StackOverflow2013

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POObjective-C Getter Memory Management
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copied!<p>I'm fairly new to Objective-C and am not sure how to correctly deal with memory management in the following scenario:</p> <p>I have a Core Data Entity with a to-many relationship for the key "children". In order to access the children as an array, sorted by the column "position", I wrote the model class this way:</p> <pre><code>@interface AbstractItem : NSManagedObject { NSArray * arrangedChildren; } @property (nonatomic, retain) NSSet * children; @property (nonatomic, retain) NSNumber * position; @property (nonatomic, retain) NSArray * arrangedChildren; @end @implementation AbstractItem @dynamic children; @dynamic position; @synthesize arrangedChildren; - (NSArray*)arrangedChildren { NSArray* unarrangedChildren = [[self.children allObjects] retain]; NSSortDescriptor* sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"position" ascending:YES]; [arrangedChildren release]; arrangedChildren = [unarrangedChildren sortedArrayUsingDescriptors:[NSArray arrayWithObject:sortDescriptor]]; [sortDescriptor release]; [unarrangedChildren release]; return [arrangedChildren retain]; } @end </code></pre> <p>I'm not sure whether or not to retain unarrangedChildren and the returned arrangedChildren (first and last line of the arrangedChildren getter). Does the NSSet allObjects method already return a retained array? It's probably too late and I have a coffee overdose.</p> <p>I'd be really thankful if someone could point me in the right direction. I guess I'm missing vital parts of memory management knowledge and I will definitely look into it thoroughly.</p>

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