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copied!<p>I've written a couple of helper methods (see below) to break the retain loops for a whole graph of objects by using introspection of the Entity model. You can use it after receiving a memory warning notification to release any memory held by the part of your core data model accessible through that particular object. </p> <pre><code>@interface CoreDataHelper(Private) + (void)faultObjectImpl:(NSManagedObject *)managedObject mergeChanges:(FaultChangeBehaviour)mergeChanges; + (void)faultObjectGraphForObject:(NSManagedObject *)managedObject handledObjects:(NSMutableArray *)handledObjects mergeChanges:(FaultChangeBehaviour)mergeChanges; @end @implementation CoreDataHelper typedef enum FaultChangeBehaviour { FaultChangeBehaviourIgnore, FaultChangeBehaviourReapply, FaultChangeBehaviourMerge } FaultChangeBehaviour; + (void)faultObjectGraphForObject:(NSManagedObject *)managedObject keepChanges:(BOOL)keepChanges { NSMutableArray *handledObjects = [NSMutableArray arrayWithCapacity:64]; FaultChangeBehaviour mergeBehaviour = keepChanges ? FaultChangeBehaviourReapply : FaultChangeBehaviourIgnore; [self faultObjectGraphForObject:managedObject handledObjects:handledObjects mergeChanges:mergeBehaviour]; } + (void)refreshObject:(NSManagedObject *)managedObject { [self faultObjectImpl:managedObject mergeChanges:FaultChangeBehaviourMerge]; } + (void)refreshObjectGraphForObject:(NSManagedObject *)managedObject { NSMutableArray *handledObjects = [NSMutableArray arrayWithCapacity:64]; [self faultObjectGraphForObject:managedObject handledObjects:handledObjects mergeChanges:FaultChangeBehaviourMerge]; } @end @implementation CoreDataHelper(Private) + (void)faultObjectImpl:(NSManagedObject *)managedObject mergeChanges:(FaultChangeBehaviour)mergeChanges { //Only fault if the object is not a fault yet and is not in a modified state or newly inserted (not saved yet) BOOL isFault = [managedObject isFault]; BOOL isTemporary = [[managedObject objectID] isTemporaryID]; BOOL isUpdated = [managedObject isUpdated]; NSDictionary *changedValues = [managedObject changedValues]; if (isUpdated && (mergeChanges == FaultChangeBehaviourIgnore)) { NSLog(@"Warning, faulting object of class: %@ with changed values: %@. The changes will be lost!", NSStringFromClass([managedObject class]), changedValues); } if (!isFault && !isTemporary) { [[managedObject managedObjectContext] refreshObject:managedObject mergeChanges:(mergeChanges == FaultChangeBehaviourMerge)]; if (mergeChanges == FaultChangeBehaviourReapply) { for (NSString *key in changedValues) { id value = [changedValues objectForKey:key]; @try { [managedObject setValue:value forKey:key]; } @catch (id exception) { NSLog(@"Could not reapply changed value: %@ for key: %@ on managedObject of class: %@", value, key, NSStringFromClass([managedObject class])); } } } } } + (void)faultObjectGraphForObject:(NSManagedObject *)managedObject handledObjects:(NSMutableArray *)handledObjects mergeChanges:(FaultChangeBehaviour)mergeChanges { if (managedObject != nil && ![managedObject isFault] && ![handledObjects containsObject:[managedObject objectID]]) { [handledObjects addObject:[managedObject objectID]]; NSEntityDescription *entity = [managedObject entity]; NSDictionary *relationShips = [entity relationshipsByName]; NSArray *relationShipNames = [relationShips allKeys]; for (int i = 0; i < relationShipNames.count; ++i) { NSString *relationShipName = [relationShipNames objectAtIndex:i]; if (![managedObject hasFaultForRelationshipNamed:relationShipName]) { id relationShipTarget = [managedObject valueForKey:relationShipName]; NSRelationshipDescription *relationShipDescription = [relationShips objectForKey:relationShipName]; if ([relationShipDescription isToMany]) { NSSet *set = [NSSet setWithSet:relationShipTarget]; for (NSManagedObject* object in set) { [self faultObjectGraphForObject:object handledObjects:handledObjects mergeChanges:mergeChanges]; } } else { NSManagedObject *object = relationShipTarget; [self faultObjectGraphForObject:object handledObjects:handledObjects mergeChanges:mergeChanges]; } } } [self faultObjectImpl:managedObject mergeChanges:mergeChanges]; } } @end </code></pre>

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