class Klass1:
""" a very simple obj """
def __init__(self):
pass
def hi(self):
print 'hi'
class Factory:
""" base factory that can construct objects in a variety of ways:
* modules ['package1.subpackage',] to be searched for klass
* search global namespace
* create takes a arguement of what type of class to return
* return a default implementation - subclass must define createDefault()
"""
def __init__(self, modules=[]):
self.modules=modules
def createDefault(self):
print dir()
raise NotImplementedError
def create(self, klass=None):
import string
if klass in globals().keys():
if type(globals()[klass]).__name__=='class':
return globals()[klass]()
for module in self.modules:
try:
fromlist = []
if string.find(module, '.'): fromlist = string.split(module, '.')[:-1]
module = __import__(module, globals(), locals(), fromlist)
if hasattr(module, klass): return getattr(module, klass)()
except AttributeError: pass
return self.createDefault()
class MyFactory(Factory):
""" concrete factory that specifies:
* what modules to search for
* implements a createDefault() - which is used if class isnt found
"""
def __init__(self, modules=[]):
Factory.__init__(self,modules)
def createDefault(self):
return Klass1()
#--------much simpler one by mark lutz, http://shell.rmi.net/~lutz/talk.html
def factory(aClass, *args): # varargs tuple
return apply(aClass, args) # call aClass
class Spam:
def doit(self, message):
print message
class Person:
def __init__(self, name, job):
self.name = name
self.job = job
object1 = factory(Spam)
object2 = factory(Person, "Guido", "guru")
