How do I create a `Scheduler` for `observeOn` method?

Question

I'm using RxJava in my Scala project and I need to execute my Observable in a separate thread. I know in order to achieve this I need to call observeOn method on it and pass an instance of rx.lang.scala.Scheduler as an argument.

But how can I create that instance? I did not find any apparent ways of instantiating of rx.lang.scala.Scheduler trait. For example, I have this code:

Observable.from(List(1,2,3)).observeOn(scheduler)

Can someone provide an example of working scheduler variable that will do the trick?

Answer 1

A trait is not instantiable.

You need to use one of the subclasses of the trait listed under "Known Subclasses" in the API documentation.

Answer 2

All schedulers are in the package

import rx.lang.scala.schedulers._

For blocking IO operations, use IO scheduler

Observable.from(List(1,2,3)).observeOn(IOScheduler())

For computational work, use computation scheduler

Observable.from(List(1,2,3)).observeOn(ComputationScheduler())

To execute on the current thread

Observable.from(List(1,2,3)).observeOn(ImmediateScheduler())

To execute on a new thread

Observable.from(List(1,2,3)).observeOn(NewThreadScheduler())

To queues work on the current thread to be executed after the current one

Observable.from(List(1,2,3)).observeOn(TrampolineScheduler())

If you want to use your own custom thread pool

val threadPoolExecutor = Executors.newFixedThreadPool(2)
val executionContext = ExecutionContext.fromExecutor(threadPoolExecutor)
val customScheduler = ExecutionContextScheduler(executionContext)
Observable.from(List(1,2,3)).observeOn(customScheduler)