KsqlParser.java 文件源码

private ParserRuleContext getParseTree(String sql) {

    SqlBaseLexer
        sqlBaseLexer =
        new SqlBaseLexer(new CaseInsensitiveStream(new ANTLRInputStream(sql)));
    CommonTokenStream tokenStream = new CommonTokenStream(sqlBaseLexer);
    SqlBaseParser sqlBaseParser = new SqlBaseParser(tokenStream);

    sqlBaseLexer.removeErrorListeners();
    sqlBaseLexer.addErrorListener(ERROR_LISTENER);

    sqlBaseParser.removeErrorListeners();
    sqlBaseParser.addErrorListener(ERROR_LISTENER);

    Function<SqlBaseParser, ParserRuleContext> parseFunction = SqlBaseParser::statements;
    ParserRuleContext tree;
    try {
      // first, try parsing with potentially faster SLL mode
      sqlBaseParser.getInterpreter().setPredictionMode(PredictionMode.SLL);
      tree = parseFunction.apply(sqlBaseParser);
    } catch (ParseCancellationException ex) {
      // if we fail, parse with LL mode
      tokenStream.reset(); // rewind input stream
      sqlBaseParser.reset();

      sqlBaseParser.getInterpreter().setPredictionMode(PredictionMode.LL);
      tree = parseFunction.apply(sqlBaseParser);
    }

    return tree;
  }