Override getter for Kotlin data class

Question

Given the following Kotlin class:

data class Test(val value: Int)

How would I override the Int getter so that it returns 0 if

Answer 1

You could try something like this:

data class Test(private val _value: Int) {
  val value = _value
    get(): Int {
      return if (field < 0) 0 else field
    }
}

assert(1 == Test(1).value)
assert(0 == Test(0).value)
assert(0 == Test(-1).value)

assert(1 == Test(1)._value) // Fail because _value is private
assert(0 == Test(0)._value) // Fail because _value is private
assert(0 == Test(-1)._value) // Fail because _value is private

• In a data class you must to mark the primary constructor's parameters with either val or var.

• I'm assigning the value of _value to value in order to use the desired name for the property.

• I defined a custom accessor for the property with the logic you described.