[antlr-interest] Performance question.

[Seref Arikan]

This is an interesting question that I'd also be very glad to see an answer.

Best Regards
Seref

Alex Shneyderman wrote:
> I need to  parse java files to augment them with some code. So, I went
> to antlr's site downlaoded the availble java grammar and generted
> myself a parser.
>
> Now, I run the parser on one of the projects - it has approximately
> 1000 java files. To parse each file I use the following code:
>
> try {
>  Java15Lexer lexer = new Java15Lexer(new FileInputStream(file));
>  Java15Parser parser = new Java15Parser(lexer);
>  parser.compilationUnit();
> } catch (Throwable t) {
>  System.out.println ("Can't parse: " + file.getAbsolutePath() + "; "
> + t.getMessage());
> }
>
> Parsing of this many files takes about 41 sec.
>
> Then I came across ecj (eclipse compiler that is distributed
> separately now) that has parser as part of it. So I run the parser
> only part on the same source set and the turn-around there is about 3
> sec. I am not sure of the quality of the AST it generated but I can
> definitely navigate typpe declarations, fields, methods and statements
> within the methods.
>
> I am wondering whether I am doing anything wrong while runing ANTLR
> (2.6.7 version).
> Any suggestions to improve performance?
>