NSManagedObject Custom Accessor Method

I hope someone can give me some helpful suggestions on what to do about this.

I have been trying several ways to sort a set of entities that have the relationship client<-->>job based on a custom accessor for a property of client as the first sort descriptor, and then the job description property as the second sort descriptor.

I first tried to use a transient property, called Client.sortValue, and discovered that transient properties can't be used as sort descriptors with the NSFetchedResultsController. So I changed the property Client.sortValue to be non-transient.

I never save a value for sortValue to the persistent store. Instead, I use a custom accessor. Apparently, the custom accessor method is not being used when the fetechedResultsController performFetch: method is run. It is called when I do logging, as shown in the code below. I can see that this is the case using a break point in the custom accessor and viewing the stack trace. I don't see it break on the accessor method when the performFetch is run, but it does break on the accessor method when the logging is done.

(Strangely, I had it working earlier today under some circumstances, but not others. It was obviously being sorted the way I wanted it to be, but after I refactored my code to track down the conditions where it worked, I have not seen it work again.)

I have tried various custom accessor methods, including the following:

- (NSString *) primitiveSortValue {

    NSString *retVal = nil;

    [self willAccessValueForKey:@"lastName"];
    [self willAccessValueForKey:@"firstName"];
    [self willAccessValueForKey:@"company"];

    if (![self.lastName isNullString] ) retVal = [self primitiveValueForKey:@"lastName"]; 
    else if (![self.firstName isNullString] ) retVal = [self primitiveValueForKey:@"firstName"]; 
    else if (![self.company isNullString] ) retVal = [self primitiveValueForKey:@"company"]; 
    else retVal = @"";

    [self didAccessValueForKey:@"lastName"];
    [self didAccessValueForKey:@"firstName"];
    [self didAccessValueForKey:@"company"];


    NSLog(@"Sort Value: %@", retVal);

    return retVal;
}  

I also tried this one before deciding to override the primitive accessor method:

- (NSString *) sortValue {

    NSString *retVal = nil;

    if (![self.lastName isNullString] ) retVal = self.lastName; 
    else if (![self.firstName isNullString] ) retVal = self.firstName; 
    else if (![self.company isNullString] ) retVal = self.company; 
    else retVal = @"";


    NSLog(@"Sort Value: %@", retVal);

    return retVal;
} 

Here is my fetchedResultsController method:

#define CLIENT_SORT_KEY @"clientOfJob.sortValue"
- (NSFetchedResultsController *) fetchedResultsController {
    if (fetchedResultsController != nil) {
        return fetchedResultsController;
    }

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription * entity = [NSEntityDescription entityForName:@"Job" inManagedObjectContext:dataInterface.managedObjectContext];

    [fetchRequest setEntity:entity];

    [fetchRequest setFetchBatchSize:10];

    if (segmentedControl.selectedSegmentIndex == 0) {  // sort by client, then job dscription
        NSSortDescriptor *clientSortDescriptor = [[NSSortDescriptor alloc] initWithKey:CLIENT_SORT_KEY ascending:YES];
        NSSortDescriptor *jobSortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"jobDescription" ascending:YES];

        NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:clientSortDescriptor, jobSortDescriptor, nil];
        [fetchRequest setSortDescriptors:sortDescriptors];

        NSFetchedResultsController *aFetchedResultsController = 
        [[NSFetchedResultsController alloc] 
         initWithFetchRequest:fetchRequest 
         managedObjectContext:dataInterface.managedObjectContext 
         sectionNameKeyPath:CLIENT_SORT_KEY
         cacheName:nil]; 


        aFetchedResultsController.delegate = self;

        self.fetchedResultsController = aFetchedResultsController;

        [aFetchedResultsController release];
        [fetchRequest release];
        [jobSortDescriptor release];
        [clientSortDescriptor release];
        [sortDescriptors release];        
    }
    else { // sort by job description
        ...        }

    NSError *error = nil;

    if (![fetchedResultsController performFetch:&error]) {
        NSLog(@"Unresolved Error %@, %@", error, [error userInfo]);
        abort();
    } 

    int i = 0;
    for (id<NSFetchedResultsSectionInfo> sectionItem in [fetchedResultsController sections]){
        NSLog(@"\n***********\nsection %d name %@\n-----------\n",i++, [sectionItem name]);
        int j = 0;
        for (Job *jobItem in [sectionItem objects]) {
            NSLog(@"%d job: %@, client: %@\n",j, jobItem.jobDes开发者_JS百科cription, jobItem.clientOfJob.sortValue);
        }
    }

    return fetchedResultsController;

}