make locale matching a tiny bit faster for legacy

Author: xGinko

shared/src/main/java/me/xginko/aef/utils/LocaleUtil.java

@@ -1,15 +1,20 @@
 package me.xginko.aef.utils;
 
+import java.util.HashMap;
 import java.util.Locale;
+import java.util.Map;
 import java.util.regex.Pattern;
 
 public final class LocaleUtil {
 
     public static final Pattern LANGUAGE_TAG_PATTERN = Pattern.compile("([a-z]{1,3}_[a-z]{1,3})(\\.yml)", Pattern.CASE_INSENSITIVE);
 
+    private static final Map<String, Locale> LANGTAG_LOCALE_MAP = new HashMap<>(); // This is so unnecessary but it makes me happy
     public static Locale localeForLanguageTag(String languageTag) {
-        Locale match = Locale.forLanguageTag(languageTag.toLowerCase(Locale.ROOT).replace('_', '-'));
-        return match == Locale.ROOT ? Locale.US : match;
+        return LANGTAG_LOCALE_MAP.computeIfAbsent(languageTag, tag -> {
+            Locale match = Locale.forLanguageTag(tag.toLowerCase(Locale.ROOT).replace('_', '-'));
+            return match == Locale.ROOT ? Locale.US : match;
+        });
     }
 
     public static String languageTagForLocale(Locale locale) {