Hi Pavel,
your suggestion to use Java 9 Flow API sounds good. Flow looks good to me.
Regarding the idea of "Adapter" classes for Java 9 support -- it is a pragmatic approach.
Are you actually implementing a PoC in parallel with the API? Does the current Jersey "master" branch already reflect your API proposals?
cheers,
adam
> On 24 Jan 2017, at 20:54, Pavel Bucek <pavel.bucek_at_oracle.com> wrote:
>
> Dear experts,
>
> please allow me to bring up another addition planned to be included in JAX-RS 2.1: Support for Server Sent Events.
>
> The API was introduced a while back [1], but we did incorporate some changes, mostly alignments with Java SE 8 and another one, slightly more controversial - alignment with Java SE 9 Flow API.
>
> Why we should use Flow API? We want to make the transition to Java 9 as smooth as possible. Please note that today, the JAX-RS sources do contain Flow class (1:1 copy from Java SE 9), but that is NOT a final state. We want to work with it as much as possible, but we will minimize and clean up the code before final release. How? Consider following example:
>
> public interface SseBroadcaster extends
> AutoCloseable, Flow.Publisher<OutboundSseEvent> {
>
> //...
>
> }
>
> could be modified to
>
> public interface SseBroadcaster extends
> AutoCloseable {
>
> //...
> void subscribe(SseSubscriber<? super
> OutboundSseEvent> subscriber);
> }
>
> I hope you will like the attempt to be "forward-compatible", but I assume that this proposal alone will bring some opinions - please share them! Last note: currently, the Flow API is used only in SSE. We plan to use it heavily in Non-blocking I/O. If you think there are other areas where we can take advantage of Subscriber/Publisher methods, please let us know.
> Let me get back to the SSE API.
>
> Very brief description of the API is on the wiki [2], I will expand that once we'll have some feedback.
> The proposal contains support for server and client side. All classes are in the package javax.ws.rs.sse [3]. There is no added class from the last proposal, but there are some changes:
>
> - [server] SseBroadcaster extends Publisher<OutboundSseEvent>
> - [server] replaced SseBroadcaster.Listener by SseBroadcaster#onException and SseBroadcaster#onClose
> - [server] SseEventOutput extends Subscriber<OutboundSseEvent>
> - [client] SseEventSource extends Publisher<InboundSseEvent>
> Corresponding commit [4] looks like a bigger one, but most of it is renaming based on introduced interfaces, the core of the change is relatively small.
>
> I look forward to your comments and suggestions.
> I don't want to prolong this already too long email - please let me know if there are some areas which I should describe in more detail.
>
> Thanks and regards,
> Pavel & Santiago
> [1] https://java.net/projects/jax-rs-spec/lists/jsr370-experts/archive/2015-10/message/28
> [2] https://java.net/projects/jax-rs-spec/pages/ServerSentEvents
> [3] https://github.com/jax-rs/api/tree/master/jaxrs-api/src/main/java/javax/ws/rs/sse
> [4] https://github.com/jax-rs/api/commit/b2b8f3f4f20696558a3ff52b0de17fb04c343d02