what s a good way to do things concurrently in `init `

Question

Dominaezzz · Answer

`runBlocking launch task `

vineethraj49 · Answer

this for some reason got stuck when instantiated from within a Dispatchers Default

gildor · Answer

Not the best pattern to have blocking code in init better to provide asyncronous builder function for it

gildor · Answer

do you have reproduction sample when it stuck

vineethraj49 · Answer

no confused I just moved it all to `CompletableFuture` and ` join` and moved on will try to figure out where it got stuck when I get around to it again

gildor · Answer

why do you need CompletableFuture with coroutines At least for this case

vineethraj49 · Answer

I don t wanted to know if there s a standard way to do concurrency in init given my `runBlocking` attempt got stuck

gildor · Answer

Those are 2 different problems

gildor · Answer

stucked runBlocking probably means that your code inside has some deadlock hard to say without sample but most probably just some bug in your implementations

gildor · Answer

second problem how to do something concurrent in init you can do that as Dominic suggest if you want make it blocking so object cannot be created until operation is finished But imo it s very bad pattern object creation shouldn t block for long time

gildor · Answer

if create object before operation is finished is fine just launch a coroutine from init no need to use runBlocking I would also probably avoid it harder to test and adds background tasks but better then blocking

gildor · Answer

if you still want to create object only when all you operations are finished I would recommend use factory method even better if it suspend which does all operations asyncronously in parallel and create object after that and return instance of it It also work well with private constructor and invoke operator in companion object so it allows you make almost real suspend constructor

Orhan Tozan · Answer

`suspend init `

gildor · Answer

I don t think that I buy it opens all kind compatibility issues with Java and all other platforms Also init block is not a part of public API or signature but adding suspending init means that class constructor also become suspending so it will break all non suspend clients

jdemeulenaere · Answer

I would suggest to create a `suspend` factory method on the companion object that does all the concurrent stuff needed to initialize your object e g ```class MyClass val param1 String val param2 String companion object suspend operator fun invoke MyClass return coroutineScope val param1 = async val param2 = async MyClass param1 await param2 await ```

jdemeulenaere · Answer

Oops sorry < gildor> just saw you suggested the same slightly smiling face