Class AbstractPushStreamImpl<T>
- All Implemented Interfaces:
AutoCloseable
,PushStream<T>
- Direct Known Subclasses:
IntermediatePushStreamImpl
,UnbufferedPushStreamImpl
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate static class
(package private) static enum
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected final AtomicReference
<AbstractPushStreamImpl.State> protected final AtomicReference
<PushEventConsumer<T>> protected final AtomicReference
<Runnable> protected final AtomicReference
<Consumer<? super Throwable>> protected final PromiseFactory
protected final PushStreamProvider
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Constructor Summary
ConstructorsConstructorDescriptionAbstractPushStreamImpl
(PushStreamProvider psp, PromiseFactory promiseFactory) -
Method Summary
Modifier and TypeMethodDescriptionadjustBackPressure
(LongUnaryOperator adjustment) Changes the back-pressure propagated by this pipeline stage.adjustBackPressure
(ToLongBiFunction<T, Long> adjustment) Changes the back-pressure propagated by this pipeline stage.private <R> void
aggregateAndForward
(BiFunction<Long, Collection<T>, R> f, AbstractPushStreamImpl<R> eventStream, PushEvent<? extends T> event, Queue<T> queue, Executor executor, long elapsed) private <R> long
aggregateAndForward
(Function<Collection<T>, R> f, AbstractPushStreamImpl<R> eventStream, PushEvent<? extends T> event, Queue<T> queue) Closes the channel and resolve the promise with false when the predicate does not matches a pay load.Close the channel and resolve the promise with true when the predicate matches a payload.<R> PushStream
<R> Asynchronously map the payload values.protected abstract boolean
begin()
buffer()
Buffer the events in a queue using default values for the queue size and other behaviors.<U extends BlockingQueue<PushEvent<? extends T>>>
PushStreamBuilder<T, U> Build a buffer to enqueue events in a queue using custom values for the queue size and other behaviors.(package private) void
check
(AtomicLong lastTime, long timeout) void
close()
Close this PushStream by sending an event of typePushEvent.EventType.CLOSE
downstream.protected boolean
protected boolean
<R> PushStream
<R> coalesce
(int count, Function<Collection<T>, R> f) Coalesces a number of events into a new type of event.<R> PushStream
<R> coalesce
(IntSupplier count, Function<Collection<T>, R> f) Coalesces a number of events into a new type of event.<R> PushStream
<R> Coalesces a number of events into a new type of event.<R,
A> Promise <R> See Stream.count()
See Stream.distinct()
Remove any duplicates.Only pass events downstream when the predicate tests true.findAny()
Close the channel and resolve the promise with the first element.Close the channel and resolve the promise with the first element.<R> PushStream
<R> flatMap
(Function<? super T, ? extends PushStream<? extends R>> mapper) Flat map the payload value (turn one event into 0..n events of potentially another type).Execute the action for each event received until the channel is closed.forEachEvent
(PushEventConsumer<? super T> action) Pass on each event to another consumer until the stream is closed.Execute the downstream events in up to n background threads.getQueueForInternalBuffering
(int size) private <R> Runnable
getWindowTask
(AbstractPushStreamImpl<R> eventStream, BiFunction<Long, Collection<T>, R> f, Supplier<Duration> time, IntSupplier maxEvents, Object lock, long expectedCounter, AtomicReference<Queue<T>> queueRef, AtomicLong timestamp, AtomicLong counter, AtomicLong previousWindowSize, Executor executor) protected long
handleEvent
(PushEvent<? extends T> event) limit
(long maxSize) Automatically close the channel after the maxSize number of elements is received.Automatically close the channel after the given amount of time has elapsed.<R> PushStream
<R> Map a payload value.max
(Comparator<? super T> comparator) See Stream.merge
(PushEventSource<? extends T> source) Merge in the events from another source.merge
(PushStream<? extends T> source) Merge in the events from another PushStream.min
(Comparator<? super T> comparator) See Stream.Closes the channel and resolve the promise with false when the predicate matches any pay load.Must be run after the channel is closed.Must be run after the channel is closed.reduce
(BinaryOperator<T> accumulator) Standard reduce without identity, so the return is an Optional.reduce
(T identity, BinaryOperator<T> accumulator) Standard reduce, see Stream.<U> Promise
<U> reduce
(U identity, BiFunction<U, ? super T, U> accumulator, BinaryOperator<U> combiner) Standard reduce with identity, accumulator and combiner.Ensure that any events are delivered sequentially.skip
(long n) Skip a number of events in the channel.sorted()
Sorted the elements, assuming that T extends Comparable.sorted
