Question

I need to sort I need to subclass NSDate to add a tag, I don’t need to change its behaviour, do I still need to implement my own:

• (NSTimeInterval)timeIntervalSinceReferenceDate

• (id)initWithTimeIntervalSinceReferenceDate:(NSTimeInterval)seconds;

as stated in apple’s documentation? If so, how do I do it?

currently I just created a class extends NSDate with a tag attribute, but how do I initialise it?

Thanks!

Answer 1

NSDate is a class cluster, not a simple class. It is not wise to subclass a class cluster unless you know exactly what you are doing; see How do I subclass NSDate?

I would recommend that you create your own class containing an NSDate and a tag, and extend as needed:

@interface MyClass : NSObject {
  NSDate *_date;
  NSUInteger _tag;
}
@end

Add the appropriate properties, etc for easy dot-notation access.