Wsrtjtyk

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?

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;

}