Recently I have worked with Core Data. When I want to set a default value for some fields, I came up with this problem:

So I made a simple represent:

We have 2 class Parent and Child, in which Child inherit from Parent.

// Parent.h
@interface Parent : NSObject
@property (strong, nonatomic) NSString *lastName;



// Child.h
@interface Child : Parent

In Parent class, I made a custom getter to set a default value when nothing is set:

// Parent.h
- (NSString *)lastName
{
    if (_lastName) {
        return _lastName;
    } else {
        return @"Parent Default Name";
    }
}

But I cannot make a custom default value for the field "name" which Child inherits from its Parent.

// Child.h
@implementation Child

- (NSString *)lastname
{
    if (super.lastName) {
        return super.lastName;
    } else {
        return @"Child Default Name";
    }
}

Apparently, this method is never called. So my question here is: How can I set a custom getter for the field the Child class inherits from Parent without define an overriding property?