TypeCalculation.java 文件源码

private static ParserRuleContext parseTypeCalculation(String calculation)
{
    TypeCalculationLexer lexer = new TypeCalculationLexer(new CaseInsensitiveStream(new ANTLRInputStream(calculation)));
    CommonTokenStream tokenStream = new CommonTokenStream(lexer);
    TypeCalculationParser parser = new TypeCalculationParser(tokenStream);

    lexer.removeErrorListeners();
    lexer.addErrorListener(ERROR_LISTENER);

    parser.removeErrorListeners();
    parser.addErrorListener(ERROR_LISTENER);

    ParserRuleContext tree;
    try {
        // first, try parsing with potentially faster SLL mode
        parser.getInterpreter().setPredictionMode(PredictionMode.SLL);
        tree = parser.typeCalculation();
    }
    catch (ParseCancellationException ex) {
        // if we fail, parse with LL mode
        tokenStream.reset(); // rewind input stream
        parser.reset();

        parser.getInterpreter().setPredictionMode(PredictionMode.LL);
        tree = parser.typeCalculation();
    }
    return tree;
}