public class

SimpleEventBus

extends EventBus
java.lang.Object
   ↳ com.google.gwt.event.shared.EventBus
     ↳ com.google.gwt.event.shared.SimpleEventBus

Class Overview

Basic implementation of EventBus.

Summary

Public Constructors
SimpleEventBus()
Public Methods
<H extends EventHandler> HandlerRegistration addHandler(Type<H> type, H handler)
Adds an unfiltered handler to receive events of this type from all sources.
<H extends EventHandler> HandlerRegistration addHandlerToSource(Type<H> type, Object source, H handler)
Adds a handler to receive events of this type from the given source.
void fireEvent(GwtEvent<?> event)
Fires the event from no source.
void fireEventFromSource(GwtEvent<?> event, Object source)
Fires the given event to the handlers listening to the event's type.
[Expand]
Inherited Methods
From class com.google.gwt.event.shared.EventBus
From class java.lang.Object
From interface com.google.gwt.event.shared.HasHandlers

Public Constructors

public SimpleEventBus ()

Public Methods

public HandlerRegistration addHandler (Type<H> type, H handler)

Adds an unfiltered handler to receive events of this type from all sources.

It is rare to call this method directly. More typically a GwtEvent subclass will provide a static register method, or a widget will accept handlers directly.

A tip: to make a handler de-register itself, the following works:

new MyHandler() {
  HandlerRegistration reg = MyEvent.register(eventBus, this);
 
  public void onMyThing(MyEvent event) {
    /* do your thing */
    reg.removeHandler();
  }
 };
 

Parameters
type the event type associated with this handler
handler the handler
Returns
  • the handler registration, can be stored in order to remove the handler later

public HandlerRegistration addHandlerToSource (Type<H> type, Object source, H handler)

Adds a handler to receive events of this type from the given source.

It is rare to call this method directly. More typically a GwtEvent subclass will provide a static register method, or a widget will accept handlers directly.

Parameters
type the event type associated with this handler
source the source associated with this handler
handler the handler
Returns
  • the handler registration, can be stored in order to remove the handler later

public void fireEvent (GwtEvent<?> event)

Fires the event from no source. Only unfiltered handlers will receive it.

Parameters
event the event to fire

public void fireEventFromSource (GwtEvent<?> event, Object source)

Fires the given event to the handlers listening to the event's type.

Any exceptions thrown by handlers will be bundled into a UmbrellaException and then re-thrown after all handlers have completed. An exception thrown by a handler will not prevent other handlers from executing.

Parameters
event the event to fire