I have an established pattern for lazy loading data from a server via AMF.
private var _XeventDispatched:Boolean;
private var _X:ArrayCollection;
public function get X():ArrayCollection{
if(!_XeventDispatched && (_X==null || _X.length==0)){
var evt:Event = new Event();//whatever event is need for this data member
dispatcher.dispatchEvent(evt);
_XeventDispatched = true;
}
return _X;
}
public function set X(ac:ArrayCollection):void{
return _X;
}
This way the data is not loaded from the server until it is needed. (I'm using the Mate framework by the way, so when a UI is instanciated, and the injectors fire, they call this get method in the data manager class.)
What I'd like to do is create some kind of Metadata tag, similar to [Bindable] that will add the above methods in place of a public property.
[LazyLoaded(eventName="com.myCompany.LoadX")]
public var X:ArrayCollection;
Does the compiler have any hooks for this type of extension? It would save a lot of boiler plate code that is hard to read.
+1 Marty you lead me to this, but its different from your solution.
I've created a base class (BaseDataManager) that all other Mate data managers can extend from, and in that class I've added the below code:
private var eventsDispatched:Array = new Array();
protected function lazyLoad(value:*, eventType:String):*{
if(!eventsDispatched[event] && (value==null || (value is IList && IList(value).length==0))){
var clazzName:String = eventType.substr(0, eventType.indexOf(":"));
var eventClazz:Class = Class(getDefinitionByName(clazzName));
var event:Event = new eventClazz(eventType);
dispatcher.dispatchEvent(event);
eventsDispatched[event] = true;
}
return value;
}
Then within each data manager, if the property is to be lazy loaded, this is their accessors:
private var _X:ArrayCollection;
public function get X():ArrayCollection{
return lazyLoad(_X, XLoadEvent.LOAD_EVENT_TYPE);
}
public function set X(value:ArrayCollection):void{
_X = value;
}
This way most of the ugly, hard to read code is hidden away from the dev, yet still accessible for debugging if any problems were to arise.