Uses of Class
com.google.common.base.Optional

Packages that use Optional

Package	Description
com.google.common.base	Basic utility libraries and interfaces.
com.google.common.collect	This package contains generic collection interfaces and implementations, and other utilities for working with collections.
com.google.common.io	This package contains utility methods and classes for working with Java I/O; for example input streams, output streams, readers, writers, and files.
com.google.common.net	This package contains utility methods and classes for working with net addresses (numeric IP and domain names).

Uses of Optional in com.google.common.base

Methods in com.google.common.base that return Optional

Modifier and Type	Method and Description
static <T> Optional<T>	Optional.absent() Returns an Optional instance with no contained reference.
static <T> Optional<T>	Optional.fromJavaUtil(Optional<T> javaUtilOptional) Returns the equivalent com.google.common.base.Optional value to the given java.util.Optional, or null if the argument is null.
static <T> Optional<T>	Optional.fromNullable(T nullableReference) If nullableReference is non-null, returns an Optional instance containing that reference; otherwise returns absent().
static <T extends Enum<T>> Optional<T>	Enums.getIfPresent(Class<T> enumClass, String value) Returns an optional enum constant for the given type, using Enum.valueOf(java.lang.Class<T>, java.lang.String).
static <T> Optional<T>	Optional.of(T reference) Returns an Optional instance containing the given non-null reference.
abstract Optional<T>	Optional.or(Optional<? extends T> secondChoice) Returns this Optional if it has a value present; secondChoice otherwise.
abstract <V> Optional<V>	Optional.transform(Function<? super T,V> function) If the instance is present, it is transformed with the given Function; otherwise, absent() is returned.

Methods in com.google.common.base with parameters of type Optional

Modifier and Type	Method and Description
abstract Optional<T>	Optional.or(Optional<? extends T> secondChoice) Returns this Optional if it has a value present; secondChoice otherwise.
static <T> Optional<T>	Optional.toJavaUtil(Optional<T> googleOptional) Returns the equivalent java.util.Optional value to the given com.google.common.base.Optional, or null if the argument is null.

Method parameters in com.google.common.base with type arguments of type Optional

Modifier and Type	Method and Description
static <T> Iterable<T>	Optional.presentInstances(Iterable<? extends Optional<? extends T>> optionals) Returns the value of each present instance from the supplied optionals, in order, skipping over occurrences of absent().

Uses of Optional in com.google.common.collect

Methods in com.google.common.collect that return Optional

Modifier and Type	Method and Description
Optional<E>	FluentIterable.first() Returns an Optional containing the first element in this fluent iterable.
Optional<E>	FluentIterable.firstMatch(Predicate<? super E> predicate) Returns an Optional containing the first element in this fluent iterable that satisfies the given predicate, if such an element exists.
Optional<E>	FluentIterable.last() Returns an Optional containing the last element in this fluent iterable.
abstract Optional<T>	BinaryTreeTraverser.leftChild(T root) Returns the left child of the specified node, or absent() if the specified node has no left child.
abstract Optional<T>	BinaryTreeTraverser.rightChild(T root) Returns the right child of the specified node, or absent() if the specified node has no right child.
static <T> Optional<T>	Iterables.tryFind(Iterable<T> iterable, Predicate<? super T> predicate) Returns an Optional containing the first element in iterable that satisfies the given predicate, if such an element exists.
static <T> Optional<T>	Iterators.tryFind(Iterator<T> iterator, Predicate<? super T> predicate) Returns an Optional containing the first element in iterator that satisfies the given predicate, if such an element exists.

Methods in com.google.common.collect with parameters of type Optional

Modifier and Type	Method and Description
static <T> Stream<T>	Streams.stream(Optional<T> optional) If a value is present in optional, returns a stream containing only that element, otherwise returns an empty stream.

Uses of Optional in com.google.common.io

Methods in com.google.common.io that return Optional

Modifier and Type	Method and Description
Optional<Long>	CharSource.lengthIfKnown() Returns the size of this source in chars, if the size can be easily determined without actually opening the data stream.
Optional<Long>	ByteSource.sizeIfKnown() Returns the size of this source in bytes, if the size can be easily determined without actually opening the data stream.

Uses of Optional in com.google.common.net

Methods in com.google.common.net that return Optional

Modifier and Type	Method and Description
Optional<Charset>	MediaType.charset() Returns an optional charset for the value of the charset parameter if it is specified.