objective-c : Core Data Properties and Instance Methods

Core Data Properties and Instance Methods.m

//Core Data Properties and Instance Methods

//AppDelegate.m

#pragma mark - Properties

- (NSManagedObjectContext *)managedObjectContext
{
    if (_managedObjectContext != nil)
    {
        return _managedObjectContext;
    }
    
    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    
    if (coordinator != nil)
    {
        _managedObjectContext = [[NSManagedObjectContext alloc] init];
        [_managedObjectContext setPersistentStoreCoordinator:coordinator];
    }
    
    return _managedObjectContext;
}



- (NSManagedObjectModel *)managedObjectModel
{
    if (_managedObjectModel != nil)
    {
        return _managedObjectModel;
    }
    
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"ControllingSource" withExtension:@"momd"];
    _managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    
    return _managedObjectModel;
}



- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (_persistentStoreCoordinator != nil)
    {
        return _persistentStoreCoordinator;
    }
    
    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"ControllingSource.sqlite"];
    
    NSError *error = nil;
    _persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
    
    if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error])
    {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }    
    
    return _persistentStoreCoordinator;
}



#pragma mark - Instance Methods

- (NSURL *)applicationDocumentsDirectory
{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}



- (void)saveContext
{
    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
 
    if (managedObjectContext != nil)
    {
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error])
        {
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        }
    }
}