As I said in my previous post, I need to override some AR accessor
methods. I thought that alias_method would work, it didn’t, I believe
because AR methods are invoked via method_missing. I thought
alias_attribute would work, but apparently that just makes a copy of the
accessor methods, so the original and the alias both point to the same
thing.
What I got to work was this - I need to get the object’s name, unless
it’s nil and the object is a child in acts_as_tree.
def name
if read_attribute(:name)
read_attribute(:name)
elsif read_attribute(:parent_id)
self.parent.name
end
end
def real_name
read_attribute(:name)
end
I don’t know if I need the real_name accessor, but either way it’s ugly
to write out a method like the name method for each of the 10 attributes
I need to do this with. Any suggestions would be much appreciated.
Right on - I was thinking along those lines on the way home from work.
I’ve
never really done any programming of this type(is this
meta-programming?),
but I think I’m going to try for something like this:
defaults_to_parent :attr_1, :attr_2, :attr_3
I’ll post back if I get anything in case anyone else needs something
like
this.
Right on - I was thinking along those lines on the way home from
work. I’ve never really done any programming of this type(is this
meta-programming?), but I think I’m going to try for something
like this:
defaults_to_parent :attr_1, :attr_2, :attr_3
I’ll post back if I get anything in case anyone else needs something
like this.
You can write something like this :
class MyModel < AR::B
def self.defaults_to_parent(*getters)
getters.each do |method|
class_eval(<<-EOM, FILE, LINE)
def #{method}
if read_attribute(:#{method})
read_attribute(:#{method})
elsif read_attribute(:parent_id)
self.parent.#{method}
end
end
EOM
end
end
Thank you , Jean-François. As far as I can tell, it works perfectly. If
my object has a nil attribute, it defaults to the parent, and if the
paren’t attribute is nil too, it returns nil. I’m not sure if I
understand, though, what FILE and LINE do.
OK, those params are just for error reporting. I was thinking I would
have to use eval, I didn’t know about class_eval and it probably would
have taken me awhile to figure it out. Your help is much appreciated.
Jason
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