code: public void parseQuery() throws TTXPathException {
  
          // get first token, ignore all white spaces
          do {
              mToken = mScanner.nextToken();
          } while (mToken.getType() == TokenType.SPACE);
  
          // parse the query according to the rules specified in the XPath 2.0 REC
          parseExpression();
  
          // after the parsing of the expression no token must be left
          if (mToken.getType() != TokenType.END) {
              throw new IllegalStateException("The query has not been processed completely.");
          }
      }
docs: Starts parsing the query.
  
  @throws TTXPathException