com.ekuefler.supereventbus.multievent
Class MultiEvent

java.lang.Object
  com.ekuefler.supereventbus.multievent.MultiEvent

public class MultiEvent
extends Object

An event wrapping another event that could be one of several unrelated types. This allows a handler method to handle events of multiple types that are not assignable to each other. For example, the following method would be invoked whenever Strings or Doubles were posted on the event bus:

 @Subscribe
 void handleMultipleTypes(@EventTypes({String.class, Double.class}) MultiEvent event) {
   if (event instanceof String) {
     Window.alert("Got a string: " + event.getEvent());
   } else if (event instanceof Double) {
     Window.alert("Got a double: " + event.getEvent());
   }
 }
 

Note the use of the EventTypes annotation to indicate which types of events should be handled. Parameters of type MultiEvent in Subscribe-annotated methods must always contain this annotation.

Also note that this technique should be used relatively sparingly. Most of the time, events that should be handled in the same way should be made to extend a common base class or interface, in which case that type can be made the argument to the handler method instead of MultiEvent. MultiEvent should only be used to handle events of unrelated types that can't be made to extend a common base.

Instances of MultiEvent are created automatically by the event bus - users should never instantiate or post these events on the event bus.

Author:

ekuefler@gmail.com (Erik Kuefler)

Constructor Summary

MultiEvent(Object event)
Instantiates a new MultiEvent wrapping the given event.

Method Summary

Object

getEvent() Returns the underlying event that this event wraps, which will be of a type assignable to one of the types declared in the EventTypes annotation for this parameter.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MultiEvent

public MultiEvent(Object event)

Instantiates a new MultiEvent wrapping the given event. Users should never have to invoke this method directly.

Method Detail

getEvent

public Object getEvent()

Returns the underlying event that this event wraps, which will be of a type assignable to one of the types declared in the EventTypes annotation for this parameter.