Changing order of NSMutableOrderedSet CoreData relationship

Question

I am trying to replace objects in a many to one ordered CoreData relationship... My code is here:

NSMutableOrderedSet *battingLineUpTemp = [battingOrderToChange.battingOrder mutableCopy];
    NSUInteger newBatsmanIndex = 0;

NSLog(@"Original batting order");
for (CricketPlayer *p in battingLineUpTemp) {
    NSLog(@"switching : %@ %@",p.firstName, p.lastName);
}

for (int i = [innings.wicketsFallen integerValue] +2; i < [battingOrderToChange.battingOrder count]; i++) {

    //[battingLineUpTemp replaceObjectAtIndex:i withObject:batsmenArray[newBatsmanIndex]];
    [battingLineUpTemp replaceObjectAtIndex:i withObject:[batsmenArray objectAtIndex:newBatsmanIndex]];
    newBatsmanIndex++;

}

NSLog(@"Changed batting order");
for (CricketPlayer *p in battingLineUpTemp) {
    NSLog(@"switching : %@ %@",p.firstName, p.lastName);
}


[battingOrderToChange willChangeValueForKey:@"battingOrder"];
[battingOrderToChange setBattingOrder:[[NSOrderedSet alloc] initWithOrderedSet:[battingLineUpTemp copy]]];
battingOrderToChange.battingOrder = battingLineUpTemp;
[battingOrderToChange didChangeValueForKey:@"battingOrder"];

Yet the second time i output the players names I get the exact same result as beforehand! I have made sure that the NSArray (batsmenArray) which I'm passing to the method is not in the same order as *battingLineUpTemp... Why is my code refusing to let me change the order of this NSMutableOrderedSet!? Is it CoreData being a massive pain in the arse once again?

Edit 1 I have also made sure that the object that I am replacing and the one which it is replacing are different by NSLogging within the for loop... the NSMutableOrderedSet is simply refusing to be rearranged!

Answer 1

SimonThumper,

An ordered set has many uses, but it is primarily a mechanism to preserve insertion order. As you want to change your lineup order, I suggest you actually add a property to contain the position in the lineup and then sort on that order. (You could also use this as a property to easily pull the lineup out of the roster by checking for non-zero values in the lineup property.)

Andrew