public NlsMessageDescriptor getMessageRequired(String key) {

    NlsMessageDescriptor message = getMessage(key);
    if (message == null) {
      throw new IllegalArgumentException(key);
    }
    return message;
  }
public NlsMessageDescriptor getMessageRequired ( String key ) { NlsMessageDescriptor message = getMessage ( key ) ; if ( message == null ) { throw new IllegalArgumentException ( key ) ; } return message ; }
@param key the {@link NlsBundleKey#value() key} of the requested message.
@return the {@link NlsMessageDescriptor} for the given {@code key} or {@code null} if not present.