Swift Generics equivalent of Java any type <?>

Question

In Java you can some times use generics without caring about the actual type. Can you do that in Swift?

For instance MyClass<AnyObject> doesn't work like MyClass<?> would in Java. At I'd expect it to work the same.

Is there any other way?

Answer 1

Introduce a type parameter; the compiler will let it take any type. Try:

func executeRequest<T> (request: APIRequest<T>) {
 // ...
}

For example:

class APIRequest<T> {}
class Movie {}
class MovieRequest : APIRequest<Movie> {}
let m = MovieRequest()
//print(m)

func executeRequest<T> (request: APIRequest<T>) {
    print(request)
}

executeRequest(m)

The introduction of a type parameter allows one to be more explicit and to better match the problem domain. For example, in your case, you surely can't do a APIRequest on anything whatsoever; you can make an APIRequest on, say, a Resource.

protocol Resource {}
class Movie : Resource {}
class Song : Resource {}

class APIRequest<T:Resource> { /* ... */ }

func executeRequest<T:Resource> (request: APIRequest<T>) { /* ... */ }