On 2009 Feb 25, at 17:11, Ben Trumbull wrote:
bug numbers ?
Ben, I will definitely file bug(s) after I get this sorted out. But in the interim...
The problem is easily stated in terms of DepartmentAndEmployees. I have views which want to know when various object properties change. For one example, say I want to add an OrgChart object. My OrgChart wants to receive a notification or observation when the directReports of any Employee is changed.
There appear to be solutions to this problem and both are surprisingly complicated.
Solution 1. Use KVO. Although adding observers is systematic (awakeFromInsert + awakeFromFetch), removing observers must be done (1) when deallocating the moc and (2) in the managed object's -dealloc method (which is not recommended for subclassing). The latter is to catch objects still on the undo stack or elsewhere.
Solution 2. Use Custom Setters. In each setter, post a notification. This is not too bad with attributes -- only one setter per attribute. But for to-many relations you need to override the four, or is it five, set mutator methods, and what if more are added in some future version of Mac OS? This requires much code and seems fragile.
Which solution, or a different one, looks "better" to you? Thank you, Jerry _______________________________________________ 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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
