Question

I’d like to play around with attribute value validation, but the documentation is pretty empty on this. Maybe there’s an good article or tutorial out there?

Answer 1

Here is a fairly common validation to ensure you don’t get nonsensical dates put into a timeStamp.

- (BOOL)validateTimeStamp:(id *)valueRef error:(NSError **)outError 
{
    NSDate *testDate=(NSDate *) valueRef;
    if ([testDate compare:self.minimumTimeStamp]==NSOrderedAscending) {
        // generate and return error so you can set a proper date
    }
    return YES;
}