Add a custom accessor to property without renaming constructor parameter in Scala

Question

For example, I have the following class

class Person(val name: String) { }

Some code use this class invoking constructor with named parameters

val person = new Person(name = "Smith")
println(person.name)

I need to add a custom accessor for property name without braking code like above. So approach with renaming a constructor parameter does not suite me

class Person(val _name: String) {
  def name = {
    println("custom action")
    _name
  }
}

Is there any other way? If no, does it mean that for new classes I always should manually make custom accessors to ensure encapsulation?

Answer 1

You can make your primary constructor private and add some extra value to it to prevent ambiguity.

class Person private (_name: String, dummy: Unit) {
  def this(name: String) = this(name, ())
  def name: String = {
    println("custom action")
    _name
  }
}

new Person(name = "John").name // will print "custom action"

It's hacky, but I'll prefer that over Java maybe-I'll-need-it-later style accessors