what am I supposed to use instead of actor if I need an acto

Question

what am I supposed to use instead of actor if I need an actor

Casey Brooks · Answer

The deprecated `actor ` function is little more than a `Channel` so that could be the basis for your own implementation of an Actor pattern

fitermay · Answer

why would I prefer to implement my own over a library implementation The chances that my own implementation will be superior to even a deprecated one is small

fitermay · Answer

sure it s simple to get a simple one that works but I don t know all the edge cases

Casey Brooks · Answer

that s basically why it s still there There is no official replacement within the core coroutines library but the current actor API really doesn t offer much outside of a standard Channel and some basic guidance for how to use actors and the `actor` API itself wasn t really designed to handle all the use cases of Actors properly either There s been an open issue to create a robust actor framework for many years but it s basically on hold indefinitely So some folks do choose to keep using the `actor` function because it s been said that it s not going to get removed until if a proper replacement does come But at the same time since there s so little to those APIs its easy enough that you may want to create your own set of APIs based around Channels to future proof yourself in the case that it does get removed eventually

ephemient · Answer

the issue btw <https github com Kotlin kotlinx coroutines issues 87>

ephemient · Answer

setting up a channel + launching a <https kotlinlang org api kotlinx coroutines kotlinx coroutines core kotlinx coroutines channels consume html|ReceiveChannel consume> is pretty much the same as what `actor ` used to give you there wasn t anything magic there

Casey Brooks · Answer

Or alternatively actors are just one mechanism for managing concurrent work Depending on your needs other patterns like MVI be a suitable alternative Actors are primarily concerned with moving data asynchronously through a series of stages but you may be more interested in the aspect of queueing to ensure atomic updates to some shared variable MVI can be a great pattern in this case and there are several libraries available to help with MVI state management is a library I maintain but there are with different DSLs that you may find more to your liking

Casey Brooks · Answer

And just to demonstrate how little there is to the `actor` function this is pretty much all you d need for a full replacement of that function Again there s nothing magic here ```public fun lt T gt CoroutineScope actor block suspend ReceiveChannel lt T gt gt Unit SendChannel lt T gt val channel = Channel lt T gt Channel RENDEZVOUS launch block channel return channel ```

ephemient · Answer

that doesn t handle cancellation the way that `actor ` or `consume ` do but conceptually it s there

ephemient · Answer

this would be closer to how the deprecated `actor ` behaves since `consume ` also cancels the channel when the block completes or is cancelled ```fun lt E gt CoroutineScope actor context CoroutineContext = EmptyCoroutineContext capacity Int = 0 start CoroutineStart = CoroutineStart DEFAULT onCompletion CompletionHandler = null block suspend ReceiveChannel lt E gt gt Unit SendChannel lt E gt val channel = Channel lt E gt capacity val job = launch context start channel consume block if onCompletion = null job invokeOnCompletion onCompletion return channel ``` although it doesn t handle `start = CoroutineStart LAZY` and the original implementation does

ephemient · Answer

still no magic