Package jakarta.ws.rs.sse

Interface SseEventSink

All Superinterfaces:
AutoCloseable
public interface SseEventSink
extends AutoCloseable
Outbound Server-Sent Events stream.

The instance of SseEventSink can be only acquired by injection of a resource method parameter: 

 @GET
 @Path("eventStream")
 @Produces(MediaType.SERVER_SENT_EVENTS)
 public void eventStream(@Context SseEventSink eventSink) {
     // ...
 }
The injected instance is then considered as a return type, so the resource method doesn't return anything, similarly as in server-side async processing.

The underlying client connection is kept open and the application code is able to send events. A server-side instance implementing the interface corresponds exactly to a single client HTTP connection.

The injected instance is thread safe.

Since:
2.1
Author:
Marek Potociar (marek.potociar at oracle.com)

  • Method Summary

    Modifier and Type Method Description
    void close()
    Close the SseEventSink instance and release all associated resources.
    boolean isClosed()
    Check if the stream has been closed already.
    CompletionStage<?> send​(OutboundSseEvent event)
    Send an outbound Server-sent event to this sink.

  • Method Details

    • isClosed

      boolean isClosed()
      Check if the stream has been closed already.

      Please note that the client connection represented by this SseServerSink can be closed by the client side when a client decides to close connection and disconnect from the server.

      Returns:
      true when closed, false otherwise.

    • send

      CompletionStage<?> send​(OutboundSseEvent event)
      Send an outbound Server-sent event to this sink.

      Event will be serialized and sent to the client.

      Parameters:
      event - event to be written.
      Returns:
      completion stage that completes when the event has been sent. If there is a problem during sending of an event, completion stage will be completed exceptionally.

    • close

      void close()
      Close the SseEventSink instance and release all associated resources.

      Subsequent calls have no effect and are ignored. Once the SseEventSink is closed, invoking any method other than this one and isClosed() would result in an IllegalStateException being thrown.

      Specified by:
      close in interface AutoCloseable