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#18021 Sink.seq and FlowOps.limit and .limitWeighted

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lolski 2015-11-19 00:11:07 +08:00 • committed by Roland Kuhn
parent 52655f2836
commit aadaf15b89
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52
akka-stream/src/main/scala/akka/stream/javadsl/SubSource.scala
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@ -278,6 +278,58 @@ class SubSource[+Out, +Mat](delegate: scaladsl.SubFlow[Out, Mat, scaladsl.Source
*
* '''Cancels when''' downstream cancels
*/
/**
* Ensure stream boundedness by limiting the number of elements from upstream.
* If the number of incoming elements exceeds max, it will signal
* upstream failure `StreamLimitException` downstream.
*
* Due to input buffering some elements may have been
* requested from upstream publishers that will then not be processed downstream
* of this step.
*
* The stream will be completed without producing any elements if `n` is zero
* or negative.
*
* '''Emits when''' the specified number of elements to take has not yet been reached
*
* '''Backpressures when''' downstream backpressures
*
* '''Completes when''' the defined number of elements has been taken or upstream completes
*
* '''Cancels when''' the defined number of elements has been taken or downstream cancels
*
* See also [[Flow.take]], [[Flow.takeWithin]], [[Flow.takeWhile]]
*/
def limit(n: Int): javadsl.SubSource[Out, Mat] = new SubSource(delegate.limit(n))
/**
* Ensure stream boundedness by evaluating the cost of incoming elements
* using a cost function. Exactly how many elements will be allowed to travel downstream depends on the
* evaluated cost of each element. If the accumulated cost exceeds max, it will signal
* upstream failure `StreamLimitException` downstream.
*
* Due to input buffering some elements may have been
* requested from upstream publishers that will then not be processed downstream
* of this step.
*
* The stream will be completed without producing any elements if `n` is zero
* or negative.
*
* '''Emits when''' the specified number of elements to take has not yet been reached
*
* '''Backpressures when''' downstream backpressures
*
* '''Completes when''' the defined number of elements has been taken or upstream completes
*
* '''Cancels when''' the defined number of elements has been taken or downstream cancels
*
* See also [[Flow.take]], [[Flow.takeWithin]], [[Flow.takeWhile]]
*/
def limitWeighted(n: Long)(costFn: function.Function[Out, Long]): javadsl.SubSource[Out, Mat] = {
new SubSource(delegate.limitWeighted(n)(costFn.apply))
}
def sliding(n: Int, step: Int = 1): SubSource[java.util.List[Out @uncheckedVariance], Mat] =
new SubSource(delegate.sliding(n, step).map(_.asJava)) // TODO optimize to one step