Re: Custom alerts for Core Data validation errors ... how to?

FROM : Richard Wolf
DATE : Fri Nov 30 21:30:26 2007

On Nov 30, 2007, at 4:24 AM, mmalc crawford wrote:

>
> On Nov 30, 2007, at 2:33 AM, Richard Wolf wrote:
>

>> "Normally" I'd be able to provide my own validation methods and 
>> craft the NSErrors ... but this is Core Data ... and the object 
>> model is doing the validation for me.
>>

> Why not just implement your own managed object validation methods?


Well, I've thought about that, I really have.  Problem is this:

In the data modeling tool in XCode, I have my entity defined nice and 
neat ... and the settings for my "sharedSecret" attribute are all 
laid out ... including the "Reg. Ex." text string ...

[A-Z0-9]{32,32}

I aspire to be a good, lazy programmer ... let the data modeling tool 
hang onto the regex if I can get away with it.  But if I do that, the 
only control I have over the error alert (short of doing a view/
window/doc delegate) is how the attribute name appears ... I can go 
from "sharedSecret" to "Shared secret".

Now I'm more than happy to move that regex string into a

-(BOOL)validateSharedSecret:(id *)ioValue error:(NSError **)outError

method in my NSManagedObject subclass.  But what I can't find is a 
way to do this:

BOOL result = [*ioValue matchesRegularExpression:@"[A-Z0-9]{32,32}"];

At least, so far as I know, there is no Apple-approved way to do 
that.  I could glom onto another Cocoa regex class, but I thought 
that ... somehow ... CoreData already knows how to do that ... so 
I'll do the work if I have to, but if there is some way to do it 
simply, I'd super-appreciative ("buy you a beer" appreciative) to 
know how.

Thanks Malcolm!