a standard for asynchronous stream processing with non-blocking back pressure on the JVM
Reactive Streams is an initiative to provide a standard for asynchronous stream processing with non-blocking back pressure on the JVM.
Questions tagged [reactive-streams]
358 questions
6
votes
1 answer
How to download and process large data reactively?
I need to initiate download of some content over HTTP and then read the data as a reactive stream.
So, even though the downloaded data are big, I can almost immediately read the first few bytes of the response body (no need to wait for the whole…
Martin Heralecký
- 5,649
- 3
- 27
- 65
6
votes
2 answers
In spring boot webflux based microservice, who is the subscriber?
Note: Here the terms Subscriber and Subscription are being used from the reactive streams specification.
Consider the following @RestController methods in a spring boot webflux based microservice.
@GetMapping(path = "/users", produces =…
Jatin
- 667
- 8
- 16
6
votes
2 answers
Multiple sinks in the same stream
I have a stream like this and two sinks, but only one is used at a time:
Source.fromElements(1, 2, 3)
.via(flow)
.runWith(sink1)
or
Source.fromElements(1, 2, 3)
.via(flow)
.runWith(sink2)
It is configurable which sink we use, but what if I have…
Piotr Kozlowski
- 899
- 1
- 13
- 25
6
votes
2 answers
Java 9 Behavior of Flow SubmissionPublisher offer method
I´ve been playing with Java Flow offer operator but after read the documentation and do my test I dont understand.
Here my test
@Test
public void offer() throws InterruptedException {
//Create Publisher for expected items Strings
…
paul
- 12,873
- 23
- 91
- 153
6
votes
1 answer
Akka Streams split stream by type
I have the following simple case class hierarchy:
sealed trait Message
case class Foo(bar: Int) extends Message
case class Baz(qux: String) extends Message
And I have a Flow[Message, Message, NotUsed] (from a Websocket-based protocol with codec…
Alexander Temerev
- 2,654
- 3
- 27
- 34
6
votes
1 answer
Creating a Source out of an EventStream
I am using PlayFramework 2.5.3 and would like to create an akka.stream.scaladsl.Source from an akka.event.EventStream (the eventstream is part of an actor system). The event stream would produce events from a certain type, so I would need to…
Alexander Weber
- 789
- 4
- 16
6
votes
2 answers
Scala Slick: Never ending stream
With Slick you can do the following to produce a stream of results from a table:
val q = for (e <- events) yield e.name
val p: DatabasePublisher[String] = db.stream(q.result)
p.foreach { s => println(s"Event: $s") }
That will print all the events…
David
- 1,862
- 2
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- 35
6
votes
1 answer
spring integration vs reactive-streams
I'm working on an ETL project. I've been using spring integration for a long time. The data source is currently files or chronicle but it may change to live streams and volumes are likely to grow. There is a potential to move on to big data…
fitifiti
- 97
- 6
6
votes
1 answer
How to merge two streams (without nulls) and apply conditions on pairs?
Consider I have two streams of data, is there a way to merge them and apply conditions on data between these two streams? For example
Stream A : A, B, C, D....
Stream B : -, A, -, -....
Composed : (A,-),(B,A),(C,-),(D,-)....
How to get composed…
opensourcegeek
- 5,552
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5
votes
2 answers
publishOn vs subscribeOn when making a blocking call in Reactor
In the blog post Flight of the Flux 3, the authors suggest wrapping a synchronous blocking call in a Mono with a subscribeOn call, as shown in this snippet from the article:
final Flux betterFetchUrls(List urls) {
return…
kousen
- 2,897
- 3
- 28
- 26
5
votes
0 answers
How to mock FindPublisher in reactive mongo driver
I'm writing an application using mongo reactive driver and reactivestreams library in Java.
I have the following DAO code:
@Override
public Flux findBySearch(String appKey, ContentVersionSearchRequest request, Pager pager) {
…
sedran
- 3,498
- 3
- 23
- 39
5
votes
1 answer
What is the difference between Schedulers.newElastic and Schedulers.elastic methods?
I am working on Flux and Mono and using them in multi threaded environment and using the Schedular which provide the worker thread.
There are many options to start the Schedular using elastic, parallel and newElastic.
Here is the code which i used:
…
KayV
- 12,987
- 11
- 98
- 148
5
votes
2 answers
How to convert cold stream into hot stream in Project Reactor 3?
As per the definition of Mono and Flux, both represent an asynchronous sequence of data, and nothing happens before you subscribe.
And there are two broad families of publishers: hot and cold.
Mono and Flux generate data anew for each subscription.…
KayV
- 12,987
- 11
- 98
- 148
5
votes
1 answer
Asynchronous, composable return value for vector/stream data in Java 9
Say I have an API that, based on some query criteria, will find or construct a widget:
Widget getMatchingWidget(WidgetCriteria c) throws Throwable
The (synchronous) client code looks like:
try {
Widget w = getMatchingWidget(criteria);
…
David Moles
- 48,006
- 27
- 136
- 235
5
votes
2 answers
How to correctly wrap a Flux inside a Mono object
I have a web-service which returns student and enrolled class details.
{
"name": "student-name",
"classes": [
{
"className": "reactor-101",
"day": "Tuesday"
},
{
"className": "reactor-102",
"day": "Friday"
…
K. Bhandari
- 53
- 1
- 4