Rails - Apr 2006 - Why no call to Model.new on find?

I created a model with some internal state derived from a combination of 
database and non-database data. Since I wanted to calculate these values 
once rather than every time they''re requested by the view, I calculated
them in the initialize method and set some instance variables. However, 
I soon noticed that these values weren''t getting set when I retrieved 
data using the Model.find methods. After looking around the source 
(specifically ActiveRecord::Base.instantiate), I see that Model.new is 
never called. Rather, the allocate method is used and so the initialize 
method I''ve defined is never called.

Why is it done this way? What would be the more appropriate way to 
achieve the functionality I''m looking for?

-- 
Posted via http://www.ruby-forum.com/.

On 4/4/06, Jon Bauman <jonrubyforum@shumi.org>
wrote:
> I created a model with some internal state derived from a combination of
> database and non-database data. Since I wanted to calculate these values
> once rather than every time they''re requested by the view, I
calculated
> them in the initialize method and set some instance variables. However,
> I soon noticed that these values weren''t getting set when I
retrieved
> data using the Model.find methods. After looking around the source
> (specifically ActiveRecord::Base.instantiate), I see that Model.new is
> never called. Rather, the allocate method is used and so the initialize
> method I''ve defined is never called.
>
> Why is it done this way? What would be the more appropriate way to
> achieve the functionality I''m looking for?
after_find or after_initialize may work for you. See ActiveRecord::Callbacks.

-Isak