Access delegate object from a method - kotlin

Question

Consider the following Kotlin code:
class Derived(n1: String, n2:String) : Teacher by TeacherImp(),Person by PersonImpl(n1, n2) {
// desire to call method of PersonImp object... possible??
}
Is there any way to access the delegate object instances?
Consider if the derived class wants to access a method of a delegate.

Answer 1

You can save the delegate(s) into private immutable property(s) - for example:
interface Teacher {
fun sayHelloTeacher() = println("Teacher hello")
}
interface Person {
fun sayHelloPerson() = println("Person hello")
}
class TeacherImp : Teacher {
fun sayHelloTeacherImp() = println("TeacherImp hello")
}
class PersonImp(val n1: String, val n2: String) : Person {
fun sayHelloPersonImp() = println("PersonImp hello $n1 $n2")
}
class Derived private constructor(private val t: TeacherImp, private val p: PersonImp) :
Teacher by t, Person by p {
constructor(n1: String, n2: String) : this(TeacherImp(), PersonImp(n1, n2))
init {
sayHelloPerson()
sayHelloTeacher()
t.sayHelloTeacherImp()
p.sayHelloPersonImp()
}
}
fun main(args: Array<String>) {
Derived("first", "second")
}
With this implementation the only public constructor is the same as the original, and which calls the private constructor that stores the actual objects.
Note: With reflection it may possible to access them without the extra constructor, but I think this is a straightforward solution to your problem.