Xcode: New NSManagedObject subclass generator

Xcode 7 includes new generator of NSManagedObject subclasses and it works for both Swift and Objective-C classes.

I was playing with Core Data and I noticed that Xcode 7 generates subclasses for entities in a different manner and this is cool. It does similar work like mogenerator but instead of creating “human” and “machine” classes like mogenerator does it creates class for entity where class logic is and CoreDataProperties extension which contains declaration of attributes of the entity.


class Quote: NSManagedObject {
    // Logic goes here


import Foundation
import CoreData

extension Quote {

    @NSManaged var author: String?
    @NSManaged var content: String?
    @NSManaged var objectId: String?
    @NSManaged var readCount: NSNumber?



I like that extension is generated and properties are there, it ensure that regenerating subclass will not overwrite class logic - Finally!


The generator or better Core Data model editor should have more “advanced” options - I meant, hey, there is no option to select if property is optional or not. It generates properties and marks them optionals by default - I don’t like it because in my case I want non-optional properties for Quote class - rdar://21785457 opened.

It should be generated as below:

import Foundation
import CoreData

extension Quote {

    @NSManaged var author: String
    @NSManaged var content: String
    @NSManaged var objectId: String
    @NSManaged var readCount: NSNumber


What I am sad about is also that even readCount has specified default value set to 0 it also generate it as optional.

The second thing I noticed is that regenerating class after e.g. model has been updated causes that Xcode asks whether you want to replace existing extension of entity class file with new properties declarations. If you confirm it will replace extension which is okay, but it also adds extra reference to this extension to the project navigator there are two references pointing to the same file - rdar://21785404 opened.


This is nice that we’ve got finally generator that separates properties declaration from entity logic. I think this new generator is a good tool for first time generation of newly added entity. Looking for my sad things I recommend to update the extension manually every time when it changes and when you’ve got custom code inside extension file like: non-default access modifiers or properties marked non-optionals.