org.eclipse.emfforms.common

Class Optional<T>

java.lang.Object

org.eclipse.emfforms.common.Optional<T>

Type Parameters:

T - Type of the value

public final class Optional<T>
extends Object

A container object that may or may not contain a value.

Since:

1.8

Author:

Eugen Neufeld

Method Summary

Modifier and Type	Method and Description
static <T> Optional<T>	empty() Returns an empty Optional instance.
T	get() If a value is present in this Optional, returns the value, otherwise throws NoSuchElementException.
boolean	isPresent() Return true if there is a value present, otherwise false.
static <T> Optional<T>	of(T value) Returns an Optional with the specified present non-null value.
static <T> Optional<T>	ofNullable(T value) Returns an Optional describing the specified value, if non-null, otherwise returns an empty Optional.
Object	orNull() Returns the wrapped value, if present, otherwise null.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

empty

public static <T> Optional<T> empty()

Returns an empty Optional instance. No value is present for this Optional.

Type Parameters:

T - Type of the non-existent value

Returns:

an empty Optional

of

public static <T> Optional<T> of(T value)

Returns an Optional with the specified present non-null value.

Type Parameters:

T - the class of the value

Parameters:

value - the value to be present, which must be non-null

Returns:

an Optional with the value present

ofNullable

public static <T> Optional<T> ofNullable(T value)

Returns an Optional describing the specified value, if non-null, otherwise returns an empty Optional.

Type Parameters:

T - the class of the value

Parameters:

value - the possibly-null value to describe

Returns:

an Optional with a present value if the specified value is non-null, otherwise an empty Optional

isPresent

public boolean isPresent()

Return true if there is a value present, otherwise false.

Returns:

true if there is a value present, otherwise false

get

public T get()

If a value is present in this Optional, returns the value, otherwise throws NoSuchElementException.

Returns:

the non-null value held by this Optional

See Also:

isPresent()

orNull

public Object orNull()

Returns the wrapped value, if present, otherwise null.

Returns:

the wrapped value, if present, otherwise null

Since:

1.13