Package org.apache.pekko.stream.typed.javadsl

Class PubSub

java.lang.Object

org.apache.pekko.stream.typed.javadsl.PubSub

public class PubSub
extends Object

Sources and sinks to integrate pekko.actor.typed.pubsub.Topic with streams allowing for local or distributed publishing and subscribing of elements through a stream.

Constructor Summary

Constructors

Constructor	Description
PubSub()

Method Summary

Modifier and Type	Method	Description
static <T> Sink<T,NotUsed>	sink(ActorRef<Topic.Command<T>> topicActor)	Create a sink that will publish each message to the given topic.
static <T> Source<T,NotUsed>	source(ActorRef<Topic.Command<T>> topicActor, int bufferSize, OverflowStrategy overflowStrategy)	Create a source that will subscribe to a topic and stream messages published to the topic.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

PubSub

public PubSub()

Method Details

source

public static <T> Source<T,NotUsed> source(ActorRef<Topic.Command<T>> topicActor,
 int bufferSize,
 OverflowStrategy overflowStrategy)

Create a source that will subscribe to a topic and stream messages published to the topic. Can be materialized multiple times, each materialized stream will contain messages published after it was started.

Note that it is not possible to propagate the backpressure from the running stream to the pub sub topic, if the stream is backpressuring published messages are buffered up to a limit and if the limit is hit the configurable OverflowStrategy decides what happens. It is not possible to use the Backpressure strategy.

Parameters:

topicActor - The actor ref for an org.apache.pekko.actor.typed.pubsub.Topic actor representing a specific topic.

bufferSize - The maximum number of messages to buffer if the stream applies backpressure

overflowStrategy - Strategy to use once the buffer is full.

sink

public static <T> Sink<T,NotUsed> sink(ActorRef<Topic.Command<T>> topicActor)

Create a sink that will publish each message to the given topic. Note that there is no backpressure from the topic, so care must be taken to not publish messages at a higher rate than that can be handled by subscribers. If the topic does not have any subscribers when a message is published the message is sent to dead letters.

Parameters:

topicActor - The actor ref for an org.apache.pekko.actor.typed.pubsub.Topic actor representing a specific topic.