Flex 事件分发(FlexViewer事件机制)剥离过程

package com 
{ 
import flash.events.event; 

/** 
* @author samsung 
* 创建时间：2014-7-24 下午1:21:05 
* 
*/ 
public class appevent extends event 
{ 
//-------------------------------------------------------------------------- 
// 
// properties 
// 
//-------------------------------------------------------------------------- 

private var _data:object; 

private var _callback:function; 

public function appevent(type:string, data:object = null, callback:function = null) 
{ 
super(type); 
_data = data; 
_callback = callback; 
} 


/** 
* the data will be passed via the event. it allows the event dispatcher to publish 
* data to event listener(s). 
*/ 
public function get data():object 
{ 
return _data; 
} 

/** 
* @private 
*/ 
public function set data(value:object):void 
{ 
_data = value; 
} 

/** 
* the callback function associated with this event. 
*/ 
public function get callback():function 
{ 
return _callback; 
} 

/** 
* @private 
*/ 
public function set callback(value:function):void 
{ 
_callback = value; 
} 

/** 
* override clone 
*/ 
public override function clone():event 
{ 
return new appevent(this.type, this.data, this.callback); 
} 

/** 
* dispatch this event. 
*/ 
public function dispatch():boolean 
{ 
return eventbus.instance.dispatchevent(this); 
} 

/** 
* dispatch an appevent for specified type and with optional data and callback reference. 
*/ 
public static function dispatch(type:string, data:object = null, callback:function = null):boolean 
{ 
return eventbus.instance.dispatchevent(new appevent(type, data, callback)); 
} 

public static function addlistener(type:string, listener:function, usecapture:boolean = false, priority:int = 0, useweakreference:boolean = false):void 
{ 
eventbus.instance.addeventlistener(type, listener, usecapture, priority, useweakreference); 
} 

public static function removelistener(type:string, listener:function, usecapture:boolean = false):void 
{ 
eventbus.instance.removeeventlistener(type, listener, usecapture); 
} 

} 
}

package com 
{ 
import flash.events.event; 
import flash.events.eventdispatcher; 

/** 
* the eventbus allows centrallized communication among modules without 
* point-to-point messaging. it uses the singleton design pattern 
* to make sure one event bus is available globally. the bus itself 
* is only available to the container. modules use the container's 
* static method to communicate with the event bus. 
*/ 
public class eventbus extends eventdispatcher 
{ 
/** application event bus instance */ 
public static const instance:eventbus = new eventbus(); 

/** 
* normally the eventbus is not instantiated via the <b>new</b> method directly. 
* the constructor helps enforce only one evenbus availiable for the application 
* (singeton) so that it asures the communication only via a sigle event bus. 
*/ 
public function eventbus() 
{ 
} 

/** 
* the factory method is used to create a instance of the eventbus. it returns 
* the only instanace of eventbus and makes sure no another instance is created. 
*/ 
[deprecated(replacement="instance")] 
public static function getinstance():eventbus 
{ 
return instance; 
} 

/** 
* basic dispatch function, dispatches simple named events. in the case 
* that the event is only significant by the event token (type string), 
* this new dispatch method simplify the code. 
*/ 
[deprecated(replacement="appevent.dispatch")] 
public function dispatch(type:string):boolean 
{ 
return dispatchevent(new event(type)); 
} 
} 
}