analytics/webcontent/ags/eventHandlerUtil.js

/**************************************************************************
* Licensed Materials - Property of IBM                                    *
*                                                                         *
* IBM Cognos Products: AGS                                                *
*                                                                         *
* (C) Copyright IBM Corp. 2005, 2017                                      *
*                                                                         *
* US Government Users Restricted Rights - Use, duplication or disclosure  *
* restricted by GSA ADP Schedule Contract with IBM Corp.                  *
***************************************************************************/

// -----------------------------------------------------------------------------
//
// --- event listener utility --- 
//
// -----------------------------------------------------------------------------

//object to ease the chaining of event handlers, in order to allow users to add more than one handler to a control
function EventHandlerChain(name, handler){
	this.eventName = name;
	this.functionRefs = new Array();
	this.addHandler(handler);	
}

EventHandlerChain.prototype.setEventHandlerChain = function(an_object){
	if (an_object) {
		if (cf.browserCheck.isIE5Up()) {
			an_object.attachEvent("on" + this.eventName,this.handleEvent);
		}	
		else if (cf.browserCheck.isNav6Up()) {
			an_object.addEventListener(this.eventName,this.handleEvent,true);
		}
		an_object[eventHandlerChainUtil.getPropertyName(this.eventName)] = this;
	}
}

EventHandlerChain.prototype.addHandler = function(handler){
	this.functionRefs.push(handler);	
}

EventHandlerChain.prototype.handleEvent = function(event){
	
	if(!this.eventName){
		//find the right instance
		if (!event) event=arguments.callee.caller.arguments[0];
		var control=event.srcElement || event.currentTarget || event.target;
		
		var evtName = eventHandlerChainUtil.getPropertyName(event.type);
		
		var ehc = eventHandlerChainUtil.getEventHandlerChain(control, evtName);
		
		if (ehc) {
		    ehc.handleEvent(event);
 		}
		
		return;
	}
	
	for(var i = 0; i < this.functionRefs.length; i++){
		if(this.functionRefs[i]){
			if (typeof this.functionRefs[i] == "object" && this.functionRefs[i].update) {
				//callback on the object itself (used by eventNotification framework)
				this.functionRefs[i].update(event);
			} else {
				//should be a function
				this.functionRefs[i](event);
			}
		}
	}	
}

function EventHandlerChainUtil(){
	
	return this.PROPERTY_NAME = "event_handler_chain";	
}

EventHandlerChainUtil.prototype.getPropertyName = function(event_name){
	
	return this.PROPERTY_NAME + "_" + event_name;
}

EventHandlerChainUtil.prototype.getEventHandlerChain = function(an_object, property_name){
	//var property_name = this.getPropertyName(event_name);
	
	var ehc;
	
	//the event source object may not have had the handler applied
	if(an_object && an_object[property_name]){
		ehc = an_object[property_name];
	}else if(an_object){
		ehc = this.getEventHandlerChain(an_object.parentNode, property_name);
	}
	return ehc;
	
	
}

//utility to check and then initialise or add to event handler chain for this object event and handler
EventHandlerChainUtil.prototype.doEventHandlerChain = function(an_object, event_name, handler){
    var property_name = this.getPropertyName(event_name);
	var ehc = this.getEventHandlerChain(an_object,property_name);
	
	if(!ehc){
		ehc = new EventHandlerChain(event_name, handler);
		ehc.setEventHandlerChain(an_object);
	}else{
		ehc.addHandler(handler);
	}
}

var eventHandlerChainUtil = new EventHandlerChainUtil();