!act,doc #2922 Doc event bus and fix Java API

akka-actor/src/main/scala/akka/event/EventBus.scala

@@ -23,15 +23,18 @@ trait EventBus {
   type Classifier
   type Subscriber
 
+  //#event-bus-api
   /**
    * Attempts to register the subscriber to the specified Classifier
-   * @return true if successful and false if not (because it was already subscribed to that Classifier, or otherwise)
+   * @return true if successful and false if not (because it was already
+   *   subscribed to that Classifier, or otherwise)
    */
   def subscribe(subscriber: Subscriber, to: Classifier): Boolean
 
   /**
    * Attempts to deregister the subscriber from the specified Classifier
-   * @return true if successful and false if not (because it wasn't subscribed to that Classifier, or otherwise)
+   * @return true if successful and false if not (because it wasn't subscribed
+   *   to that Classifier, or otherwise)
    */
   def unsubscribe(subscriber: Subscriber, from: Classifier): Boolean
 
@@ -44,6 +47,7 @@ trait EventBus {
    * Publishes the specified Event to this bus
    */
   def publish(event: Event): Unit
+  //#event-bus-api
 }
 
 /**
@@ -118,6 +122,9 @@ trait LookupClassification { this: EventBus ⇒
  */
 trait SubchannelClassification { this: EventBus ⇒
 
+  /**
+   * The logic to form sub-class hierarchy
+   */
   protected implicit def subclassification: Subclassification[Classifier]
 
   // must be lazy to avoid initialization order problem with subclassification