[−][src]Struct futures::stream::FuturesOrdered
An unbounded queue of futures.
This "combinator" is similar to FuturesUnordered
, but it imposes an order
on top of the set of futures. While futures in the set will race to
completion in parallel, results will only be returned in the order their
originating futures were added to the queue.
Futures are pushed into this queue and their realized values are yielded in
order. This structure is optimized to manage a large number of futures.
Futures managed by FuturesOrdered
will only be polled when they generate
notifications. This reduces the required amount of work needed to coordinate
large numbers of futures.
When a FuturesOrdered
is first created, it does not contain any futures.
Calling poll
in this state will result in Ok(Async::Ready(None))
to be
returned. Futures are submitted to the queue using push
; however, the
future will not be polled at this point. FuturesOrdered
will only
poll managed futures when FuturesOrdered::poll
is called. As such, it
is important to call poll
after pushing new futures.
If FuturesOrdered::poll
returns Ok(Async::Ready(None))
this means that
the queue is currently not managing any futures. A future may be submitted
to the queue at a later time. At that point, a call to
FuturesOrdered::poll
will either return the future's resolved value
or Ok(Async::NotReady)
if the future has not yet completed. When
multiple futures are submitted to the queue, FuturesOrdered::poll
will
return Ok(Async::NotReady)
until the first future completes, even if
some of the later futures have already completed.
Note that you can create a ready-made FuturesOrdered
via the
futures_ordered
function in the stream
module, or you can start with an
empty queue with the FuturesOrdered::new
constructor.
Methods
impl<T> FuturesOrdered<T> where
T: Future,
[src]
T: Future,
pub fn new() -> FuturesOrdered<T>
[src]
Constructs a new, empty FuturesOrdered
The returned FuturesOrdered
does not contain any futures and, in this
state, FuturesOrdered::poll
will return Ok(Async::Ready(None))
.
pub fn len(&self) -> usize
[src]
Returns the number of futures contained in the queue.
This represents the total number of in-flight futures, both those currently processing and those that have completed but which are waiting for earlier futures to complete.
pub fn is_empty(&self) -> bool
[src]
Returns true
if the queue contains no futures
pub fn push(&mut self, future: T)
[src]
Push a future into the queue.
This function submits the given future to the internal set for managing.
This function will not call poll
on the submitted future. The caller
must ensure that FuturesOrdered::poll
is called in order to receive
task notifications.
Trait Implementations
impl<T> Stream for FuturesOrdered<T> where
T: Future,
[src]
T: Future,
type Item = T::Item
The type of item this stream will yield on success.
type Error = T::Error
The type of error this stream may generate.
fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error>
[src]
ⓘImportant traits for Wait<S>fn wait(self) -> Wait<Self> where
Self: Sized,
[src]
Self: Sized,
fn into_future(self) -> StreamFuture<Self> where
Self: Sized,
[src]
Self: Sized,
fn map<U, F>(self, f: F) -> Map<Self, F> where
