None

The case of Optional holding no value. Always the same, shared singleton instance.

Properties

Whether this Optional holds no value, i.e. whether it is None. Always !isPresent.

open override val isPresent: Boolean

Whether this Optional holds a value, i.e. whether it is a Some.

open override val value: Nothing?

The contained value, or null if this is None.

open override fun filter(predicate: (Nothing) -> Boolean): Optional.None

Returns None, without invoking predicate (there is no value to test).

open override fun <R> map(function: (Nothing) -> R): Optional.None

Returns None, without invoking function (there is no value to apply it to).

Returns an empty Sequence.

open override fun toString(): String