// JavaScript Document
/**
 * @author 		Matthew Foster
 * @date		June 6th 2007
 * @purpose		To have a base class to extend subclasses from to inherit event dispatching functionality.
 * @procedure	Use a hash of event "types" that will contain an array of functions to execute.  The logic is if any function explicitally returns false the chain will halt execution.
 */
 var EventDispatcher = Class.create({});
Object.extend(EventDispatcher.prototype,
{
buildListenerChain : function(){
if(!this.listenerChain)
this.listenerChain = {};							
},
addEventListener : function(type, listener){
this.buildListenerChain();
if(!this.listenerChain[type])					
this.listenerChain[type] = [listener];
else
this.listenerChain[type].push(listener);
},
hasEventListener : function(type){
return (typeof this.listenerChain[type] != "undefined");
},
removeEventListener : function(type, listener){
if(!this.hasEventListener(type))
return false;
for(var i = 0; i < this.listenerChain[type].length; i++)
if(this.listenerChain[type][i] == listener)
this.listenerChain[type].splice(i, 1);
},
dispatchEvent : function(type, args){
this.buildListenerChain();
if(!this.hasEventListener(type))
return false;
this.listenerChain[type].any(function(f){ return (f(args) == false ? true : false); });						
},
on : function(type, listener){
this.addEventListener(type, listener);
},
fire : function(type, args){
this.dispatchEvent(type, args);
}
}
);