F: FnMut(Self::Item) -> U,
Self: Sized,
[src]
F: FnMut(Self::Item) -> U,
Self: Sized,
fn map_err<U, F>(self, f: F) -> MapErr<Self, F> where
F: FnMut(Self::Error) -> U,
Self: Sized,
[src]
F: FnMut(Self::Error) -> U,
Self: Sized,
fn filter<F>(self, f: F) -> Filter<Self, F> where
F: FnMut(&Self::Item) -> bool,
Self: Sized,
[src]
F: FnMut(&Self::Item) -> bool,
Self: Sized,
fn filter_map<F, B>(self, f: F) -> FilterMap<Self, F> where
F: FnMut(Self::Item) -> Option<B>,
Self: Sized,
[src]
F: FnMut(Self::Item) -> Option<B>,
Self: Sized,
fn then<F, U>(self, f: F) -> Then<Self, F, U> where
F: FnMut(Result<Self::Item, Self::Error>) -> U,
U: IntoFuture,
Self: Sized,
[src]
F: FnMut(Result<Self::Item, Self::Error>) -> U,
U: IntoFuture,
Self: Sized,
fn and_then<F, U>(self, f: F) -> AndThen<Self, F, U> where
F: FnMut(Self::Item) -> U,
U: IntoFuture<Error = Self::Error>,
Self: Sized,
[src]
F: FnMut(Self::Item) -> U,
U: IntoFuture<Error = Self::Error>,
Self: Sized,
fn or_else<F, U>(self, f: F) -> OrElse<Self, F, U> where
F: FnMut(Self::Error) -> U,
U: IntoFuture<Item = Self::Item>,
Self: Sized,
[src]
F: FnMut(Self::Error) -> U,
U: IntoFuture<Item = Self::Item>,
Self: Sized,
fn collect(self) -> Collect<Self> where
Self: Sized,
[src]
Self: Sized,
fn concat2(self) -> Concat2<Self> where
Self: Sized,
Self::Item: Extend<<Self::Item as IntoIterator>::Item> + IntoIterator + Default,
[src]
Self: Sized,
Self::Item: Extend<<Self::Item as IntoIterator>::Item> + IntoIterator + Default,
fn concat(self) -> Concat<Self> where
Self: Sized,
Self::Item: Extend<<Self::Item as IntoIterator>::Item> + IntoIterator,
[src]
Self: Sized,
Self::Item: Extend<<Self::Item as IntoIterator>::Item> + IntoIterator,
fn fold<F, T, Fut>(self, init: T, f: F) -> Fold<Self, F, Fut, T> where
F: FnMut(T, Self::Item) -> Fut,
Fut: IntoFuture<Item = T>,
Self::Error: From<Fut::Error>,
Self: Sized,
[src]
F: FnMut(T, Self::Item) -> Fut,
Fut: IntoFuture<Item = T>,
Self::Error: From<Fut::Error>,
Self: Sized,
fn flatten(self) -> Flatten<Self> where
Self::Item: Stream,
<Self::Item as Stream>::Error: From<Self::Error>,
Self: Sized,
[src]
Self::Item: Stream,
<Self::Item as Stream>::Error: From<Self::Error>,
Self: Sized,
fn skip_while<P, R>(self, pred: P) -> SkipWhile<Self, P, R> where
P: FnMut(&Self::Item) -> R,
R: IntoFuture<Item = bool, Error = Self::Error>,
Self: Sized,
[src]
P: FnMut(&Self::Item) -> R,
R: IntoFuture<Item = bool, Error = Self::Error>,
Self: Sized,
fn take_while<P, R>(self, pred: P) -> TakeWhile<Self, P, R> where
P: FnMut(&Self::Item) -> R,
R: IntoFuture<Item = bool, Error = Self::Error>,
Self: Sized,
[src]
P: FnMut(&Self::Item) -> R,
R: IntoFuture<Item = bool, Error = Self::Error>,
Self: Sized,
fn for_each<F, U>(self, f: F) -> ForEach<Self, F, U> where
F: FnMut(Self::Item) -> U,
U: IntoFuture<Item = (), Error = Self::Error>,
Self: Sized,
[src]
F: FnMut(Self::Item) -> U,
U: IntoFuture<Item = (), Error = Self::Error>,
Self: Sized,
fn from_err<E: From<Self::Error>>(self) -> FromErr<Self, E> where
Self: Sized,
[src]
Self: Sized,
fn take(self, amt: u64) -> Take<Self> where
Self: Sized,
[src]
Self: Sized,
fn skip(self, amt: u64) -> Skip<Self> where
Self: Sized,
[src]
Self: Sized,
fn fuse(self) -> Fuse<Self> where
