[Rubycocoa-talk] Core Data Question

[Rich W. <rw...@gm...>]

Hi,

I'm working on a RubyCocoa Core Data project. In that project, I'm  
trying to subclass NSManagedObject to return specific values for the  
count attribute. Count otherwise behaves like any other Core Data  
attribute.

The following Objective C code works fine. It correctly returns the  
number of posts associated with the posts relationship.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#import <Cocoa/Cocoa.h>


@interface ObjCManagedFeed : NSManagedObject {

}

-(int)count;

@end

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#import "ObjCManagedFeed.h"


@implementation ObjCManagedFeed

-(int)count {
	id posts = [self valueForKey:@"posts"];
	NSArray * all = [posts allObjects];
	return [all count];
}

@end

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


However, when I try to convert this to Ruby, the count() method is  
never called.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

require 'osx/cocoa'

class ManagedFeed < OSX::NSManagedObject
	def count()
		puts "*** This never gets called ***"
		posts = valueForKey_("posts")
		posts.allObjects.size
	end
end

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  I don't understand why; though it might be a bad interaction between  
Core Data's bindings and RubyCocoa's wrappers. I also wonder if this  
has anything to do with my last, KVO question. If anyone can explain  
this to me, I'd be grateful. Thanks.

-Rich-