Starting to add custom messages to AntiVPN

Common/src/main/java/dev/brighten/antivpn/message/MessageHandler.java

@@ -0,0 +1,39 @@
+package dev.brighten.antivpn.message;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+
+public class MessageHandler {
+    private final Map<String, VpnString> messages = new HashMap<>();
+
+    public VpnString getString(String key) {
+        if(!messages.containsKey(key)) {
+            throw new NullPointerException("There is no VpnString with the key \"" + key + "\"");
+        }
+
+        return messages.get(key);
+    }
+
+    public void reloadStrings() {
+        for (VpnString value : messages.values()) {
+            value.updateString();
+        }
+    }
+
+    public void clearStrings() {
+        messages.clear();
+    }
+
+    public void addString(VpnString string, Function<VpnString, String> getter) {
+        string.setConfigStringGetter(getter);
+        messages.put(string.getKey(), string);
+    }
+
+    public void initStrings(Function<VpnString, String> getter) {
+        addString(new VpnString("command-misc-playerRequired",
+                "&cYou must be a player to execute this command!"), getter);
+        addString(new VpnString("command-alerts-toggled",
+                "&7Your player proxy notifications have been set to: &e%state%"), getter);
+    }
+}