(Comparator<? super T> comparator) Sorted the elements with the given comparator.PushStream<T>[]
Split the events to different streams based on a predicate.Automatically fail the channel if no events are received for the indicated length of time.toArray()
Collect the payloads in an Object array after the channel is closed.toArray
(IntFunction<A[]> generator) Collect the payloads in an Object array after the channel is closed.private void
updateNext
(PushEventConsumer<T> consumer) protected abstract void
upstreamClose
(PushEvent<?> close) <R> PushStream
<R> Buffers a number of events over a fixed time interval and then forwards the events to an accumulator function.<R> PushStream
<R> window
(Duration time, Function<Collection<T>, R> f) Buffers a number of events over a fixed time interval and then forwards the events to an accumulator function.<R> PushStream
<R> window
(Supplier<Duration> time, IntSupplier maxEvents, Executor ex, BiFunction<Long, Collection<T>, R> f) Buffers a number of events over a variable time interval and then forwards the events to an accumulator function.<R> PushStream
<R> window
(Supplier<Duration> time, IntSupplier maxEvents, BiFunction<Long, Collection<T>, R> f) Buffers a number of events over a variable time interval and then forwards the events to an accumulator function.
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Field Details
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IDENTITY
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psp
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promiseFactory
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closed
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next
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onCloseCallback
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onErrorCallback
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Constructor Details
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AbstractPushStreamImpl
AbstractPushStreamImpl(PushStreamProvider psp, PromiseFactory promiseFactory)
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Method Details
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begin
protected abstract boolean begin() -
upstreamClose
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handleEvent
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close
public void close()Description copied from interface:PushStream
Close this PushStream by sending an event of typePushEvent.EventType.CLOSE
downstream. Closing a PushStream is a safe operation that will not throw an Exception.Calling
close()
on a closed PushStream has no effect.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfacePushStream<T>
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close
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close
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onClose
Description copied from interface:PushStream
Must be run after the channel is closed. This handler will run after the downstream methods have processed the close event and before the upstream methods have closed.- Specified by:
onClose
in interfacePushStream<T>
- Parameters:
closeHandler
- Will be called on close- Returns:
- This stream
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onError
Description copied from interface:PushStream
Must be run after the channel is closed. This handler will run after the downstream methods have processed the close event and before the upstream methods have closed.- Specified by:
onError
in interfacePushStream<T>
- Parameters:
closeHandler
- Will be called on close- Returns:
- This stream
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updateNext
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filter
Description copied from interface:PushStream
Only pass events downstream when the predicate tests true.- Specified by:
filter
in interfacePushStream<T>
- Parameters:
predicate
- The predicate that is tested (not null)- Returns:
- Builder style (can be a new or the same object)
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map
Description copied from interface:PushStream
Map a payload value.- Specified by:
map
in interfacePushStream<T>
- Parameters:
mapper
- The map function- Returns:
- Builder style (can be a new or the same object)
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asyncMap
public <R> PushStream<R> asyncMap(int n, int delay, Function<? super T, Promise<? extends R>> mapper) Description copied from interface:PushStream
Asynchronously map the payload values. The mapping function returns a Promise representing the asynchronous mapping operation.The PushStream limits the number of concurrently running mapping operations, and returns back pressure based on the number of existing queued operations.
