Creation Date: Feb 25, 1998
Keywords: EOF, NSMutableArray, Notifications, Performance
This document describes a problem that can cause memory leaks and slow performance for OPENSTEP applications. The problem occurs because Apple's EOF framework uses a category to add an addObjectIfAbsent: method to NSMutableArray.
@interface NSMutableArray (EOPointerBasedManipulation)
// adds an object to the array if and only if it isn't already in the array
// return YES if object was not in the array or NO if it already was present
Because this method is not documented, some Apple developers and writers of third-party frameworks have added their own addObjectIfAbsent: method. When EOF's EOObjectStoreCoordinator makes a call to addObjectIfAbsent: to register a notification, it does not receive the expected return value, and two additional notifications are generated. This can seriously affect system performance in applications which make a large number of database fetches. There are three possible solutions to the problem:
--Modify your implementation of the method to return the appropriate values, as shown above
--Modify your code to use Apple's implementation of this method
--Change the name of your custom method so Apple's implementation is not superceded.