org.littleshoot.util
Interface OptionalUtils

All Known Implementing Classes:

OptionalUtilsImpl

public interface OptionalUtils

Utilities for working with Optional objects.

Method Summary

<T> void	executeOnSome(Optional<T> optional, Closure<T> closure) Executes a given closure on an optional object.
<T> Collection<T>	filterNones(Collection<Optional<T>> c) Filters out the None elements in a collection and returns a collection of the objects inside the remaining Some elements.
<T> boolean	isNone(Optional<T> optional) Returns whether an optional object is a None object.
boolean	isSome(Optional optional) Returns whether an optional object is a Some object.
Optional	optionalOf(Object object) Returns an Optional from a possible null object.
<T> T	someObject(Optional<T> optional) Returns the object stored in an optional object if one exists.
<T1,T2> Optional<T2>	transformSome(Optional<T1> optional, Transformer<T1,T2> transformer) Returns an Optional object created by transforming the contents of another Optional object.

Method Detail

optionalOf

Optional optionalOf(Object object)

Returns an Optional from a possible null object. If the object is null, None is returned. Otherwise, a Some object containing the given object is returned.

Parameters:

object - The object, possible null.

Returns:

If object is null, then None is returned, otherwise a Some containing object is returned.

transformSome

<T1,T2> Optional<T2> transformSome(Optional<T1> optional,
                                   Transformer<T1,T2> transformer)

Returns an Optional object created by transforming the contents of another Optional object. If the given Optional is a None, then None is returned. If the given Optional is a Some, then the contents of the Some are transformed and the result wrapped in a Some is returned.

Parameters:

optional - The Optional object to be transformed.

transformer - The transformer used to transform the contents of a Some object.

Returns:

An Optional object whose contents, if they exists, have been transformed by the given transformer.

isNone

<T> boolean isNone(Optional<T> optional)

Returns whether an optional object is a None object.

Parameters:

optional - The optional object.

Returns:

True if optional is a None, false otherwise.

isSome

boolean isSome(Optional optional)

Returns whether an optional object is a Some object.

Parameters:

optional - The optional object.

Returns:

True if optional is a Some, false otherwise.

someObject

<T> T someObject(Optional<T> optional)
             throws IllegalArgumentException

Returns the object stored in an optional object if one exists. Otherwise, an exception is thrown.

Parameters:

optional - The optional object.

Returns:

The object stored in the optional object, if it exists.

Throws:

IllegalArgumentException - If the optional object is not a Some object.

executeOnSome

<T> void executeOnSome(Optional<T> optional,
                       Closure<T> closure)

Executes a given closure on an optional object.

Type Parameters:

T - The type of object held by the optional object.

Parameters:

optional - The optional object.

closure - The closure to execute on the object held by the optional object, if it exists.

filterNones

<T> Collection<T> filterNones(Collection<Optional<T>> c)

Filters out the None elements in a collection and returns a collection of the objects inside the remaining Some elements.

Type Parameters:

T - The type of the objects inside the some objects.

Parameters:

c - The collection to filter.

Returns:

A collection of type T elements.