On 9/9/05, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> I want it so that I can do some model specific object composition after
> it loads from the db, ie if field 'type' is set to XXX then instantiate
> and attach a XXXHandler and if it's set YYY then instantiate a
> YYYHandler.
Generally, that sort of stuff can be accomplished with custom model
methods. Just do something like this:
class Foo(meta.Model):
# ....
def get_handler(self):
if self.type == 'XXX':
return XXXHandler()
elif self.type == 'YYY':
return YYYHandler()
For performance, you can cache the result on a per-instance basis:
class Foo(meta.Model):
# ....
def get_handler(self):
try:
return self._handler_cache
except AttributeError:
if self.type == 'XXX':
handler = XXXHandler()
elif self.type == 'YYY':
handler = return YYYHandler()
self._handler_cache = handler
return handler
> Also, while I am at it, what is the "django-ish" way to subclass models
> and have subclasses come out on the load? This is the inheritance (as
> opposed to composition) approach which is not appropriate in this case
> but might be in another one.
I'm not sure exactly what you mean, but have you seen this?
http://www.djangoproject.com/documentation/models/subclassing/
Adrian
--
Adrian Holovaty
holovaty.com | djangoproject.com | chicagocrime.org
