Final classes
Although class inheritance is very useful – and in fact large parts of Apple’s platforms require you to use it – sometimes you want to disallow other developers from building their own class based on yours.
Swift gives us a final keyword just for this purpose: when you declare a class as being final, no other class can inherit from it. This means they can’t override your methods in order to change your behavior – they need to use your class the way it was written.
To make a class final just put the final keyword before it, like this:
final class Dog {
var name: String
var breed: String
init(name: String, breed: String) {
self.name = name
self.breed = breed
}
}
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