class ConfigObserver {

    public ConfigObserver onLongValue(String key, long defaultValue, ConfigValueListener<Long> listener) {
        return onSingleConfigValue(key, Long::parseLong, defaultValue, listener);
    }

    public  ConfigObserver(String applicationName);
    public  ConfigObserver(File configDirectory, String applicationName);
    public  ConfigObserver(File configDirectory, String applicationName, List<String> profiles);
    public  ConfigObserver(ConfigLoader configLoader);

}