users@jax-rs-spec.java.net

[jax-rs-spec users] Re: Server-Sent Events API proposal

From: Santiago Pericasgeertsen <santiago.pericasgeertsen_at_oracle.com>
Date: Mon, 30 Jan 2017 10:39:22 -0500

Hi Sebastian,

 Are your re-written examples publicly available? If so, could you share them with the group?

 Thanks.

— Santiago

> On Jan 28, 2017, at 5:49 AM, Sebastian Daschner <java_at_sebastian-daschner.de> wrote:
>
> Hi Pavel,
>
> some feedback -- after rewriting my examples I did for the Java Magazine article last year:
>
> I like the change on the SseBroadcaster, it makes the code leaner.
>
> The new Subscriber model on the client side is IMO more cumbersome to use. The examples declare their own AbstractSubscriber, even if they're just interested in #onNext. Visible when you look at the changes of SseClient in b2b8f3f. IMO we should a least provide shortcuts to the client.
>
> Cheers,
> Sebastian
>
>
> On 01/24/2017 08:54 PM, Pavel Bucek 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 <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 <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 <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 <https://github.com/jax-rs/api/commit/b2b8f3f4f20696558a3ff52b0de17fb04c343d02>
>