CODEWITHSUNDEEP
genericskotlin
user7559705
user7559705

Reputation:

Generics with inner classes in kotlin

I have a sealed class which contain some data classes as shown below. Is there a way to know which class (D1, D2, D3) I am working with in T1.printclassname()?

sealed class A {
  data class D1 { }
  data class D2 { }
  data class D3 { }
}
class T1 {
    fun <E : A> printclassname(val c: E) {

    }
}

And trying the same with inner classes 

internal class B {
  inner class X1 { }
  inner class X2 { }
  inner class X3 { }
}
class T2 {
    fun <E : B> printclassname(val c: E) {
      if (c is B.X1){
         // some op.
        }
    }
}

The printclassname() shoudl accept any object of D1, D2, D3. and printclassname1 should accept any object of X1, X2, X3

Upvotes: 1

Views: 1706

Answers (1)

Sergio
Sergio

Reputation: 30665

You should inherit classes A and B respectively:

fun main(args: Array<String>) {
    printClassName1(A.D1("some value"))
    printClassName(B().X1())
}

sealed class A {
    // Data classes must have at least one primary constructor parameter
    data class D1(val p: String): A() { }
    data class D2(val p: String): A() { }
    data class D3(val p: String): A() { }
}

// make this class open to be able to inherit
open class B {
    inner class X1: B() { }
    inner class X2: B() { }
    inner class X3: B() { }
}
fun <E : B> printClassName(c: E) {
    println("name=${c::class.simpleName}")
}

fun <E : A> printClassName1(c: E) {
    println("name=${c::class.simpleName}")
}

The output:

name=D1
name=X1

Upvotes: 1

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