I'm having some trouble with some seemingly basic OO stuff with one of my AR::Base descendants. I ended up creating a custom initialize method that takes two parameters - an integer and the standard AR attributes hash, like so: def initialize(user_id, attributes = nil) In another part of my application, I was calling "clone" on one of these objects and it gave me an incorrect number of arguments error. I figured out it was because of the fact that my initialize expects 1 argument no matter what. As soon as I provided a default value for user_id in the argument list above, the call to clone was fine - I assume since now my initialization didn't require any arguments at all. But this is somewhat disturbing. I was under the impression that I would still have access to the regular initialize(attributes = nil) method that I get from ActiveRecord::Base. Why is it not available? Doesn't this imply that I can't have multiple constructors for an AR object? I tried to add def initialize(attributes = nil) super end to my object and I still can't instantiate it just running "new" (no arguments). What gives? Thanks for any help. Wes
on 2007-01-04 22:42
on 2007-01-04 23:14
Use the :after_initialize callback (or one of the other AR callbacks) rather than trying to override the initialize method. This is the recommended Rails approach.
on 2007-01-05 01:06
Thanks Mick. I'm aware of the after_initialize method, but I just keep forgetting that ActiveRecord objects don't behave like normal objects. "Least surprise" my a** :). Strictly speaking, I suppose, Ruby is "least surprise", Rails is "opinionated." :) But don't get me wrong, I really dig ActiveRecord. Still, it's weird to me that the existence of a method (initialize in this case) seem to preclude any polymorphism on that method. Wes
on 2007-01-05 07:28
Mick Sharpe wrote: > Use the :after_initialize callback (or one of the other AR callbacks) > rather than trying to override the initialize method. This is the > recommended Rails approach. You can also use super def initialize(foo, *args) @foo = foo super(*args) end The super method calls the same method as defined in the parent class. This let's you override a method, and still call the original method.
on 2007-01-05 07:43
Alex Wayne wrote: > You can also use super > > def initialize(foo, *args) > @foo = foo > super(*args) > end > This is what I was doing. If you do this and then attempt to call clone on your AR::Base descendant, it will complain. Wes
on 2007-01-06 19:30
Just a quick glance as I'm out the door, but don't you mean this to be a class method IE self.initialize? Jason
on 2007-01-15 20:45
I now know that there is no method overloading within the context of one class due to the dynamic nature of Ruby. So I get it. Wes