code: public static void notEmpty(String string, String message) {
          if (LettuceStrings.isEmpty(string)) {
              throw new IllegalArgumentException(message);
          }
      }
docs: Assert that a string is not empty, it must not be {@code null} and it must not be empty.
  
  @param string the object to check
  @param message the exception message to use if the assertion fails
  @throws IllegalArgumentException if the object is {@code null} or the underlying string is empty