Channel Synchronization in ActionScript

Our example demonstrates how to synchronize execution across different threads in ActionScript. We’ll use an event to notify when a worker function has completed its task. This is similar to using channels for synchronization in other languages.

package {
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.utils.setTimeout;

    public class ChannelSynchronization extends Sprite {
        public function ChannelSynchronization() {
            worker(onWorkerComplete);
        }

        private function worker(callback:Function):void {
            trace("working...");
            // Simulate work with a timeout
            setTimeout(function():void {
                trace("done");
                callback();
            }, 1000);
        }

        private function onWorkerComplete():void {
            trace("Worker has completed");
        }
    }
}

This is the worker function we’ll run in a separate “thread” (note that ActionScript doesn’t have true multithreading, but we can simulate asynchronous behavior). The callback function will be used to notify when this function’s work is done.

In the worker function:

private function worker(callback:Function):void {
    trace("working...");
    // Simulate work with a timeout
    setTimeout(function():void {
        trace("done");
        callback();
    }, 1000);
}

We start the worker function and provide a callback to be notified when it’s done:

worker(onWorkerComplete);

The onWorkerComplete function is called when the worker has finished:

private function onWorkerComplete():void {
    trace("Worker has completed");
}

When you run this ActionScript code, you should see output similar to:

working...
done
Worker has completed

If you removed the callback() call from the worker function, the program would finish without waiting for the worker to complete its task.

In ActionScript, we use callbacks and events for asynchronous programming, as it doesn’t have built-in constructs for concurrent programming like some other languages do. This approach allows us to achieve similar functionality in terms of synchronizing different parts of our code.