docs: event stream document without typed case (akka#29109)

akka-docs/src/main/paradox/event-bus.md

@@ -1,51 +1,32 @@
 # Classic Event Bus
 
-Originally conceived as a way to send messages to groups of actors, the
-@scala[@scaladoc[EventBus](akka.event.EventBus)]@java[@javadoc[EventBus](akka.event.japi.EventBus)] has been generalized into a set of @scala[composable traits] @java[abstract base classes]
-implementing a simple interface:
+@@include[includes.md](includes.md) { #actor-api }
+For the full documentation of this feature and for new projects see @ref:[Event Bus](typed/event-bus.md).
 
-Scala
-:  @@snip [EventBus.scala](/akka-actor/src/main/scala/akka/event/EventBus.scala) { #event-bus-api }
+## Dependency
 
-Java
-:  @@snip [EventBusDocTest.java](/akka-docs/src/test/java/jdocs/event/EventBusDocTest.java) { #event-bus-api }
+@@include[typed/event-bus.md](typed/event-bus.md) { #dependency }
 
-@@@ note
+## Introduction
 
-Please note that the EventBus does not preserve the sender of the
-published messages. If you need a reference to the original sender
-you have to provide it inside the message.
+@@include[typed/event-bus.md](typed/event-bus.md) { #introduction-start }
 
-@@@
-
-This mechanism is used in different places within Akka, e.g. the @ref:[Event Stream](#event-stream).
-Implementations can make use of the specific building blocks presented below.
+Scala
+:  @@snip [EventBus.scala](/akka-actor/src/main/scala/akka/event/EventBus.scala) { #event-bus-api }
 
-An event bus must define the following three @scala[abstract types]@java[type parameters]:
+Java
+:  @@snip [EventBusDocTest.java](/akka-docs/src/test/java/jdocs/event/EventBusDocTest.java) { #event-bus-api }
 
- * `Event` is the type of all events published on that bus
- * `Subscriber` is the type of subscribers allowed to register on that event bus
- * `Classifier` defines the classifier to be used in selecting
-subscribers for dispatching events
+@@include[typed/event-bus.md](typed/event-bus.md) { #introduction-end }
 
-The traits below are still generic in these types, but they need to be defined
-for any concrete implementation.
 
 ## Classifiers
 
-The classifiers presented here are part of the Akka distribution, but rolling
-your own in case you do not find a perfect match is not difficult, check the
-implementation of the existing ones on @extref[github](github:akka-actor/src/main/scala/akka/event/EventBus.scala) 
+@@include[typed/event-bus.md](typed/event-bus.md) { #classifiers-intro }
 
 ### Lookup Classification
 
-The simplest classification is just to extract an arbitrary classifier from
-each event and maintaining a set of subscribers for each possible classifier.
-This can be compared to tuning in on a radio station. The @scala[trait
-@scaladoc[LookupClassification](akka.event.LookupClassification)]@java[abstract class @scaladoc[LookupEventBus](akka.event.japi.LookupEventBus)] is still generic in that it abstracts over how to
-compare subscribers and how exactly to classify them.
-
-The necessary methods to be implemented are illustrated with the following example:
+@@include[typed/event-bus.md](typed/event-bus.md) { #lookup-classification-start }
 
 Scala
 :  @@snip [EventBusDocSpec.scala](/akka-docs/src/test/scala/docs/event/EventBusDocSpec.scala) { #lookup-bus }
@@ -61,19 +42,11 @@ Scala
 Java
 :  @@snip [EventBusDocTest.java](/akka-docs/src/test/java/jdocs/event/EventBusDocTest.java) { #lookup-bus-test }
 
-This classifier is efficient in case no subscribers exist for a particular event.
+@@include[typed/event-bus.md](typed/event-bus.md) { #lookup-classification-end }
 