- Specified by:
asyncMap
in interfacePushStream<T>
- Parameters:
n
- number of simultaneous promises to usedelay
- Nr of ms/promise that is queued back pressuremapper
- The mapping function- Returns:
- Builder style (can be a new or the same object)
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flatMap
Description copied from interface:PushStream
Flat map the payload value (turn one event into 0..n events of potentially another type).- Specified by:
flatMap
in interfacePushStream<T>
- Parameters:
mapper
- The flat map function- Returns:
- Builder style (can be a new or the same object)
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distinct
Description copied from interface:PushStream
Remove any duplicates. Notice that this can be expensive in a large stream since it must track previous payloads.- Specified by:
distinct
in interfacePushStream<T>
- Returns:
- Builder style (can be a new or the same object)
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sorted
Description copied from interface:PushStream
Sorted the elements, assuming that T extends Comparable. This is of course expensive for large or infinite streams since it requires buffering the stream until close.- Specified by:
sorted
in interfacePushStream<T>
- Returns:
- Builder style (can be a new or the same object)
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sorted
Description copied from interface:PushStream
Sorted the elements with the given comparator. This is of course expensive for large or infinite streams since it requires buffering the stream until close.- Specified by:
sorted
in interfacePushStream<T>
- Parameters:
comparator
-- Returns:
- Builder style (can be a new or the same object)
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limit
Description copied from interface:PushStream
Automatically close the channel after the maxSize number of elements is received.- Specified by:
limit
in interfacePushStream<T>
- Parameters:
maxSize
- Maximum number of elements has been received- Returns:
- Builder style (can be a new or the same object)
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limit
Description copied from interface:PushStream
Automatically close the channel after the given amount of time has elapsed.- Specified by:
limit
in interfacePushStream<T>
- Parameters:
maxTime
- The maximum time that the stream should remain open- Returns:
- Builder style (can be a new or the same object)
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timeout
Description copied from interface:PushStream
Automatically fail the channel if no events are received for the indicated length of time. If the timeout is reached then a failure event containing aTimeoutException
will be sent.- Specified by:
timeout
in interfacePushStream<T>
- Parameters:
maxTime
- The length of time that the stream should remain open when no events are being received.- Returns:
- Builder style (can be a new or the same object)
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check
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skip
Description copied from interface:PushStream
Skip a number of events in the channel.- Specified by:
skip
in interfacePushStream<T>
- Parameters:
n
- number of elements to skip- Returns:
- Builder style (can be a new or the same object)
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fork
Description copied from interface:PushStream
Execute the downstream events in up to n background threads. If more requests are outstanding apply delay * nr of delayed threads back pressure. A downstream channel that is closed or throws an exception will cause all execution to cease and the stream to close- Specified by:
fork
in interfacePushStream<T>
- Parameters:
n
- number of simultaneous background threads to usedelay
- Nr of ms/thread that is queued back pressureex
- an executor to use for the background threads.- Returns:
- Builder style (can be a new or the same object)
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buffer
Description copied from interface:PushStream
Buffer the events in a queue using default values for the queue size and other behaviors. Buffered work will be processed asynchronously in the rest of the chain. Buffering also blocks the transmission of back pressure to previous elements in the chain, although back pressure is honored by the buffer.Buffers are useful for "bursty" event sources which produce a number of events close together, then none for some time. These bursts can sometimes overwhelm downstream event consumers. Buffering will not, however, protect downstream components from a source which produces events faster than they can be consumed. For fast sources
PushStream.filter(Predicate)
andPushStream.coalesce(int, Function)
PushStream.fork(int, int, Executor)
are better choices.- Specified by:
buffer
in interfacePushStream<T>
- Returns:
- Builder style (can be a new or the same object)
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buildBuffer
Description copied from interface:PushStream
Build a buffer to enqueue events in a queue using custom values for the queue size and other behaviors. Buffered work will be processed asynchronously in the rest of the chain. Buffering also blocks the transmission of back pressure to previous elements in the chain, although back pressure is honored by the buffer.Buffers are useful for "bursty" event sources which produce a number of events close together, then none for some time. These bursts can sometimes overwhelm downstream event consumers. Buffering will not, however, protect downstream components from a source which produces events faster than they can be consumed. For fast sources
PushStream.filter(Predicate)
andPushStream.coalesce(int, Function)
PushStream.fork(int, int, Executor)
are better choices.Buffers are also useful as "circuit breakers" in the pipeline. If a
QueuePolicyOption.FAIL
is used then a full buffer will trigger the stream to close, preventing an event storm from reaching the client.- Specified by:
buildBuffer
in interfacePushStream<T>
- Returns:
- A builder which can be used to configure the buffer for this pipeline stage.
