Added in API level 24

UnaryOperator

@FunctionalInterface interface UnaryOperator<T : Any!> : Function<T, T>

java.util.function.UnaryOperator

Represents an operation on a single operand that produces a result of the same type as its operand. This is a specialization of Function for the case where the operand and result are of the same type.

This is a functional interface whose functional method is apply(java.lang.Object).

Summary

Public methods
open static UnaryOperator<T>!	identity() Returns a unary operator that always returns its input argument.

Inherited functions

From class Function Function<T, V>! andThen(after: Function<in R, out V>!) Returns a composed function that first applies this function to its input, and then applies the after function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function. R apply(t: T) Applies this function to the given argument. Function<V, R>! compose(before: Function<in V, out T>!) Returns a composed function that first applies the before function to its input, and then applies this function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function.

Public methods

identity

Added in API level 24

open static fun <T : Any!> identity(): UnaryOperator<T>!

Returns a unary operator that always returns its input argument.

Parameters
<T>	the type of the input and output of the operator

Return
UnaryOperator<T>!	a unary operator that always returns its input argument