I have a class where I want to be able to modify a list internally, but externally I want the list to be immutable; for example...
class Foo {
val items: List<String> get() = mutableItems
private val mutableItems: MutableList<String> = mutableListOf()
}
Is there a nicer way to express this?
No, but they have something in the works that might appear in a future version of Kotlin. The suggested syntax would look something like this:
private val items: MutableList<String> = mutableListOf()
public get(): List<String>
This was presented by the language design lead in a talk about possible future features of Kotlin.
To be a bit pedantic, you are exposing a read-only List, not an immutable one.
You can do something like this:
private val items : MutableList<String> = mutableListOf()
fun items() : List<String> = items
When you want to access your items externally just use items() function. In internal usage work with list directly