protected Configuration parseConfigFile(String configFileName) throws ConfigurationException {
        if (configFileName == null) {
            return null;
        }
        Configuration out = null;
        String ext = FilenameUtils.getExtension(configFileName);
        if (StringUtils.equalsIgnoreCase("xml", ext)) {
            out = new XMLConfiguration(configFileName);
        }
        else if (StringUtils.equalsIgnoreCase("properties", ext)) {
            out = new PropertiesConfiguration(configFileName);
        }
        return out;
    }