/// <summary>
/// Create a new <see cref="IObservable{T}">observable</see> that forwards messages from an <see cref="ActorEventBus{TEvent,TClassifier}">actor-based event bus</see> subscription to subscribed <see cref="IObserver{T}">observer</see>s.
/// </summary>
/// <typeparam name="TEventMessage">
/// The base message type used to represent events from the bus.
/// </typeparam>
/// <typeparam name="TEventClassifier">
/// The type used to classify events on the bus (i.e. select the "channel" or "audience" for which a given event is intented).
/// </typeparam>
/// <param name="eventBus">
/// The actor-based event bus.
/// </param>
/// <param name="system">
/// The actor system that will host the subscribing actor (usually, this is the actor system that hosts the event bus).
/// </param>
/// <param name="subscriptionClassifier">
/// The classifier value that is passed to the event bus when subscribing.
/// </param>
/// <returns>
/// The <see cref="IObservable{T}">observable</see>.
/// </returns>
public static IObservable <TEventMessage> ToObservable <TEventMessage, TEventClassifier>(this ActorEventBus <TEventMessage, TEventClassifier> eventBus, ActorSystem system, TEventClassifier subscriptionClassifier)
{
if (eventBus == null)
{
throw new ArgumentNullException(nameof(eventBus));
}
if (system == null)
{
throw new ArgumentNullException(nameof(system));
}
// When an observer subscribes, create an actor to represent them and subscribe it to the bus.
return(Observable.Create <TEventMessage>(async observer =>
{
// TODO: Push both subscriber creation and subscription to event bus down to the subscriber manager and have it unsubscribe when the subscribed actor stops (looks like this behaviour - ManagedActorClassification - is missing from CLR Akka).
// TODO: Consider having an actor to manage all interaction with the event bus.
IActorRef subscriber = await system.Reactive().CreateSubscriberAsync(observer);
eventBus.Subscribe(subscriber, subscriptionClassifier);
}));
}
public void EventBus_allow_subscribers()
{
_bus.Subscribe(_subscriber, _classifier).ShouldBe(true);
}