Improve Event Aggregator Javadoc

Author: iluwatar

event-aggregator/src/main/java/com/iluwatar/event/aggregator/App.java

@@ -5,8 +5,12 @@
 
 /**
  * 
- * The Event Aggregator pattern channels events from multiple objects 
- * into a single object to simplify registration for clients.
+ * A system with lots of objects can lead to complexities when a client wants to subscribe 
+ * to events. The client has to find and register for each object individually, if each 
+ * object has multiple events then each event requires a separate subscription.
+ * <p>
+ * An Event Aggregator acts as a single source of events for many objects. It registers 
+ * for all the events of the many objects allowing clients to register with just the aggregator.
  * <p>
  * In the example {@link LordBaelish}, {@link LordVarys} and {@link Scout} deliver events to
  * {@link KingsHand}. {@link KingsHand}, the event aggregator, then delivers the events