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=str #19423 add satefulMapConcat

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This commit is contained in:
Alexander Golubev 2016-01-27 00:00:39 -05:00
parent 3d9ea4415f
commit 2a36859578
11 changed files with 347 additions and 80 deletions
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36
akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
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@ -779,6 +779,7 @@ final class Source[+Out, +Mat](delegate: scaladsl.Source[Out, Mat]) extends Grap
* RecoverWith allows to switch to alternative Source on flow failure. It will stay in effect after
* a failure has been recovered so that each time there is a failure it is fed into the `pf` and a new
* Source may be materialized.
*
* Since the underlying failure signal onError arrives out-of-band, it might jump over existing elements.
* This stage can recover the failure signal, but not the skipped elements, which will be dropped.
*
@ -796,7 +797,7 @@ final class Source[+Out, +Mat](delegate: scaladsl.Source[Out, Mat]) extends Grap
new Source(delegate.recoverWith(pf))
/**
* Transform each input element into an `Iterable of output elements that is
* Transform each input element into an `Iterable` of output elements that is
* then flattened into the output stream.
*
* Make sure that the `Iterable` is immutable or at least not modified after
@ -817,7 +818,38 @@ final class Source[+Out, +Mat](delegate: scaladsl.Source[Out, Mat]) extends Grap
* '''Cancels when''' downstream cancels
*/
def mapConcat[T](f: function.Function[Out, _ <: java.lang.Iterable[T]]): javadsl.Source[T, Mat] =
new Source(delegate.mapConcat(elem ⇒ Util.immutableSeq(f.apply(elem))))
new Source(delegate.statefulMapConcat(() ⇒ elem ⇒ Util.immutableSeq(f.apply(elem))))
/**
* Transform each input element into an `Iterable` of output elements that is
* then flattened into the output stream. The transformation is meant to be stateful,
* which is enabled by creating the transformation function anew for every materialization —
* the returned function will typically close over mutable objects to store state between
* invocations. For the stateless variant see [[#mapConcat]].
*
* Make sure that the `Iterable` is immutable or at least not modified after
* being used as an output sequence. Otherwise the stream may fail with
* `ConcurrentModificationException` or other more subtle errors may occur.
*
* The returned `Iterable` MUST NOT contain `null` values,
* as they are illegal as stream elements - according to the Reactive Streams specification.
*
* '''Emits when''' the mapping function returns an element or there are still remaining elements
* from the previously calculated collection
*
* '''Backpressures when''' downstream backpressures or there are still remaining elements from the
* previously calculated collection
*
* '''Completes when''' upstream completes and all remaining elements has been emitted
*
* '''Cancels when''' downstream cancels
*/
def statefulMapConcat[T](f: function.Creator[function.Function[Out, java.lang.Iterable[T]]]): javadsl.Source[T, Mat] =
new Source(delegate.statefulMapConcat{ () ⇒ {
val fun = f.create()
elem ⇒ Util.immutableSeq(fun(elem))
}})
/**
* Transform this stream by applying the given function to each of the elements