Java - map key lookup ignoring case

Question

I'm writing a script that creates a map from user nicknames to user IDs:

// Get client informations to map
for (Client c : api.getClients()) {
  teamspeakUserInfos.put(c.getNickname(), c.getId());
}

Example mapping:

Nickname | 5
Username | 2
John     |12

Here is my code for checking key presence in the map:

if (teamspeakUserInfos.containsKey(genUserNickname())) {
  victimTeamspeakID = teamspeakUserInfos.get(genUserNickname());
  break;
}

genUserNickname() can return upper-, lower- or mixed-case nickname.

My question now is, how can I check if this nickname is used as a key - while ignoring case differences?

Thank you in advance!

Answer 1

You could do something similar:

public class ContainsKeyIgnoreCase {

    public static void main(String[] args) {

        Map<String, Integer> userInfo = new HashMap<String, Integer>();
        userInfo.put("nickNamE", 1);

        String nickName = "NiCKname";

        System.out.println(containsKeyIgnoreCase(userInfo, nickName));
    }

    public static boolean containsKeyIgnoreCase(Map<String, Integer> map, String lookupKey) {
        return map.keySet()
                  .stream()
                  .map(key -> key.equalsIgnoreCase(lookupKey))
                  .reduce(false, Boolean::logicalOr);
    }   
}