factory_method.py

# -*- coding utf-8 -*-

"""http://ginstrom.com/scribbles/2007/10/08/design-patterns-python-style/"""

class JapaneseGetter:
	"""A simple localizer a la gettext"""
	def __init__(self):
		self.trans = dict(dog="犬", cat="猫")

	def get(self, msgid):
		"""We'll punt if we don't have a translation"""
		try:
			return self.trans[msgid]
		except KeyError:
			return str(msgid)


class EnglishGetter:
	"""Simply echoes the msg ids"""
	def get(self, msgid):
		return str(msgid)


def get_localizer(language="English"):
	"""The factory method"""
	languages = dict(English=EnglishGetter, Japanese=JapaneseGetter)
	return languages[language]()

# Create our localizers
e, g = get_localizer("English"), get_localizer("Japanese")
for msgid in "dog parrot cat bear".split():
	print(e.get(msgid), g.get(msgid))