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merge
Description copied from interface:PushStream
Merge in the events from another source. The resulting channel is not closed until this channel and the channel from the source are closed.- Specified by:
merge
in interfacePushStream<T>
- Parameters:
source
- The source to merge in.- Returns:
- Builder style (can be a new or the same object)
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merge
Description copied from interface:PushStream
Merge in the events from another PushStream. The resulting channel is not closed until this channel and the channel from the source are closed.- Specified by:
merge
in interfacePushStream<T>
- Parameters:
source
- The source to merge in.- Returns:
- Builder style (can be a new or the same object)
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split
Description copied from interface:PushStream
Split the events to different streams based on a predicate. If the predicate is true, the event is dispatched to that channel on the same position. All predicates are tested for every event.This method differs from other methods of PushStream in three significant ways:
- The return value contains multiple streams.
- This stream will only close when all of these child streams have closed.
- Event delivery is made to all open children that accept the event.
- Specified by:
split
in interfacePushStream<T>
- Parameters:
predicates
- the predicates to test- Returns:
- streams that map to the predicates
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sequential
Description copied from interface:PushStream
Ensure that any events are delivered sequentially. That is, no overlapping calls downstream. This can be used to turn a forked stream (where for example a heavy conversion is done in multiple threads) back into a sequential stream so a reduce is simple to do.- Specified by:
sequential
in interfacePushStream<T>
- Returns:
- Builder style (can be a new or the same object)
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coalesce
Description copied from interface:PushStream
Coalesces a number of events into a new type of event. The input events are forwarded to a accumulator function. This function returns an Optional. If the optional is present, it's value is send downstream, otherwise it is ignored.- Specified by:
coalesce
in interfacePushStream<T>
- Parameters:
accumulator
-- Returns:
- Builder style (can be a new or the same object)
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coalesce
Description copied from interface:PushStream
Coalesces a number of events into a new type of event. A fixed number of input events are forwarded to a accumulator function. This function returns new event data to be forwarded on.- Specified by:
coalesce
in interfacePushStream<T>
- Parameters:
count
-f
-- Returns:
- Builder style (can be a new or the same object)
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coalesce
Description copied from interface:PushStream
Coalesces a number of events into a new type of event. A variable number of input events are forwarded to a accumulator function. The number of events to be forwarded is determined by calling the count function. The accumulator function then returns new event data to be forwarded on.- Specified by:
coalesce
in interfacePushStream<T>
- Parameters:
count
-f
-- Returns:
- Builder style (can be a new or the same object)
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aggregateAndForward
private <R> long aggregateAndForward(Function<Collection<T>, R> f, AbstractPushStreamImpl<R> eventStream, PushEvent<? extends T> event, Queue<T> queue) throws Exception- Throws:
Exception
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window
Description copied from interface:PushStream
Buffers a number of events over a fixed time interval and then forwards the events to an accumulator function. This function returns new event data to be forwarded on. Note that:- The collection forwarded to the accumulator function will be empty if no events arrived during the time interval.
- The accumulator function will be run and the forwarded event
delivered as a different task, (and therefore potentially on a different
thread) from the one that delivered the event to this
PushStream
. - Due to the buffering and asynchronous delivery required, this method prevents the propagation of back-pressure to earlier stages
- Specified by:
window
in interfacePushStream<T>
- Parameters:
time
-f
-- Returns:
- Builder style (can be a new or the same object)
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window
Description copied from interface:PushStream
Buffers a number of events over a fixed time interval and then forwards the events to an accumulator function. This function returns new event data to be forwarded on. Note that:- The collection forwarded to the accumulator function will be empty if no events arrived during the time interval.
- The accumulator function will be run and the forwarded event delivered by a task given to the supplied executor.
- Due to the buffering and asynchronous delivery required, this method prevents the propagation of back-pressure to earlier stages
- Specified by:
window
in interfacePushStream<T>
- Parameters:
time
-executor
-f
-- Returns:
- Builder style (can be a new or the same object)
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window
public <R> PushStream<R> window(Supplier<Duration> time, IntSupplier maxEvents, BiFunction<Long, Collection<T>, R> f) Description copied from interface:PushStream
Buffers a number of events over a variable time interval and then forwards the events to an accumulator function. The length of time over which events are buffered is determined by the time function. A maximum number of events can also be requested, if this number of events is reached then the accumulator will be called early. The accumulator function returns new event data to be forwarded on. It is also given the length of time for which the buffer accumulated data. This may be less than the requested interval if the buffer reached the maximum number of requested events early. Note that:- The collection forwarded to the accumulator function will be empty if no events arrived during the time interval.
