# Overriding one-to-many accessors

**URL:** <https://www.ruby-forum.com/t/overriding-one-to-many-accessors/86726>\
**Category:** Rails\
**Created:** [February 25, 2007, 3:48am UTC](https://www.ruby-forum.com/t/overriding-one-to-many-accessors/86726 "2007-02-25T03:48:54Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![glenatron](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/94ad74/32.png) [@glenatron](https://www.ruby-forum.com/u/glenatron)\
**Post date:** [February 25, 2007, 3:48am UTC](https://www.ruby-forum.com/t/overriding-one-to-many-accessors/86726/1 "2007-02-25T03:48:54Z")

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I have a Person that has\_many Things. I have defined a things method in  
Person so that I can do some special filtering.

However, elsewhere I am doing “person.things \<\< Thing.new…” and this  
is now broken. Which, of course makes sense, because my overriden things  
method just returns a filtered array of Thing objects… an array which  
has now lost any of the one-to-many magic that rails would provide in  
the original things method.

Any thoughts on dealing with this? Seems like I need to know what  
enhanced array is being returned by rails so I can do the same thing.

thanks,

b

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**Author:** ![glenatron](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/94ad74/32.png) [@glenatron](https://www.ruby-forum.com/u/glenatron)\
**Post date:** [February 26, 2007, 8:52pm UTC](https://www.ruby-forum.com/t/overriding-one-to-many-accessors/86726/2 "2007-02-26T20:52:53Z")

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Well, honestly the best thing I can come up with is, can you rename the  
Person.things function you are defining to do the filtering?  
So, instead do something like this  
def filtered\_things  
return self.things.collect {|x| }  
end  
and leave the original things function alone?  
It seems to me that your design is probably a bit skewed from what you  
want  
if you ALWAYS want the Person.things value to be filtered somehow…  
perhaps  
you are incorrectly defining the association… realize that you can put  
conditions and such on the definition of the association, so if you only  
wanted things with a status of 1, you could do  
has\_many :things, :conditions =\> ‘status = 1’  
If you can specify the conditions in this manner, then you could leave  
the  
things function to behave the way it normally does, filtering your  
results  
via the association, and leaving the things \<\< thing functionality open.

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<div class="post-metadata">

**Author:** ![glenatron](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/94ad74/32.png) [@glenatron](https://www.ruby-forum.com/u/glenatron)\
**Post date:** [February 27, 2007, 2:25am UTC](https://www.ruby-forum.com/t/overriding-one-to-many-accessors/86726/3 "2007-02-27T02:25:42Z")

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Hey, thanks for the answer… and that’s basically what I’ve done for  
now.

What the “filtering” actually is is combining the children of the  
current object with the children of the current object’s ancestors (yes,  
it’s acts\_as\_tree). So, it’s more a “building up” than a filtering.

This combined view is also the most commonly needed case, so I had  
wanted to redefine the accessor so we didn’t need to remember to use the  
“get-me-everything” version almost everywhere.

In fact, the other case – of just wanting the children of the current  
object without regard to its ancestors – has not really come up as a  
necessity yet.

I’ll get by with the alternately named method for now, but at some point  
I hope to come back to this… once I have a better understanding of the  
rails magic.

b

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<div class="post-metadata">

**Author:** ![glenatron](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/94ad74/32.png) [@glenatron](https://www.ruby-forum.com/u/glenatron)\
**Post date:** [February 27, 2007, 3:49pm UTC](https://www.ruby-forum.com/t/overriding-one-to-many-accessors/86726/4 "2007-02-27T15:49:02Z")

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Well, how about method aliasing?

def things\_with\_ancestors  
#your current implementation of things goes here  
end  
alias\_method :things\_original, :things  
alias\_method :things, :things\_with\_ancestors

Now you can do Person.things to get your normal stuff and  
Person.things\_original to get the original implementation of it (that  
works  
with \<\< and all that).

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<div class="post-metadata">

**Author:** ![glenatron](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/94ad74/32.png) [@glenatron](https://www.ruby-forum.com/u/glenatron)\
**Post date:** [February 27, 2007, 8:11pm UTC](https://www.ruby-forum.com/t/overriding-one-to-many-accessors/86726/5 "2007-02-27T20:11:17Z")

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Hmm, that sounds promising… will try it today.

b