CODEWITHSUNDEEP
iosswiftfinal
SergStav
SergStav

Reputation: 757

Swift. Make all classes final?

My question is about using final keyword im Swift code. I know that final helps compiler to compile code faster because of dynamic dispatch. So, if I definitely know that I will not inherit some of my classes, should I make all of them final?

Upvotes: 5

Views: 2622

Answers (3)

Blazej SLEBODA
Blazej SLEBODA

Reputation: 9925

If your app or a framework uses a protocols over inheritance then you can define your class types as finals.

If you prefer to use an inheritance over protocols and your app or framework is tested with a Unit Tests then don't define your class types as finals when they are used for a dependency objects because they will not be able to be mocked.

Upvotes: 0

mfaani
mfaani

Reputation: 36297

There was this protective approach taught by the iOS Stanford course.

The approach was, define all your APIs private. It increases encapsulation. Later if you needed to give away something then remove the privacy.

Because it's bad to do it the other way around ie design something public and then later change it to private.

Similarly here, I think making a class final and then later deciding it shouldn't be final is better than making a class non-final, allowing multiple classes to subclass it and then later attempt to revert it back to final because of some design decisions.

Upvotes: 9

Casey West
Casey West

Reputation: 576

You are fine to do so if you are 110% you won't attempt to subclass any of your 'final' classes, as your project won't compile if you do so.

The article below has some great information and should help you decide.

http://blog.human-friendly.com/the-importance-of-being-final

Upvotes: 2

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