- The accumulator function will be run and the forwarded event
delivered as a different task, (and therefore potentially on a different
thread) from the one that delivered the event to this
PushStream
. - Due to the buffering and asynchronous delivery required, this method prevents the propagation of back-pressure to earlier stages
- If the window finishes by hitting the maximum number of events then the remaining time in the window will be applied as back-pressure to the previous stage, attempting to slow the producer to the expected windowing threshold.
- Specified by:
window
in interfacePushStream<T>
- Parameters:
time
-maxEvents
-f
-- Returns:
- Builder style (can be a new or the same object)
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window
public <R> PushStream<R> window(Supplier<Duration> time, IntSupplier maxEvents, Executor ex, BiFunction<Long, Collection<T>, R> f) Description copied from interface:PushStream
Buffers a number of events over a variable time interval and then forwards the events to an accumulator function. The length of time over which events are buffered is determined by the time function. A maximum number of events can also be requested, if this number of events is reached then the accumulator will be called early. The accumulator function returns new event data to be forwarded on. It is also given the length of time for which the buffer accumulated data. This may be less than the requested interval if the buffer reached the maximum number of requested events early. Note that:- The collection forwarded to the accumulator function will be empty if no events arrived during the time interval.
- The accumulator function will be run and the forwarded event
delivered as a different task, (and therefore potentially on a different
thread) from the one that delivered the event to this
PushStream
. - If the window finishes by hitting the maximum number of events then the remaining time in the window will be applied as back-pressure to the previous stage, attempting to slow the producer to the expected windowing threshold.
- Specified by:
window
in interfacePushStream<T>
- Parameters:
time
-maxEvents
-ex
-f
-- Returns:
- Builder style (can be a new or the same object)
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getQueueForInternalBuffering
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getWindowTask
private <R> Runnable getWindowTask(AbstractPushStreamImpl<R> eventStream, BiFunction<Long, Collection<T>, R> f, Supplier<Duration> time, IntSupplier maxEvents, Object lock, long expectedCounter, AtomicReference<Queue<T>> queueRef, AtomicLong timestamp, AtomicLong counter, AtomicLong previousWindowSize, Executor executor) -
aggregateAndForward
private <R> void aggregateAndForward(BiFunction<Long, Collection<T>, R> f, AbstractPushStreamImpl<R> eventStream, PushEvent<? extends T> event, Queue<T> queue, Executor executor, long elapsed) -
adjustBackPressure
Description copied from interface:PushStream
Changes the back-pressure propagated by this pipeline stage.The supplied function receives the back pressure returned by the next pipeline stage and returns the back pressure that should be returned by this stage. This function will not be called if the previous pipeline stage returns negative back pressure.
- Specified by:
adjustBackPressure
in interfacePushStream<T>
- Parameters:
adjustment
-- Returns:
- Builder style (can be a new or the same object)
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adjustBackPressure
Description copied from interface:PushStream
Changes the back-pressure propagated by this pipeline stage.The supplied function receives the data object passed to the next pipeline stage and the back pressure that was returned by that stage when accepting it. The function returns the back pressure that should be returned by this stage. This function will not be called if the previous pipeline stage returns negative back pressure.
- Specified by:
adjustBackPressure
in interfacePushStream<T>
- Parameters:
adjustment
-- Returns:
- Builder style (can be a new or the same object)
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forEach
Description copied from interface:PushStream
Execute the action for each event received until the channel is closed. This is a terminating method, the returned promise is resolved when the channel closes.This is a terminal operation
- Specified by:
forEach
in interfacePushStream<T>
- Parameters:
action
- The action to perform- Returns:
- A promise that is resolved when the channel closes.
