CODEWITHSUNDEEP
swiftgenerics
Amrit Sidhu
Amrit Sidhu

Reputation: 1950

Passing generic parameters in a generic class

Is it possible to get something like below using generics in swift? Any help would be appreciated more than anything else. 

class ABC {
   var title: String?
}

class Option: <T> {
   var name: String?
   var data: T?
}

let object1 = ABC()

let option = Option(name: "Test", data: object1)

// Getting data again
let data = option.data

Upvotes: 0

Views: 51

Answers (1)

PGDev
PGDev

Reputation: 24341

Here is how you can use Generics in Swift.

protocol PPP {
    var title: String? {get set}
}

class ABC: PPP {
    var title: String?
}

class XYZ: PPP {
    var title: String?
}

class Option<T> {
    var name: String?
    var data: T?

    init(name: String?, data: T?) {
        self.name = name
        self.data = data
    }
}

let object1 = ABC()
let option1 = Option(name: "Test1", data: object1)

let object2 = XYZ()
let option2 = Option(name: "Test2", data: object2)

Since classes in Swift doesn't have a default initializer, so create one that accepts 2 parameters - String? and T?.

You can use type(of:) method to identify the type of an object.

print(type(of: option1.data)) //ABC
print(type(of: option2.data)) //XYZ

You can use protocol to access title in both ABC and XYZ.

Conform ABC and XYZ to protocol PPP and implement its title property in both ABC and XYZ.

print(option1.data?.title)
print(option2.data?.title)

Upvotes: 1

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