KTypeProjection

data class KTypeProjection (source)

Platform and version requirements: Kotlin 1.1

Represents a type projection. Type projection is usually the argument to another type in a type usage. For example, in the type Array<out Number>, out Number is the covariant projection of the type represented by the class Number.

Type projection is either the star projection, or an entity consisting of a specific type plus optional variance.

See the Kotlin language documentation for more information.

Constructors

<init>

KTypeProjection(variance: KVariance?, type: KType?)

Represents a type projection. Type projection is usually the argument to another type in a type usage. For example, in the type Array<out Number>, out Number is the covariant projection of the type represented by the class Number.

Properties

type

val type: KType?

The type specified in the projection, or null if this is a star projection.

variance

val variance: KVariance?

The use-site variance specified in the projection, or null if this is a star projection.

Companion Object Properties

STAR

val STAR: KTypeProjection

Star projection, denoted by the * character. For example, in the type KClass<*>, * is the star projection. See the Kotlin language documentation for more information.

Companion Object Functions

contravariant

fun contravariant(type: KType): KTypeProjection

Creates a contravariant projection of a given type, denoted by the in modifier applied to a type. For example, in the type MutableList<in Number>, in Number is a contravariant projection of the type of class Number.

covariant

fun covariant(type: KType): KTypeProjection

Creates a covariant projection of a given type, denoted by the out modifier applied to a type. For example, in the type Array<out Number>, out Number is a covariant projection of the type of class Number.

invariant

fun invariant(type: KType): KTypeProjection

Creates an invariant projection of a given type. Invariant projection is just the type itself, without any use-site variance modifiers applied to it. For example, in the type Set<String>, String is an invariant projection of the type represented by the class String.