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# -*- coding: utf-8 -*-
# Copyright © 2007-2008 Stockholm TreeAligner Project
# Author: Torsten Marek <shlomme@gmx.net>
# Licensed under the GNU GPLv2
class MissingClassException(Exception):
pass
class FactoryBase(object):
__classes__ = []
def __init__(self):
self._switch = {}
if isinstance(self.__classes__, dict):
self._switch = self.__classes__
else:
for cls in self.__classes__:
for switch in self._get_class_switch(cls):
self._switch[switch] = cls
def create(self, *args):
switch_value = self._get_switch(*args)
try:
cls = self._switch[switch_value]
except KeyError, e:
self.raise_error(e.args[0])
return self._create_instance(cls, *args)
def raise_error(self, switch_name):
raise MissingClassException, switch_name
def _create_instance(self, cls, *args):
return cls(*args)
def _get_class_switch(self, cls):
raise NotImplementedError
def _get_switch(self, *args):
raise NotImplementedError
def __iter__(self):
return iter(set(self._switch.values()))
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