Retrieving values from a large dictionary at runtime in a MacOS app - objective-c

Question

I come from a mostly ruby/js background. Our MacOS app hasn't been updated in a few years and there's no one on the team right now that does ObjC full time. I've always been curious, so I'm taking a crack at a ticket for a tiny feature in our MacOS app.
Here's what it boils down to:
We have a view with 5 columns, one of which displays an item's ID. We want to start displaying the facility name associated with that ID, which we currently have in a giant (~16k lines) json file.
Here's how the columns are initialized when we configure the UI:
NSTableColumn * checkedColumn = [[NSTableColumn alloc] initWithIdentifier:#"active"];
[[checkedColumn headerCell] setStringValue:#"Active"];
[checkedColumn setWidth:30];
[checkedColumn setEditable:YES];
[inventoryTable addTableColumn:checkedColumn];
NSTableColumn * idColumn = [[NSTableColumn alloc] initWithIdentifier:#"id"];
[[idColumn headerCell] setStringValue:#"ID"];
[idColumn setWidth:120];
[idColumn setEditable:NO];
[inventoryTable addTableColumn:idColumn];
NSTableColumn * ownerColumn = [[NSTableColumn alloc] initWithIdentifier:#"owner"];
[[ownerColumn headerCell] setStringValue:#"Owner"];
[ownerColumn setWidth:120];
[ownerColumn setEditable:NO];
[inventoryTable addTableColumn:ownerColumn];
NSTableColumn * countColumn = [[NSTableColumn alloc] initWithIdentifier:#"count"];
[[countColumn headerCell] setStringValue:#"Count"];
[countColumn setWidth:120];
[countColumn setEditable:NO];
[inventoryTable addTableColumn:countColumn];
NSTableColumn * pendingColumn = [[NSTableColumn alloc] initWithIdentifier:#"pending"];
[[pendingColumn headerCell] setStringValue:#"Pending"];
[pendingColumn setWidth:70];
[pendingColumn setEditable:NO];
[inventoryTable addTableColumn:pendingColumn];
I added the following to create the new column:
NSTableColumn * facilityColumn = [[NSTableColumn alloc] initWithIdentifier:#"facility"];
[[facilityColumn headerCell] setStringValue:#"Facility"];
[facilityColumn setWidth:120];
[facilityColumn setEditable:NO];
[inventoryTable addTableColumn:facilityColumn];
The original rendering in the tableView was this:
- (id)tableView:(NSTableView *)tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row {
IVClient * client = [allClients objectAtIndex:row];
if ([[tableColumn identifier] isEqualToString:#"id"]) {
return PropToString(client.id);
} else if ([[tableColumn identifier] isEqualToString:#"owner"]) {
return PropToString(client.owner);
} else if ([[tableColumn identifier] isEqualToString:#"count"]) {
return [NSNumber numberWithInt:client.count];
} else if ([[tableColumn identifier] isEqualToString:#"pending"]) {
return [NSNumber numberWithBool:client.pending];
} else if ([[tableColumn identifier] isEqualToString:#"active"]) {
return [NSNumber numberWithBool:client.active];
}
return nil;
}
and i added a condition to match the new value:
else if ([[tableColumn identifier] isEqualToString:#"facility"]){
return FacilityNameFromID(client.id);
}
I have only a surface level grasp of how to interact with Obj C data structures, but it seems like this should be pretty straightforward and i have to either:
1) Store the chunk of data in a dictionary and check for an ID match every time we render rows
or
2) Store it in a db and query by ID.
It seems like holding that much data in a dictionary is excessive but I'm going into this pretty blind. If I were in my comfort zone and building a backend for an api with these same specs, I'd definitely go the db route. I'm just not familiar with CoreData whatsoever.
Would #1 at least be realistic for a smaller dataset?

Answer 1

16K lines, or even records, does not qualify as "giant" or even particularly large, in my eyes. A dictionary should be adequate. Certainly, it's where you should start before measuring and determining if the performance is a real problem. (Premature optimization and all that.)
After that, the first optimization I'd try would be to make a read-only property of IVClient called facilityName whose getter implementation does the lookup with caching. That is, something like:
- (NSString*) facilityName
{
if (!_facilityName)
_facilityName = FacilityNameFromID(self.id);
return _facilityName;
}