Separating classes - class

Question

I have a class called UFDevice, in order to initialise it needs a location string.
I also have a class called UFResponse which among other things provides a location.
As the device only requires a location should I just take that in, so that it could be init'ed in some use case where there is no UFResponse.
Or should I pass in the whole response, in case later on it needs more info than just the location?
in pseudocode:
foundDevice(Data data) {
response = new UFResponse(data);
device = new UFDevice(response);
}
or:
foundDevice(Data data) {
response = new UFResponse(data);
device = new UFDevice(response.location);
}
or even should I encapsulate UFResponse in UFDevice, as currently it's only used to create UFDevices:
foundDevice(Data data) {
device = new UFDevice(data);
}
Future possibilities could include:
//maybe in the future I have saved a favourite location so need to do:
loadFavourite(String location) {
device = new UFDevice(location);
}
//or device needs more info
device = new UFDevice(location, color, ...20 more parameters...);
Where do I draw the line of separation? More importantly how can I decide this for myself in the future?

Answer 1

It sounds like a problem of interface segragation (https://en.wikipedia.org/wiki/Interface_segregation_principle). UFDevice is constructed from a UFResponse, but it doesn't need everything the UFResponse contains. It only needs a part of it, and you don't want UFDevice to be affected when UFResponse is changing in areas that should not affect UFDevice.
One approach is to have UFResponse inherit from an interface called UFDeviceParams, if this makes sense (might be multiple inheritance), and then UFDevice should get in its constructor a reference to UFDeviceParams.
This allows to initialize UFDevice based on the entire UFResponse, or based on a more light-weight instance of UFFavouriteParams (that also inherits from UFDeviceParams) that contains only the location + color etc...
foundDevice(Data data) {
response = new UFResponse(data);
device = new UFDevice(response);
}
loadFavourite(String location) {
params = new UFFavouriteParams(location);
device = new UFDevice(params);
}
To really know if this is the best approach for your case, one would need to learn more about your system, understand the use cases and the boundaries between modules. I recommend to watch Robert Martin's video on the Interface Segratation Principle and SOLID principles in general (https://cleancoders.com/category/solid-principles)