How to set modification date every time NSManagedObject changes?

Question

Every time one of my managed objects is modified, I want to store the date it was modified (in an attribute which is already in my data model), for convenience when I'm syncing with other clients.

Is there a way to do this without A) re-writing all my setters manually or B) relying on myself to always change the modification date every single time the object is modified?

Answer 1

You could register with the notification center to observe the NSManagedObjectContextObjectsDidChange notification.

This will tell you what objects are changed. You can check to see if your object is among them and take action accordingly.

Answer 2

Just for completeness, you can also do this in -willSave if you already have a subclass of NSManagedObject.