Is it possible to encapsulate open and override variables to prevent direct access from main() function while implementing inheritance in Kotlin?

Question

My code -

fun main() {
    val student = Student()
    student.greet()
}

open class Person(open var name: String) {
    fun greet() {
        println("Hello $name")
    }
}

class Student(override var name: String = "John Doe"): Person(name) {

}

Here I have a parent class Person and a child class Student. parent class Person has property name and method greet(). child class Student is inheriting them.

Here I am able to directly modify name variable of Student class from main() function using student.name. I want to encapsulate name variable to prevent name from being directly modified from main() function so that the constructor Student() is the only way to set the value of name variable.

Usually private visibility modifier keyword is used to encapsulate variables in a class. But apparently when the variables have open or override modifier, this technique does not work.

So, is it possible to encapsulate name variable?

Answer 1

Remove the open keyword, and call the Person's constructor to set it instead of overriding it from Student (which is also null-prone at the init block of Person, see here):

open class Person(private var _name: String) {
    val name get() = _name

    fun greet() {
        println("Hello $name")
    }
}

class Student(name: String = "John Doe"): Person(name) {

}