NSManagedObject with Rails-ish timestamps

NSManagedObjectWithTimestamps.h

//
//  NSManagedObjectWithTimestamps.h
//  Brainbow Apps, 2011
//

#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>

@interface NSManagedObjectWithTimestamps : NSManagedObject

@property (assign) NSDate *createdAt;
@property (assign) NSDate *updatedAt;

@end

NSManagedObjectWithTimestamps.m

//
//  NSManagedObjectWithTimestamps.m
//  Brainbow Apps, 2011
//

#import "NSManagedObjectWithTimestamps.h"


@interface NSManagedObjectWithTimestamps (Private)
-(void)touchTimestamps;
@end

@implementation NSManagedObjectWithTimestamps

@dynamic updatedAt, createdAt;

- (void)awakeFromInsert {
  [super awakeFromInsert];
  [self touchTimestamps];
}

- (void)awakeFromFetch {
  [super awakeFromFetch];
  [self touchTimestamps];
}

-(void)touchTimestamps {
  [self setPrimitiveValue:[NSDate date] forKey:@"updatedAt"];
  if (![self primitiveValueForKey:@"createdAt"]) {
    [self setPrimitiveValue:[NSDate date] forKey:@"createdAt"];
  }
}

@end