CODEWITHSUNDEEP
kotlininheritance
kirill.login
kirill.login

Reputation: 961

How do I pass superclass properties in subclass constructor in Kotlin

I'm new to Kotlin. And I'm struggling with inheritance. Consider the following case.

This code is ok

open class BaseClass(
   val property1: String,
   val property2: String,
)

And this one also

data class ExtendedClass(
   val propety3: String
): BaseClass()

But here we have a compilation problem

val extended = ExtendedClass(
   property1 = "", 
   property2 = "", 
   property3 = ""
)

What is the use of open class inheritance if it's prohibited to construct sub-classes in that way? Instead I have to do something like

val extended = ExtendedClass(property3 = "")
extended.property1 = "",
extended.property2 = ""

But that trick kills immutability.

Upvotes: 2

Views: 1419

Answers (1)

lpizzinidev
lpizzinidev

Reputation: 13284

You may want to declare the BaseClass as abstract and inherith its properties in the ExtendedClass:

abstract class BaseClass {
   abstract val property1: String
   abstract val property2: String
}

class ExtendedClass(
    override val property1: String,
    override val property2: String,
    val propety3: String
) : BaseClass()

You can then initialize the ExtendedClass with the 3 immutable properties:

val extendedClass = ExtendedClass(
    property1 = "Property 1", 
    property2 = "Property 2", 
    property3 = "Property 3"
)

Upvotes: 1

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