code: public static boolean containsIgnoreCase(final String source, final String target) {
  
      if (source != null && target != null) {
        return indexOfIgnoreCase(source, target) != INDEX_OF_NOT_FOUND;
      } else {
        return false;
      }
    }
docs: Returns true if given string contains given target string ignore case,
  false otherwise.<br>
  
  @param source string to be tested.
  @param target string to be tested.
  @return true if given string contains given target string ignore case,
  false otherwise.