Self: Sized,
[src]
Self: Sized,
fn by_ref(&mut self) -> &mut Self where
Self: Sized,
[src]
Self: Sized,
fn catch_unwind(self) -> CatchUnwind<Self> where
Self: Sized + UnwindSafe,
[src]
Self: Sized + UnwindSafe,
fn buffered(self, amt: usize) -> Buffered<Self> where
Self::Item: IntoFuture<Error = Self::Error>,
Self: Sized,
[src]
Self::Item: IntoFuture<Error = Self::Error>,
Self: Sized,
fn buffer_unordered(self, amt: usize) -> BufferUnordered<Self> where
Self::Item: IntoFuture<Error = Self::Error>,
Self: Sized,
[src]
Self::Item: IntoFuture<Error = Self::Error>,
Self: Sized,
fn merge<S>(self, other: S) -> Merge<Self, S> where
S: Stream<Error = Self::Error>,
Self: Sized,
[src]
S: Stream<Error = Self::Error>,
Self: Sized,
fn zip<S>(self, other: S) -> Zip<Self, S> where
S: Stream<Error = Self::Error>,
Self: Sized,
[src]
S: Stream<Error = Self::Error>,
Self: Sized,
fn chain<S>(self, other: S) -> Chain<Self, S> where
S: Stream<Item = Self::Item, Error = Self::Error>,
Self: Sized,
[src]
S: Stream<Item = Self::Item, Error = Self::Error>,
Self: Sized,
fn peekable(self) -> Peekable<Self> where
Self: Sized,
[src]
Self: Sized,
fn chunks(self, capacity: usize) -> Chunks<Self> where
Self: Sized,
[src]
Self: Sized,
fn select<S>(self, other: S) -> Select<Self, S> where
S: Stream<Item = Self::Item, Error = Self::Error>,
Self: Sized,
[src]
S: Stream<Item = Self::Item, Error = Self::Error>,
Self: Sized,
fn forward<S>(self, sink: S) -> Forward<Self, S> where
S: Sink<SinkItem = Self::Item>,
Self::Error: From<S::SinkError>,
Self: Sized,
[src]
S: Sink<SinkItem = Self::Item>,
Self::Error: From<S::SinkError>,
Self: Sized,
fn split(self) -> (SplitSink<Self>, SplitStream<Self>) where
Self: Sink + Sized,
[src]
Self: Sink + Sized,
fn inspect<F>(self, f: F) -> Inspect<Self, F> where
F: FnMut(&Self::Item),
Self: Sized,
[src]
F: FnMut(&Self::Item),
Self: Sized,
fn inspect_err<F>(self, f: F) -> InspectErr<Self, F> where
F: FnMut(&Self::Error),
Self: Sized,
[src]
F: FnMut(&Self::Error),
Self: Sized,
impl<T: Debug> Debug for FuturesOrdered<T> where
T: Future,
[src]
T: Future,
impl<F: Future> FromIterator<F> for FuturesOrdered<F>
[src]
fn from_iter<T>(iter: T) -> Self where
T: IntoIterator<Item = F>,
[src]
T: IntoIterator<Item = F>,
impl<T> Default for FuturesOrdered<T> where
T: Future,
[src]
T: Future,
Auto Trait Implementations
impl<T> Unpin for FuturesOrdered<T> where
<T as Future>::Item: Unpin,
<T as Future>::Item: Unpin,
impl<T> Send for FuturesOrdered<T> where
T: Send,
<T as Future>::Item: Send,
T: Send,
<T as Future>::Item: Send,
impl<T> Sync for FuturesOrdered<T> where
T: Sync,
<T as Future>::Item: Sync,
T: Sync,
<T as Future>::Item: Sync,
impl<T> !UnwindSafe for FuturesOrdered<T>
impl<T> !RefUnwindSafe for FuturesOrdered<T>
Blanket Implementations
impl<T> From<T> for T
[src]
impl<T, U> TryFrom<U> for T where
U: Into<T>,
[src]
U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
[src]
impl<T, U> Into<U> for T where
U: From<T>,
[src]
U: From<T>,
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
[src]
U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
[src]
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
[src]
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,