Is it somehow possible to use this javacc jar to parse a jjt and jj file

I want to construct some tests depending on the tokens used in a specific rule of my grammar.

void myrule() : {} {
<K_MYKEYWORD1>
| <K_MYKEYWORD2>
}

So I have a jjt file and need to transform this in a jj file and then parse this and get the AST - node tree, to traverse it.

My first attempt was this:

var parser = new JJTreeParser(
                Files.newInputStream(Paths.get("src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt"))
) {
    public ASTGrammar getRoot() {
        return (ASTGrammar)jjtree.rootNode());
    }
};
parser.javacc_input();

new JavaCodeGenerator().visit(parser.getRoot(), io);

But I have to fight method and class visibility issues:

IO is only package private, ASTGrammer.generate is package private as well.

[manticore-projects]

Or in other words: What would be the best (e.g. simplest and most robust) to extract the actual Tokens from a jj Grammar File, without running JTREE first and also considering Composite Tokens.

[manticore-projects]

For reference, below is the code which finally returns all Keywords from a Grammar:

    private static void addTokenImage(TreeSet<String> allKeywords, RStringLiteral literal) {
        if (CHARSET_ENCODER.canEncode(literal.image) && literal.image.matches("[A-Za-z]+")) {
            allKeywords.add(literal.image);
        }
    }

    @SuppressWarnings({"PMD.EmptyIfStmt", "PMD.CyclomaticComplexity"})
    private static void addTokenImage(TreeSet<String> allKeywords, Object o) throws Exception {
        if (o instanceof RStringLiteral) {
            RStringLiteral literal = (RStringLiteral) o;
            addTokenImage(allKeywords, literal);
        } else  if (o instanceof RChoice) {
            RChoice choice = (RChoice) o;
            addTokenImage(allKeywords, choice);
        } else if (o instanceof RSequence) {
            RSequence sequence1 = (RSequence) o;
            addTokenImage(allKeywords, sequence1);
        } else if (o  instanceof ROneOrMore) {
            ROneOrMore oneOrMore = (ROneOrMore) o ;
            addTokenImage(allKeywords, oneOrMore);
        } else if (o  instanceof RZeroOrMore) {
            RZeroOrMore zeroOrMore = (RZeroOrMore) o ;
            addTokenImage(allKeywords, zeroOrMore);
        } else if (o  instanceof RZeroOrOne) {
            RZeroOrOne zeroOrOne = (RZeroOrOne) o ;
            addTokenImage(allKeywords, zeroOrOne);
        }  else if (o  instanceof RJustName) {
            RJustName zeroOrOne = (RJustName) o ;
            addTokenImage(allKeywords, zeroOrOne);
        } else if (o  instanceof RCharacterList) {
           // do nothing, we are not interested in those
        } else {
            throw new InvalidClassException("Unknown Type: " + o.getClass().getName() + " " + o.toString());
        }
    }

    private static void addTokenImage(TreeSet<String> allKeywords, RSequence sequence) throws Exception {
        for (Object o: sequence.units) {
            addTokenImage(allKeywords, o);
        }
    }

    private static void addTokenImage(TreeSet<String> allKeywords, ROneOrMore oneOrMore) {
        for (Token token: oneOrMore.lhsTokens) {
            if (CHARSET_ENCODER.canEncode(token.image)) {
                allKeywords.add(token.image);
            }
        }
    }

    private static void addTokenImage(TreeSet<String> allKeywords, RZeroOrMore oneOrMore) {
        for (Token token: oneOrMore.lhsTokens) {
            if (CHARSET_ENCODER.canEncode(token.image)) {
                allKeywords.add(token.image);
            }
        }
    }

    private static void addTokenImage(TreeSet<String> allKeywords, RZeroOrOne oneOrMore) {
        for (Token token: oneOrMore.lhsTokens) {
            if (CHARSET_ENCODER.canEncode(token.image)) {
                allKeywords.add(token.image);
            }
        }
    }

    private static void addTokenImage(TreeSet<String> allKeywords, RJustName oneOrMore) {
        for (Token token: oneOrMore.lhsTokens) {
            if (CHARSET_ENCODER.canEncode(token.image)) {
                allKeywords.add(token.image);
            }
        }
    }

    private static void addTokenImage(TreeSet<String> allKeywords, RChoice choice) throws  Exception {
        for (Object o: choice.getChoices()) {
            addTokenImage(allKeywords, o);
        }
    }

    public static TreeSet<String> getAllKeywordsUsingJavaCC(File file) throws Exception {
        TreeSet<String> allKeywords = new TreeSet<>();

        Path jjtGrammar = file.toPath();
        Path jjGrammarOutputDir = Files.createTempDirectory("jjgrammer");

        new JJTree().main(new String[]{
                "-JDK_VERSION=1.8",
                "-OUTPUT_DIRECTORY=" + jjGrammarOutputDir.toString(),
                jjtGrammar.toString()
        });
        Path jjGrammarFile = jjGrammarOutputDir.resolve("JSqlParserCC.jj");

        JavaCCParser parser = new JavaCCParser(new java.io.FileInputStream(jjGrammarFile.toFile()));
        parser.javacc_input();

        // needed for filling JavaCCGlobals
        Semanticize.start();

        // read all the Token and get the String image
        for (Map.Entry<Integer, RegularExpression> item : JavaCCGlobals.rexps_of_tokens.entrySet()) {
            addTokenImage(allKeywords, item.getValue());
        }

        //clean up
        if (jjGrammarOutputDir.toFile().exists()) {
            jjGrammarOutputDir.toFile().delete();
        }

        return allKeywords;
    }

We can close this issue.