Struct Optional 

pub struct Optional<T>(/* private fields */);

java/util/Optional

Implementations

impl<T> Optional<T>

where T: Object,

pub fn of(e: &mut Env<'_>, t: T) -> Self

java.util.Optional$of

pub fn empty(e: &mut Env<'_>) -> Self

Create an empty instance of Optional<T>

pub fn is_empty(&self, e: &mut Env<'_>) -> bool

Is this Optional empty? (equivalent to [Option.is_none])

pub fn get(&self, e: &mut Env<'_>) -> T

Extract the value from the optional, throwing a Java exception if it was empty.

(equivalent to [Option.unwrap])

pub fn to_option(self, e: &mut Env<'_>) -> Option<T>

Infallibly convert this java Optional<T> to a rust Option<T>.

pub fn from_option(o: Option<T>, e: &mut Env<'_>) -> Self

Infallibly convert create a java Optional<T> from a rust Option<T>.

Trait Implementations

impl<T> Class for Optional<T>

where T: Object,

const PATH: &'static str = "java/util/Optional"

The fully qualified java class path (slash-separated)

impl<T> Object for Optional<T>

where T: Object,

fn upcast(_e: &mut Env<'_>, jobj: Object) -> Self

Try to interpret an object as Self

fn downcast(self, _e: &mut Env<'_>) -> Object

Create an object reference from self

fn downcast_ref(&self, e: &mut Env<'_>) -> Object

Create an object reference from &self

fn upcast_value_ref<'e>(e: &mut Env<'e>, jv: JValue<'e, '_>) -> Self

where Self: Sized,

Try to interpret a JValue as Self

fn upcast_value<'e>(e: &mut Env<'e>, jv: JValueOwned<'e>) -> Self

where Self: Sized,

Try to interpret a JValueOwned as Self

fn downcast_value<'e>(self, e: &mut Env<'e>) -> JValueOwned<'e>

where Self: Sized,

Create a JValueOwned from self

fn yield_to_java(&self, e: &mut Env<'_>) -> jobject

Use this to yield ownership of a java::lang::Object to the JVM, for example when returning a jobject from a native function.