[SOLVED] Does kotlin coroutines have async call with timer?

Does kotlin coroutines have async call with timer?

Does Kotlin has possibility to call function async() in coroutines with some time, witch will return default result after time completion?

I found that it's possible to only call await, and than infinity wait the result.

async {
        ...
        val result = computation.await()
        ...
}

But real production case than you need to return either default result or exception. What is proper way to do something in Kotlin coroutines? Like something similar to this:

async {
        ...
        val timeout = 100500
        val result: SomeDeferredClass = computation.await(timeout)
        if (result.isTimeout()) {
           // get default value
        } else {
           // process result
        }
        ...
}

Solution

You can use the withTimeout-function. It will throw a CancellationException when it times out. You could catch this exception and return your default value.

Something like this:

async {
    ...
    val timeout = 100500L

    try {
        withTimeout(timeout) {
            computation.await()
        }
        ...
    } catch (ex: CancellationException) {
        defaultValue
    }
}

You could also use the withTimeoutOrNull-function, which returns null on timeout. Like this:

async {
    ...
    val timeout = 100500L
    withTimeoutOrNull(timeout) { computation.await() } ?: defaultValue
}

This approach won't let you differentiate between a timeout and a computation that returns null though. The default value would be returned in both cases.

For more info, see here: https://github.com/Kotlin/kotlinx.coroutines/blob/master/coroutines-guide.md#timeout