good day everyone. got a coroutine question. I wan...

# getting-started

[Oleg Shuliak]

good day everyone.
got a coroutine question. I want to set the property value for each object in the list by calling the suspension function and setting the result:

coroutineScope {
            workflows.forEach {
                it.status = formWorkflowActivationStateManager.getCurrentState(it, companyId).toWorkflowStatus()
            }
        }

I’m wondering if the coroutineScope is enough to parallel those executions or if I need to use async/await?

[Sam]

Yes, you need to use async — coroutines are sequential by default

[Oleg Shuliak]

thanks @Sam
but could you give me a hint on how to implement that for each entity in a list?

[Sam]

Wrong Sam 😉

[Sam]

In your example, since you don’t need to return a result from the parallel tasks, you can just use launch, like:

coroutineScope {
    workflows.forEach {
        launch { it.status = ... }
    }
}

The coroutineScope will wait for all the launched tasks to finish before returning.

[Oleg Shuliak]

sorry @Sam my bad 😄

[Oleg Shuliak]

and launch will create a parallel task for each entity, right?

[Sam]

Yes 👍

[Youssef Shoaib [MOD]]

Indeed it will. The equivalent if you wanted a result out of each would be to do

coroutineScope {
  workflows.map { async { it.status = ... } }.awaitAll()
}

Keep in mind that this and launch will cancel all operations eventually if one fails. If that's not what you want, you can do supervisorScope instead of coroutineScope

[Oleg Shuliak]

prefect, thanks everyone for help!