latches in flex

latches.mxml

<fx:Script>
    import flash.external.*;

     public function initApp():void {
        // flexpilot
        FPBootstrap.flex_pilotLibPath = 'FlexPilot.swf';
        FPBootstrap.init(stage);
        
        // latch stuff
        var latches:Object = new Object();
        ExternalInterface.addCallback("WebDriverLatch", getLatchStatus);
     }  

     // what's called via the external interface 
     public function getLatchStatus(s:String):String {
        return latches[s];
     }
     
     public function setLatchStatus(l:String, v:String):void {
        latches[l] = v;
     }
</fx:Script>