[generics] hello :wave: Is there a nice way to avo...

# announcements

[Dariusz Kuc]

[generics] hello 👋
Is there a nice way to avoid the extra cast below?

fun <T : AbstractStub<*>> getClient(stubFactory: (Channel) -> T): T {
    val client = stubFactory.invoke(configuredChannel)
    return if (deadlineMs != null) {
        // returns AbstractStub<S>
        client.withDeadlineAfter(deadlineMs, TimeUnit.MILLISECONDS) as T
    } else {
        client
    }
}

was playing around with inlining the T but cannot get it to work
---
doing the chaining call from from the caller works as expected

val client: HelloGrpc.HelloBlockingStub = getClient { HelloGrpc.newBlockingStub(it) }.withDeadlineAfter(1000, TimeUnit.MILLISECONDS)

[Joe]

does it work if you change the generic signature to fun <T : AbstractStub<T>> getClient(stubFactory: () -> T): T { ? That should make it an AbstractStub<T> instead of an AbstractStub<S>

[Dariusz Kuc]

doh

[Dariusz Kuc]

indeed

[Dariusz Kuc]

thanks!

[asad.awadia]

Why have this function at all?

[Dariusz Kuc]

that function is within a channel factory that automatically configures the underlying channel based on the properties

[Dariusz Kuc]

i got some standard enterprise configs that i need to apply on the underlying channel (e.g. tracing, metrics, circuit breakers, etc) so it was just a convenient way of creating clients using the configured channel

[Dariusz Kuc]

technically could expose the channel as a bean and have it consumed directly

[Dariusz Kuc]

might look into this