public static function getSingletonInstance($className, array $arguments = array())
    {	
    	
    	$registerKey = $className;
    
        if (!isset(self::$_registry[$registerKey])) {

        	if(class_exists($className)) {
            	self::$_registry[$registerKey] = new $className($arguments);
            	
        	}else {
 
        		throw new Exception ('Invalid class name:: ' .$className."(".print_r($arguments,1).')');
        	}
        }


        return  self::$_registry[$registerKey];
    }