Merge two objects of same type

Question

I have two objects:

deviceConfigInfo and deviceStatusInfo

Both contain an array of devices (so theres a third device object actually).

For each device returned in deviceConfigInfo there are these properties:

• uuid
• name
• somethingElse
• lookAnotherOne

and for deviceStatusInfo

• uuid
• name
• somethingElse
• someStatusInfo
• someMoreStuff

(If you hadn't guessed, I just made up some random properties)

So back to that third object I mentioned, device, I created it with all the properties combined. Now, my question is, say the deviceStatusInfo gets updated, how can I update the device object without losing the "old" data that isn't overwritten (in this case, the lookAnotherOne property).

Does it have to be a manual process of getting the device with the matching uuid and then updating each of the properties for deviceStatusInfo or is there a quicker way of doing this? Imagine there were loads of properties.

Hopefully this makes sense. If it helps, I am using Mantle to create the objects/models.

Answer 1

I noticed that Mantle has the following function which I was able to use:

mergeValueForKey:fromModel:

So in my device model, I added two functions:

• mergeConfigInfoKeysFromModel:
• mergeStatusInfoKeysFromModel:

These functions have access to an array that contains NSString values representing the properties/keys. There is one array for the configInfo and another for statusInfo properties/keys.

I then loop through the keys and use valueForKey to check it has an actual value. If it does, I then call the mergeValueForKey:fromModel:.

Example Code:

- (void)mergeConfigInfoKeysFromModel:(MTLModel *)model
{
    NSArray *configInfoKeys = @[@"uuid", @"name", @"somethingElse", @"lookAnotherOne"];

    for (NSString *key in configInfoKeys) {
        if ([model valueForKey:key]) {
            [self mergeValueForKey:key fromModel:model];
        }
    }
}

All I have to do now, is call the appropriate merge function on the device object when I get an update, passing over the updated device object. Just as below:

[self.device mergeConfigInfoKeysFromModel:deviceUpdate];