RestAction should implement Publisher

Issue

Issue Type

• Bug Report
• Feature Request

Description

I have been using Project Reactor for a few months now. Libraries like these make it easy to work with async operations in a functional way. Lately, I figured that JDA’s RestAction can be adapted to fit into this API by implementing Publisher.

A Publisher’s action will only start once it has been subscribed to (similar to rest actions). Multiple subscribers may be added. Subscribers are like event handlers, and handle these 4 events:

• onSubscribe(Subscription)
• onNext(T)
• onError(Throwable)
• onComplete()

The problem with this is that the flow API was introduced in Java 9. I am not sure if the JVM allows us to implement an interface which is not loaded (say when running JRE 8).

Documentation:

• https://docs.oracle.com/javase/10/docs/api/java/util/concurrent/Flow.Publisher.html
• https://docs.oracle.com/javase/10/docs/api/java/util/concurrent/Flow.Subscriber.html
• https://docs.oracle.com/javase/10/docs/api/java/util/concurrent/Flow.Subscription.html

[kantenkugel]

As we are building against java8, this will probably not work then.

And we will very likely stay on 8 for a while (compatibility) and then sometime in the future switch to Java 11. At that point we can consider adding the stuff described in the issue, but currently it won’t work i guess.

[MinnDevelopment]

The reason we do not want to update is backward compatibility. Considering that we don’t gain a lot of bumping the version while we bring an inconvenience to the userbase is a big influence on the decision that we want to stay java 8 compatible for now.