[Newbies] Proper object removal

Norbert Hartl norbert at hartl.name
Wed Jun 4 07:55:11 UTC 2008

On Wed, 2008-06-04 at 00:04 -0400, Rob Rothwell wrote:
> Hello,
> After much help already, I think I need some training in proper object
> removal.
> When my application creates an object and stores it in an
> OrderedCollection, and than wants to delete it, I am trying to do so
> quite explicitly with something like:
> DataManager>>deleteSelectedAbstractors
>     self selected do: [:each |
>         self abstractors remove: each.
>         each := nil.
>     ]
> which removes the object from my application (it's collection), and
> yet when I look for my object in the system with

> DataAbstractor allInstances.
> I still see the object I removed, even with an explicit Smalltalk
> garbageCollect or garbageCollectMost.  Anything I create just seems to
> hang around forever.
> Any help understanding what I need to do to make sure my objects
> really go away when I am done with them would be greatly appreciated!

The objects are still referenced in the collection you get 
from self selected. The line with "each := nil" is useless
as each is only a temporary variable. I assume that you want
to empty the selected collection as well. you could do

   self selected copy do: [:each |       
   self abstractors remove: each.
   self selected remove: each.



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