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toArray
Description copied from interface:PushStream
Collect the payloads in an Object array after the channel is closed. This is a terminating method, the returned promise is resolved when the channel is closed.This is a terminal operation
- Specified by:
toArray
in interfacePushStream<T>
- Returns:
- A promise that is resolved with all the payloads received over the channel
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toArray
Description copied from interface:PushStream
Collect the payloads in an Object array after the channel is closed. This is a terminating method, the returned promise is resolved when the channel is closed. The type of the array is handled by the caller using a generator function that gets the length of the desired array.This is a terminal operation
- Specified by:
toArray
in interfacePushStream<T>
- Parameters:
generator
-- Returns:
- A promise that is resolved with all the payloads received over the channel
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reduce
Description copied from interface:PushStream
Standard reduce, see Stream. The returned promise will be resolved when the channel closes.This is a terminal operation
- Specified by:
reduce
in interfacePushStream<T>
- Parameters:
identity
- The identity/begin valueaccumulator
- The accumulator- Returns:
- A
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reduce
Description copied from interface:PushStream
Standard reduce without identity, so the return is an Optional. The returned promise will be resolved when the channel closes.This is a terminal operation
- Specified by:
reduce
in interfacePushStream<T>
- Parameters:
accumulator
- The accumulator- Returns:
- an Optional
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reduce
public <U> Promise<U> reduce(U identity, BiFunction<U, ? super T, U> accumulator, BinaryOperator<U> combiner) Description copied from interface:PushStream
Standard reduce with identity, accumulator and combiner. The returned promise will be resolved when the channel closes.This is a terminal operation
- Specified by:
reduce
in interfacePushStream<T>
- Parameters:
identity
-accumulator
-combiner
- combines two U's into one U (for example, combine two lists)- Returns:
- The promise
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collect
Description copied from interface:PushStream
See Stream. Will resolve once the channel closes.This is a terminal operation
- Specified by:
collect
in interfacePushStream<T>
- Parameters:
collector
-- Returns:
- A Promise representing the collected results
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min
Description copied from interface:PushStream
See Stream. Will resolve onces the channel closes.This is a terminal operation
- Specified by:
min
in interfacePushStream<T>
- Parameters:
comparator
-- Returns:
- A Promise representing the minimum value, or null if no values are seen before the end of the stream
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max
Description copied from interface:PushStream
See Stream. Will resolve onces the channel closes.This is a terminal operation
- Specified by:
max
in interfacePushStream<T>
- Parameters:
comparator
-- Returns:
- A Promise representing the maximum value, or null if no values are seen before the end of the stream
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count
Description copied from interface:PushStream
See Stream. Will resolve onces the channel closes.This is a terminal operation
- Specified by:
count
in interfacePushStream<T>
- Returns:
- A Promise representing the number of values in the stream
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anyMatch
Description copied from interface:PushStream
Close the channel and resolve the promise with true when the predicate matches a payload. If the channel is closed before the predicate matches, the promise is resolved with false.This is a short circuiting terminal operation
- Specified by:
anyMatch
in interfacePushStream<T>
- Parameters:
predicate
-- Returns:
- A Promise that will resolve when an event matches the predicate, or the end of the stream is reached
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allMatch
Description copied from interface:PushStream
Closes the channel and resolve the promise with false when the predicate does not matches a pay load. If the channel is closed before, the promise is resolved with true.This is a short circuiting terminal operation
- Specified by:
allMatch
in interfacePushStream<T>
- Parameters:
predicate
-- Returns:
- A Promise that will resolve when an event fails to match the predicate, or the end of the stream is reached
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noneMatch
Description copied from interface:PushStream
Closes the channel and resolve the promise with false when the predicate matches any pay load. If the channel is closed before, the promise is resolved with true.This is a short circuiting terminal operation
- Specified by:
noneMatch
in interfacePushStream<T>
- Parameters:
predicate
-- Returns:
- A Promise that will resolve when an event matches the predicate, or the end of the stream is reached
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findFirst
Description copied from interface:PushStream
Close the channel and resolve the promise with the first element. If the channel is closed before, the Optional will have no value.- Specified by:
findFirst
in interfacePushStream<T>
- Returns:
- a promise
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findAny
Description copied from interface:PushStream
Close the channel and resolve the promise with the first element. If the channel is closed before, the Optional will have no value.This is a terminal operation
- Specified by:
findAny
in interfacePushStream<T>
- Returns:
- a promise
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forEachEvent
Description copied from interface:PushStream
Pass on each event to another consumer until the stream is closed.This is a terminal operation
- Specified by:
forEachEvent
in interfacePushStream<T>
- Parameters:
action
-- Returns:
- a promise
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