Im just starting out with coroutines, so this may ...

# getting-started

[F0X]

Im just starting out with coroutines, so this may be a weird question. Is it possible and how would I go about implementing a MainCoroutineDispatcher that simply runs the coroutines on an existing main thread?

[F0X]

That is what I mean, I want to register my own Main dispatcher to use one existing, plain java thread. I am not working in an environment where this already exists, like Android, Swing or JavaFX

[F0X]

Look I don't think you understand, Dispatchers.Main does not exist without someone registering the appropriate service, which is what I want to do.
Because I am integrating this code into an existing Program as a kind of "Plugin" I want to create a simple Dispatcher that runs all coroutines on this single existing thread.

[Chrimaeon]

you can convert an Executor to a dispatcher. https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutine[…]/java.util.concurrent.-executor/as-coroutine-dispatcher.html

[Dominaezzz]

I think what you're looking for is runBlocking which creates a dispatcher on the calling thread for the coroutines to run.
If you're looking to create a dispatcher object, I think that can be done in a useful way since the dispatcher has to take control of the thread by blocking it.

[F0X]

Turned out the underlying program already chose to have their own Executor for running things on the main thread, so I could just do as @Chrimaeon suggested and delegate to this.
Even though it seems a bit hacky using this "InternalCoroutinesApi" to set Dispatchers.Main myself everything is working fine so far.
Thank you all for helping out!