Package com.g2forge.alexandria.java.function.optional

Interface OptionalFunction<I,O>

All Superinterfaces:

Function<I,Optional<? extends O>>

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface OptionalFunction<I,O>
extends Function<I,Optional<? extends O>>

Method Summary

Modifier and Type	Method	Description
static <I,O> OptionalFunction<I,O>	empty()
default Function<I,O>	fallback(Function<? super I,? extends O> fallback)	Create a function which will fall back to the return values from fallback when this function doesn't return a value.
static <I,O> OptionalFunction<I,O>	of(Object input, Supplier<? extends O> output)
static <I,O> OptionalFunction<I,O>	of(Object input, O output)
static <I,O> OptionalFunction<I,O>	of(Map<? super I,? extends O> map)
default OptionalFunction<I,O>	override(OptionalFunction<? super I,? extends O> override)	Create a optional function where any value returned from override overrides the value this function would return.

Methods inherited from interface java.util.function.Function

andThen, apply, compose

Method Detail

empty

static <I,O> OptionalFunction<I,O> empty()

of

static <I,O> OptionalFunction<I,O> of(Map<? super I,? extends O> map)

of

static <I,O> OptionalFunction<I,O> of(Object input,
                                                  O output)

of

static <I,O> OptionalFunction<I,O> of(Object input,
                                                  Supplier<? extends O> output)

fallback

default Function<I,O> fallback(Function<? super I,? extends O> fallback)

Create a function which will fall back to the return values from fallback when this function doesn't return a value.

Parameters:

fallback - The function to call back to when this returns no value.

Returns:

A function which will return values from this or, if needed, the fallback.

See Also:

IOptionalFunctional.fallback(Function)

override

default OptionalFunction<I,O> override(OptionalFunction<? super I,? extends O> override)

Create a optional function where any value returned from override overrides the value this function would return.

Parameters:

override - The function whose return values, when any, override our own.

Returns:

An optional function which returns the results of override if any, and the result of this optional function otherwise.

See Also:

IOptionalFunctional.override(IOptionalFunctional)