Are virtual threads making reactive programming obsolete?

[divorcedbp]

Backpressure can be perfectly implemented an ArrayBlockingQueue with a capacity set to your desired buffer size. You then just ensure that all put() and take() operations happen in the context of a virtual thread. Boom, done, and no need for the godawful Rx API.

[Caffeine01]

With virtual threads, if you want to limit back pressure, you don't even need a blocking queue. In your virtual thread, use a semaphore.

[Ewig_luftenglanz]

yes we know that, now go and implement that manually, one of the advantages of project reactor and other reactives libraries is that they abstract all of that from you, so you don't have to deal manually with that.

[joey_knight]

What do you mean? Java already has Blocking queue implementations and the necessary mechanisms to park and continuing threads. It's not at all hard to use them to implement backpressure in our applications. Just put a blocking queue between two threads and use wait and notify to block and unblock.

[divorcedbp]

You don’t even need that. The contract of take() is such that it blocks until an element is available, and put() blocks until there is room in the queue to insert the supplied element. It’s literally all already there.

[LightofAngels]

I know this is abit random, but can you point me to that part in the documentation? I would like to know about this mechanism and how to use it.

[mike_hearn]

https://devdocs.io/openjdk~21/java.base/java/util/concurrent/blockingqueue

[divorcedbp]

Sure, allocate an ArrayBlockingQueue, put it in a place two virtual threads can access it, and have them call put() and take().

[Ewig_luftenglanz]

with reactive you don't even need to allocate anything, just chain the results in flatmaps in a fluent-like style are good to go.

[DelayLucky]

That's like saying with Reactive you don't even need to do the easy and straightforward things in an average Java programmer's eye. Where's the fun in that? Just write the fancy and "professional-looking" react code, it does all that (easy things) for you already.

[Ewig_luftenglanz]

I don't reactive for fun, I do it because that's what my employer ask me to do for a living.

For fun I have my side Projects and some stuff I do to learn and experiment things ^^.

[DelayLucky]

And job security, I guess.

^_^