Rails - May 2007 - How can a polymorphic object check its own class type?

I have a polymorphic class and need to know the type from within the
model (for validation).
>From a controller, I can check instance[:type] to get the object''s
type, but how do I access this attribute from within the model?

If I check ''type'', I get a warning (and wrong value). Checking
''self.class'', just says ''Class''.

Thanks,
Amir


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helzer wrote:
> I have a polymorphic class and need to know the type from within the
> model (for validation).
>
> >From a controller, I can check instance[:type] to get the
object''s
> type, but how do I access this attribute from within the model?
>
> If I check ''type'', I get a warning (and wrong value).
Checking
> ''self.class'', just says ''Class''.
>
> Thanks,
> Amir
>
>
> >
>
>   
Not sure I''m quite understanding this correctly but hope this helps:

class ParentKlass < ActiveRecord::Base
end

class ChildKlass < ParentKlass

  def self.class_details
    puts "my class is #{self}" # self here IS the class
    puts "my base_class is #{self.base_class}" # gets the base class 
given a class
  end

  def class_details
    puts "my class is #{self.class}" # we''re asking for
details of the
instance''s class
    puts "my base_class is #{self.class.base_class}" # and then the
base
class of that class
  end

end

ChildKlass.class_details
# my class is ChildKlass
# my base_class is ParentKlass

ChildKlass.new.class_details
# my class is ChildKlass
# my base_class is ParentKlass

Cheers
Chris

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Hi Chris,

I tried to do that, but it didn''t work for me. My mistake was, I put
that code in the parent class. So whenever this code was called, it
reported the name of the parent and not the child.

Now that I''ve moved each case to the relevant child #{self} reports
the correct class name.

And, instead of writing complex class-dependent validation in the
parent class (which is inherently wrong to do), I now have simpler
validation in each child.

Thanks,
Amir


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