Class PubSub

  • public class PubSub
    extends java.lang.Object
    Sources and sinks to integrate Topic with streams allowing for local or distributed publishing and subscribing of elements through a stream.
    • Constructor Summary

      Constructor Description
    • Constructor Detail

      • PubSub

        public PubSub()
    • Method Detail

      • 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.

        topicActor - The actor ref for an 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.

        topicActor - The actor ref for an actor representing a specific topic.