code: public static boolean isValidIANAEncoding(String ianaEncoding) {
          if (ianaEncoding != null) {
              int length = ianaEncoding.length();
              if (length > 0) {
                  char c = ianaEncoding.charAt(0);
                  if ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')) {
                      for (int i = 1; i < length; i++) {
                          c = ianaEncoding.charAt(i);
                          if ((c < 'A' || c > 'Z') && (c < 'a' || c > 'z') &&
                              (c < '0' || c > '9') && c != '.' && c != '_' &&
                              c != '-') {
                              return false;
                          }
                      }
                      return true;
                  }
              }
          }
          return false;
      }
docs: Returns true if the encoding name is a valid IANA encoding.
  This method does not verify that there is a decoder available
  for this encoding, only that the characters are valid for an
  IANA encoding name.
  
  @param ianaEncoding The IANA encoding name.