code: public Position getPosition(final String pos) {
          final String s = pos.toUpperCase(Locale.US);
          final int len = s.length();
          int status = 0;
  
          int row = 0;
          int col = 0;
          int n = 0;
          while (n < len) {
              final char c = s.charAt(n);
              switch (status) {
                  case BEGIN_LETTER: // opt $
                  case BEGIN_DIGIT: // opt $
                      status++;
                      if (c == '$') n++;
                      break;
                  case FIRST_LETTER: // mand letter
                      if ('A' <= c && c <= 'Z') {
                          col = c - 'A' + 1;
                          status = PositionUtil.OPT_SECOND_LETTER;
                          n++;
                      } else return null;
                      break;
                  case OPT_SECOND_LETTER: // opt letter
                      if ('A' <= c && c <= 'Z') {
                          col = col * ALPHABET_SIZE + c - ORD_A + 1;
                          n++;
                      }
                      status = PositionUtil.BEGIN_DIGIT;
                      break;
                  case FIRST_DIGIT: // mand digit
                      if ('0' <= c && c <= '9') {
                          row = c - '0';
                          status = PositionUtil.OPT_DIGIT;
                          n++;
                      } else return null;
                      break;
                  case OPT_DIGIT: // opt digit
                      if ('0' <= c && c <= '9') {
                          row = row * 10 + c - '0';
                          n++;
                      } else return null;
                      break;
                  default:
                      return null;
              }
          }
          return new Position(this.equalityUtil, this.tableNameUtil, row - 1, col - 1);
      }
docs: Convert a cell position string like B3 to the column number.
  
  @param pos The cell position in the range 'A1' to 'IV65536'
  @return The row, e.g. A1 will return 0, B1 will return 1, E1 will return
  4