Custom Symbol for Graphic using Flex API for ArcGIS

This is demonstration of a very simple custom symbol to render a graphic component on a map. Here is the application:

<?xml version="1.0" encoding="utf-8"?>
<mx:Application
    xmlns:mx="http://www.adobe.com/2006/mxml"
    xmlns:esri="http://www.esri.com/2008/ags"
    xmlns:test="com.esri.test.*"
    layout="absolute"
    >
    <esri:Map>
        <esri:GraphicsLayer>
            <esri:graphicProvider>
                <mx:ArrayCollection>
                    <esri:Graphic>
                        <esri:geometry>
                            <esri:MapPoint x="45" y="45"/>
                        </esri:geometry>
                        <esri:symbol>
                            <test:CustomSymbol/>
                        </esri:symbol>
                    </esri:Graphic>
                </mx:ArrayCollection>
            </esri:graphicProvider>
        </esri:GraphicsLayer>
    </esri:Map>    
</mx:Application>

And here is the CustomSymbol:

package com.esri.test
{
    import com.esri.ags.Graphic;
    import com.esri.ags.Map;
    import com.esri.ags.esri_internal;
    import com.esri.ags.geometry.MapPoint;
    import com.esri.ags.symbol.Symbol;

    use namespace esri_internal;
    
    public class CustomSymbol extends Symbol
    {
        public function CustomSymbol()
        {
            super();
        }
        
        override esri_internal function drawGraphic(
            map : Map,
            graphic : Graphic
        ) : void
        {
            if( graphic.geometry is MapPoint )
            {
                drawMapPoint( map, graphic, MapPoint( graphic.geometry ));
            }
        }
        
        private function drawMapPoint(
            map : Map,
            graphic : Graphic,
            mapPoint : MapPoint
        ) : void
        {
            graphic.x = map.mapToContainerX(mapPoint.x);
            graphic.y = map.mapToContainerY(mapPoint.y);
            
            graphic.graphics.clear();
            graphic.graphics.beginFill( 0xFF0000, 0.5 );
            graphic.graphics.drawCircle( 0, 0, 10 );
            graphic.graphics.endFill();            
        }            
                
    }
}

Be warned - this uses an esri_internal function that is subject to change without notice :-(