Does anybody have a project with a guava event bus on it and

Question

Does anybody have a project with a guava event bus on it and suspending async ing subscribers I would very much like to have ` guava Subscribe suspend fun handle event MyEvent ` functions but by default guava has no idea how to handle that I ve tried 1 switching my tests to invoke handlers directly This works for tests but has trouble with some of our components 2 adding an obnoxious inheritance system to try and keep a `List lt Job gt ` on the event itself that gets appended to by subscribers This is not great I d be willing to take a fork of evenBus just for support for concurrent amp synchronous event publication especially if I can get it without retrofitting existing blocking java code

groostav · Answer

bump This is getting me I ve got a large project in java using the guava event bus and not being able to `suspend` across `<http eventBus post|eventBus post> ` calls is making things very difficult

Evan R. · Answer

What s the purpose of making the `handle ` function a suspend function Is it called by other things or are you trying to get it to be handled in some coroutine context

Evan R. · Answer

i e are you trying to make the handling of an event not block the bus

groostav · Answer

a summary of my problem we post events when things change Sometimes that kicks off autosave a big suspending IO operation Right now we dot hat operation asynchronously and with bugs It would be simpler if I could have the autosave operation be a `suspend` read synchronous amp concurrent operation but to do that it needs to back pressure the caller of `post` by `suspend` ing it

groostav · Answer

it strikes me that an extension function on `EventBus` and inheritence on events sigh is still the best way to go

Evan R. · Answer

Either way you ll need to end up blocking a thread unless you want to rewrite EventBus to be suspending from the ground up It s asynchronous under the hood using java Executor based on what I ve seen on github

Evan R. · Answer

If order doesn t matter you might be able to spin up your own thread pool and convert it to a coroutine dispatcher then toss autoSave calls into the pool via launch

Evan R. · Answer

If order does matter you ll need to block the subscriber s thread via a buffered channel with sendBlocking

Evan R. · Answer

Then just toss some coroutine workers into the thread pool