Box

data class Box<T : Any>(val generator: () -> T, var value: T? = null)(source)

A lazily-instantiated reference to an object of type T.

Parameters

the type of the referenced object

generator

generates the referenced object when unaryPlus is invoked for the first time

value

do not assign this field in the constructor; this field is placed in the constructor to ensure Kotlin includes it in the automatically-generated copy method

Constructors

Box

constructor(generator: () -> T, value: T? = null)

Properties

generator

private val generator: () -> T

value

private var value: T?

Functions

unaryPlus

operator fun unaryPlus(): T

If this method is invoked for the first time, generator is invoked and the result is returned. In subsequent invocations of this method, the previously-generated value is returned each time.