On 2013-06-19, at 3:21 AM, Rick Mann <[email protected]> wrote: > > On Jun 18, 2013, at 22:42 , Dave Fernandes <[email protected]> wrote: > >> The foolproof way to do it is to have the transient attributes recalculated >> each time they are accessed. In other words, they are simply getter methods. >> But if they are expensive to compute, this might not work well. If you are >> using bindings or KVO, you then have a class method + >> (NSSet*)keyPathsForValuesAffecting<AttributeName> that ensures observers of >> the transient attribute are notified when underlying non-transient >> attributes change. > > In this case, it's not accessed terribly frequently, so that's what I ended > up doing. I do use KVO a lot, although I don't see how that helps in this > case (to trigger re-computing the transient value).
It's not useful if you want to pre-compute and cache the transient values. It is just useful if the transient is a getter, and you need to notify the observers. > > Pity there's not an update method that can be overridden in > NSManagedObjectSubclasses when this happens. I guess my objects could KVO > themselves… > > -- > Rick > > > _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
