory]) -> None
if not factory:
raise InitialisationError("Concrete factory not yet configured.")
self.factory = factory
_instance = None # type: __SingleFac
def __new__(cls, factory=None):
# type: (Type[Factory], Optional[DefaultUserImportFactory]) -> DefaultUserImportFactory
if not cls._instance:
cls._instance = cls.__SingleFac(factory)
return cls._instance.factory
