source: code/Website/open-flash-chart/ExternalInterfaceManager.as

package {
        import flash.external.ExternalInterface;
        
        /**
         * This manages all External calls, not all players have this ability (Flex does not,
         * flash in a browser does, flash standalone does not)
         * 
         * We also have an optional chart_id that the user may set, this is passed out
         * as parameter one if it is set.
         */
        public class ExternalInterfaceManager
        {
                public var has_id:Boolean;
                public var chart_id:String;
                
                private static var _instance:ExternalInterfaceManager;
                
                public static function getInstance():ExternalInterfaceManager {
                        
                        if (_instance == null) {
                                _instance = new ExternalInterfaceManager();
                        }
                        
                        return _instance;
                }
                
                public function setUp(chart_id:String):void {
                        this.has_id = true;
                        this.chart_id = chart_id;
        tr.aces('this.chart_id',this.chart_id);
                }
                
                // THIS NEEDS FIXING. I can't figure out how to preprend the chart
                // id to the optional parameters.
                public function callJavascript(functionName:String, ... optionalArgs ): * {
                        
                        // the debug player does not have an external interface
                        // because it is NOT embedded in a browser
                        if (ExternalInterface.available) {
                                if ( this.has_id ) {
                                        tr.aces(functionName, optionalArgs);
                                        optionalArgs.unshift(this.chart_id);
                                        tr.aces(functionName, optionalArgs);
                                }
                                
                                return ExternalInterface.call(functionName, optionalArgs);
                        }
                        
                }
        }
}