The basic pattern to do this is to store a 'raw' value of type NSNumber in the Core Data model and extend your generated NSManagedObject class to add an additional property.
For example if your generated class file is:
import Foundation
import CoreData
@objc(MyEntity)
class MyEntity: NSManagedObject {
@NSManaged var myPropertyRaw: NSNumber
You can create a separate Swift file to extend this generated class with an additional property that provides the conversion to your enumeration:
import Foundation
enum MyEnumeration:Int {
case Value0 = 0
case Value1 = 1
case Value2 = 2
}
extension MyEntity {
var myProperty: MyEnumeration {
get {
return MyEnumeration(rawValue: myPropertyRaw.integerValue)!
}
set {
myPropertyRaw = NSNumber(integer: newValue.rawValue)
}
}
}
For this to work your enumeration must have an integer rawType. In the example this is just Int. Alternatively you could define it to use an integer type with a specific size - Int8, Int16, Int32 or Int64.
If you do use one of these types you will have to amend your property definition to use the right parameters:
// Int8
get {
return MyEnumeration(rawValue: dateTypeRaw.charValue)!
}
set {
myPropertyRaw = NSNumber(char: newValue.rawValue)
}
// Int16
get {
return MyEnumeration(rawValue: dateTypeRaw.shortValue)!
}
set {
myPropertyRaw = NSNumber(short: newValue.rawValue)
}
// Int32
get {
return MyEnumeration(rawValue: dateTypeRaw.intValue)!
}
set {
myPropertyRaw = NSNumber(int: newValue.rawValue)
}
// Int64
get {
return MyEnumeration(rawValue: dateTypeRaw.longLongValue)!
}
set {
myPropertyRaw = NSNumber(longLong: newValue.rawValue)
}
You have to put the extension in a separate file because you will have to regenerate the MyEntity.Swift file anytime you make changes to your MyEntity definition in your data model.
BTW you currently have to add the @objc(MyEntity) line to the generated file manually to enable Swift to work with the generated class.
