Uses of Class com.google.common.base.Optional (Guava: Google Core Libraries for Java 30.0-jre API)

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	Description
`static <T> Optional<T>`	Optional.`absent()`	Returns an `Optional` instance with no contained reference.
`static <T> @Nullable Optional<T>`	Optional.`fromJavaUtil(@Nullable 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(@Nullable 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	Description
`abstract Optional<T>`	Optional.`or(Optional<? extends T> secondChoice)`	Returns this `Optional` if it has a value present; `secondChoice` otherwise.
`static <T> @Nullable Optional<T>`	Optional.`toJavaUtil(@Nullable 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	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	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.
`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	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	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	Description
`Optional<Charset>`	MediaType.`charset()`	Returns an optional charset for the value of the charset parameter if it is specified.