Problem with config.

Hi,
Im creating user info module to my plugin, and I have prolem with getting their UUID by name (or discordid, both strings). I need function that will do that I explained in gist below:
https://gist.github.com/YTSkaGamerPL/51cb59a627fbade4fe1bac2964d33793
Can someone help?

EDIT - I want code to be clear, no Lambda expressions or harder functions if possible - it will be easyer for me to understand it

 

Well, I don't know a more efficient way but this would work:

Code:

String getUserUUID(String value, String index) {
  if (!index.equalsIgnoreCase("nick") && !index.equalsIgnoreCase("discordid")) return null;

  ConfigurationSection keys = (plugin_instance).getConfig().getConfigurationSection("users");
  if (keys == null) return null;

  for (String uuid : keys.getKeys(false)) {
    String data = (plugin_instance).getConfig().getString("users." + uuid + "." + index);
    if (!data.equalsIgnoreCase(value)) continue;
    return uuid;
  }
  return null;
}