Re: Overridding -[NSPersistentDocument managedObjectContext]
Re: Overridding -[NSPersistentDocument managedObjectContext]
- Subject: Re: Overridding -[NSPersistentDocument managedObjectContext]
- From: Andy Lee <email@hidden>
- Date: Mon, 27 Oct 2008 15:40:47 -0400
On Oct 27, 2008, at 3:25 PM, Ron Lue-Sang wrote:
On Oct 27, 2008, at 10:49 AM, Jerry Krinock wrote:
So it seems like I need to instead use my own instance variable,
myMOC. Something like this should work:
- (NSManagedObjectContext*)managedObjectContext {
if (![self myMOC]) {
NSManagedObjectContext* newMOC ;
//
// ... code to alloc, initialize and configure newMOC
//
[self setMyMOC:newMOC] ;
[myMOC release] ;
}
return [self myMOC] ;
}
But it seems odd that now super's instance variable
managedObjectContext will just sit there forever, pointing to nil.
Is this the proper intended usage?
Yes, that's the intended usage. Use your own storage or call super.
Should he also override -setManagedObjectContext:?
My 2 cents: this seems like a brittle design -- it expects the
overrider to know that the superclass never uses the ivar directly
except in accessors, and it expects the implementer of the base class
to remember never to use the ivar directly. In any case, I think the
documentation could be clearer and I'll send feedback to that effect.
--Andy
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