flex eventBus

package com.wks.util
{
 import flash.events.Event;
 import flash.events.EventDispatcher;

 public class EventBus extends EventDispatcher
 {
  public function EventBus()
  {
  }
  private static var manager:EventBus;
  
  public static const CHANGEVIEW:String = "changeViewStackIndex";
  
  public static function getInstance():EventBus
  {
   if(!manager)manager = new EventBus;
   return manager;
  }
  public function dispatch(type:String):Boolean
  {
   return dispatchEvent(new Event(type));
  }
 }
}