Struct Keyed

pub struct Keyed<F: Future> { /* private fields */ }

Iterate over items in the futures group with their associated keys.

Methods from Deref<Target = FutureGroup<F>>

pub fn len(&self) -> usize

Return the number of futures currently active in the group.

Example

use futures_concurrency::future::FutureGroup;
use futures_lite::StreamExt;
use std::future;

let mut group = FutureGroup::with_capacity(2);
assert_eq!(group.len(), 0);
group.insert(future::ready(12));
assert_eq!(group.len(), 1);

pub fn capacity(&self) -> usize

Return the capacity of the FutureGroup.

Example

use futures_concurrency::future::FutureGroup;
use futures_lite::stream;

let group = FutureGroup::with_capacity(2);
assert_eq!(group.capacity(), 2);

pub fn is_empty(&self) -> bool

Returns true if there are no futures currently active in the group.

Example

use futures_concurrency::future::FutureGroup;
use std::future;

let mut group = FutureGroup::with_capacity(2);
assert!(group.is_empty());
group.insert(future::ready(12));
assert!(!group.is_empty());

pub fn remove(&mut self, key: Key) -> bool

Removes a stream from the group. Returns whether the value was present in the group.

Example

use futures_concurrency::future::FutureGroup;
use std::future;

let mut group = FutureGroup::new();
let key = group.insert(future::ready(4));
assert_eq!(group.len(), 1);
group.remove(key);
assert_eq!(group.len(), 0);

pub fn contains_key(&mut self, key: Key) -> bool

Returns true if the FutureGroup contains a value for the specified key.

Example

use futures_concurrency::future::FutureGroup;
use std::future;

let mut group = FutureGroup::new();
let key = group.insert(future::ready(4));
assert!(group.contains_key(key));
group.remove(key);
assert!(!group.contains_key(key));

pub fn reserve(&mut self, additional: usize)

Reserves capacity for additional more futures to be inserted. Does nothing if the capacity is already sufficient.

Example

use futures_concurrency::future::FutureGroup;
use std::future::Ready;
let mut group: FutureGroup<Ready<usize>> = FutureGroup::with_capacity(0);
assert_eq!(group.capacity(), 0);
group.reserve(10);
assert_eq!(group.capacity(), 10);

// does nothing if capacity is sufficient
group.reserve(5);
assert_eq!(group.capacity(), 10);

pub fn insert(&mut self, future: F) -> Key

where F: Future,

Insert a new future into the group.

Example

use futures_concurrency::future::FutureGroup;
use std::future;

let mut group = FutureGroup::with_capacity(2);
group.insert(future::ready(12));

Trait Implementations

impl<F: Debug + Future> Debug for Keyed<F>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<F: Future> Deref for Keyed<F>

type Target = FutureGroup<F>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<F: Future> DerefMut for Keyed<F>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<F: Future> Stream for Keyed<F>

type Item = (Key, <F as Future>::Output)

Values yielded by the stream.

fn poll_next( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Option<Self::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream.

impl<'pin, F: Future> Unpin for Keyed<F>

where __Keyed<'pin, F>: Unpin,