class ConfigObserver {

    public ConfigObserver onIntValue(String key, int defaultValue, ConfigValueListener<Integer> listener) {
        return onSingleConfigValue(key, Integer::parseInt, 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);

}