How to check generic type in Kotlin?

Question

I have class

class Generic()

and this code is\'t correct

fun typeCheck(s: SuperType): Unit {
               


        

Answer 1

If you need to check if something is of generic type T you need to to have an instance of Class to check against. This is a common technique in Java however in Kotlin we can make use of an inlined factory method that gets us the class object.

class Generic(val klass: Class) {
    companion object {
        inline operator fun invoke() = Generic(T::class.java)
    }

    fun checkType(t: Any) {
        when {
            klass.isAssignableFrom(t.javaClass) -> println("Correct type")
            else -> println("Wrong type")
       }

    }
}

fun main(vararg args: String) {
    Generic().checkType("foo")
    Generic().checkType(1)
}