Question

I am using CoreData in an iOS application. Everything works fine except for fields marked as Boolean in xcdatamodel that get modeled and NSNumber.
For this kind of fields I want to write some utility method in extended class, but I was wondering where’s the best location for writing them or what’s the best practice.

In MyManagedObject.h I have:

@interface MyManagedObject : NSManagedObject {
@private
}
@property (nonatomic, retain) NSNumber * mandatory;
@end

Where mandatory is a boolean in data model. This is the generated class from xcode:

@implementation MyManagedObject
@dynamic mandatory;

At this point, for properly using the entity I need to write somewhere some utility wrapper methods, probably in the entity itself, such as:

[myManagedObject mandatoryWrapper:YES];


-(void)mandatoryWrapper:(BOOL)mandatory {
    // convert boolean to number
    self.mandatory=convertedMandatory;
}

But I am aiming to use the original getter/setter for not generating “confusion”:

// setter
myManagedObject.mandatory=YES;
//getter
if(myManagedObject.isMandatory)

but I suppose that rewriting the original methods, will cause some problem later on in the application lifecycle, for example when saving or retrieving in context.

thanks.

Answer 1

If you want a true boolean property, then your are forced to change the name. I would recommend just making the it a property of the class and not the entity because the entity doesn’t have to know about them.

In your case, you would need something like:

@property BOOL isMandatory;

-(BOOL) isMandatory{
   return [self.mandatory boolValue];
}

-(void) setIsMandatory:(BOOL) boolVal{
  self.mandatory=[NSNumber numberWithBool:boolVal];
}

This lets you use convience constructions like:

If (self.isMandtaory)...
self.isMandatory=YES;

Core Data is happy because the entity modeled NSNumber property is still there and works as expected but the human can use the easier to comprehend boolean version.