Ping Service

package com.hbo.diagnostics.services
{
    import com.hbo.diagnostics.events.ServiceEvent;

    import flash.events.ErrorEvent;
    import flash.events.Event;
    import flash.events.EventDispatcher;
    import flash.events.HTTPStatusEvent;
    import flash.events.IEventDispatcher;
    import flash.events.IOErrorEvent;
    import flash.events.SecurityErrorEvent;
    import flash.net.URLLoader;
    import flash.net.URLRequest;

    [Event(name="pingSuccess", type="com.hbo.diagnostics.events.ServiceEvent")]
    [Event(name="pingError", type="com.hbo.diagnostics.events.ServiceEvent")]
    public class PingService extends EventDispatcher
    {
        private var loader:URLLoader;
        public var url:String;
        private var _loading:Boolean = false;

        public function get loading():Boolean { return _loading; }

        public function PingService()
        {
            super();
        }

        public function ping(url:String=null):void
        {
            if(_loading == true)
                return;

            if(url != null && url != "")
                this.url = url;

            if(loader == null)
            {
                loader = new URLLoader();
                loader.addEventListener(Event.COMPLETE, onComplete);
                loader.addEventListener(HTTPStatusEvent.HTTP_RESPONSE_STATUS, onResponseStatus);
                loader.addEventListener(HTTPStatusEvent.HTTP_STATUS, onResponseStatus);
                loader.addEventListener(IOErrorEvent.IO_ERROR, onError);
                loader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, onError);
            }

            try
            {
                loader.close();
            }
            catch(error:Error)
            {
            }

            try
            {
                _loading = true;
                loader.load(new URLRequest(this.url));
            }
            catch(error:Error)
            {
                //trace("PingService::ping, error: " + error);
                _loading = false;
                dispatchEvent(new ServiceEvent(ServiceEvent.PING_ERROR));
            }
        }

        private function onComplete(event:Event):void
        {
            //trace("PingService::onComplete");
            _loading = false;
            dispatchEvent(new ServiceEvent(ServiceEvent.PING_SUCCESS));
        }

        private function onError(event:ErrorEvent):void
        {
            //trace("PingService::onError");
            //trace(event.text);
            _loading = false;
            dispatchEvent(new ServiceEvent(ServiceEvent.PING_ERROR));
        }

        private function onResponseStatus(event:HTTPStatusEvent):void
        {
            //trace("PingService::onResponseStatus");
            //trace(event.status);
        }

    }
}