code: public String nextValue() throws IOException {
          Token tkn = nextToken();
          String ret = null;
          switch (tkn.type) {
              case TT_TOKEN:
              case TT_EORECORD:
                  ret = tkn.content.toString();
                  break;
              case TT_EOF:
                  ret = null;
                  break;
              case TT_INVALID:
              default:
                  // error no token available (or error)
                  throw new IOException(
                          "(line " + getLineNumber() + ") invalid parse sequence");
              /// unreachable: break;
          }
          return ret;
      }
docs: Parses the CSV according to the given strategy
  and returns the next csv-value as string.
  
  @return next value in the input stream ('null' when end of file)
  @throws IOException on parse error or input read-failure