kotlin-stdlib/kotlin.jvm.optionals/toCollection

toCollection

fun <T : Any, C : MutableCollection<in T>> Optional<T>.toCollection(destination: C): C(source)

Appends this Optional's value to the given destination collection if present.

Since Kotlin

1.8

Samples

import java.util.Optional
import kotlin.jvm.optionals.*

fun main() { 
   //sampleStart 
   val maybeItsAnAnimal = Optional.of("Anonymous Capybara")
val maybeItsAnAnimalAsWell = Optional.empty<String>()
val animals = arrayListOf("Hilarious Honey Badger")
// Add to the collection if present
maybeItsAnAnimal.toCollection(animals)
maybeItsAnAnimalAsWell.toCollection(animals)

println(animals) // [Hilarious Honey Badger, Anonymous Capybara] 
   //sampleEnd
}