 ### Subchannel Classification
 
-If classifiers form a hierarchy and it is desired that subscription be possible
-not only at the leaf nodes, this classification may be just the right one. It
-can be compared to tuning in on (possibly multiple) radio channels by genre.
-This classification has been developed for the case where the classifier is
-just the JVM class of the event and subscribers may be interested in
-subscribing to all subclasses of a certain class, but it may be used with any
-classifier hierarchy.
-
-The necessary methods to be implemented are illustrated with the following example:
+@@include[typed/event-bus.md](typed/event-bus.md) { #subchannel-classification-start }
 
 Scala
 :  @@snip [EventBusDocSpec.scala](/akka-docs/src/test/scala/docs/event/EventBusDocSpec.scala) { #subchannel-bus }
@@ -89,21 +62,11 @@ Scala
 Java
 :  @@snip [EventBusDocTest.java](/akka-docs/src/test/java/jdocs/event/EventBusDocTest.java) { #subchannel-bus-test }
 
-This classifier is also efficient in case no subscribers are found for an
-event, but it uses conventional locking to synchronize an internal classifier
-cache, hence it is not well-suited to use cases in which subscriptions change
-with very high frequency (keep in mind that “opening” a classifier by sending
-the first message will also have to re-check all previous subscriptions).
+@@include[typed/event-bus.md](typed/event-bus.md) { #subchannel-classification-end }
 
 ### Scanning Classification
 
-The previous classifier was built for multi-classifier subscriptions which are
-strictly hierarchical, this classifier is useful if there are overlapping
-classifiers which cover various parts of the event space without forming a
-hierarchy. It can be compared to tuning in on (possibly multiple) radio
-stations by geographical reachability (for old-school radio-wave transmission).
-
-The necessary methods to be implemented are illustrated with the following example:
+@@include[typed/event-bus.md](typed/event-bus.md) { #scanning-classification-start }
 
 Scala
 :  @@snip [EventBusDocSpec.scala](/akka-docs/src/test/scala/docs/event/EventBusDocSpec.scala) { #scanning-bus }
@@ -119,21 +82,16 @@ Scala
 Java
 :  @@snip [EventBusDocTest.java](/akka-docs/src/test/java/jdocs/event/EventBusDocTest.java) { #scanning-bus-test }
 
-This classifier takes always a time which is proportional to the number of
-subscriptions, independent of how many actually match.
+@@include[typed/event-bus.md](typed/event-bus.md) { #scanning-classification-end }
+
 
 ### Actor Classification
 
 This classification was originally developed specifically for implementing
-@ref:[DeathWatch](actors.md#deathwatch): subscribers as well as classifiers are of
+@ref:[DeathWatch](actors.md#lifecycle-monitoring-aka-deathwatch): subscribers as well as classifiers are of
 type @apidoc[actor.ActorRef].
 
-This classification requires an @apidoc[actor.ActorSystem] in order to perform book-keeping
-operations related to the subscribers being Actors, which can terminate without first
-unsubscribing from the EventBus. ManagedActorClassification maintains a system Actor which
-takes care of unsubscribing terminated actors automatically.
-
-The necessary methods to be implemented are illustrated with the following example:
+@@include[typed/event-bus.md](typed/event-bus.md) { #actor-classification-start }
 
 Scala
 :  @@snip [EventBusDocSpec.scala](/akka-docs/src/test/scala/docs/event/EventBusDocSpec.scala) { #actor-bus }
@@ -149,8 +107,8 @@ Scala
 Java
 :  @@snip [EventBusDocTest.java](/akka-docs/src/test/java/jdocs/event/EventBusDocTest.java) { #actor-bus-test }
 
-This classifier is still is generic in the event type, and it is efficient for
-all use cases.
+@@include[typed/event-bus.md](typed/event-bus.md) { #actor-classification-end }
+
 
 ## Event Stream
 

akka-docs/src/main/paradox/index-utilities.md

@@ -4,6 +4,7 @@
 
 @@@ index
 
+* [event-bus](typed/event-bus.md)
 * [logging](typed/logging.md)
 * [common/circuitbreaker](common/circuitbreaker.md)
 * [futures](futures.md)