Helping to find the usefulness of a proposal

[Mark Mahieu]

Hi Jon,
Invoking the parser directly seemed like the quickest way of grabbing some
figures at the time, but you (and Michael) are quite right of course.

The main point I was trying to get across was there are easily approachable
ways that people can attempt to do some of the analysis Stephen mentioned,
without ripping components out of Netbeans etc to do it, great though they
may be.

But I shouldn't be spreading my bad habits around with abandon like that,
quick hack or not :)

My apologies.

Mark


2009/4/2 Jonathan Gibbons <Jonathan.Gibbons at sun.com>

> For all this sort of analysis, you'd do better to use the combination of
> javac's
> annotation processing framework and the javac Tree API, than to use direct
> access into private javac API.
>
> Annotation processing isn't just for processing annotations ;-)  You can
> write
> a processor that will be called on all types, and you can bridge from the
> processing world (javax.lang.model.*) to the java Tree API
> (com.sun.source.*)
> using com.sun.source.util.Trees.   This allows you to write utilities to
> analyze ASTs without requiring the use of any javac internal API.
>
> -- Jon
>
>
>
>
> Mark Mahieu wrote:
>
>> Wow.
>>
>> http://www.geekherocomic.com/comics-highres/2009-02-25-coding-overkill.png
>>
>>
>> Here are the important bits from my quick hack.  Took under half an hour
>> to
>> get it finding cases where Auto-assignment Parameters would and wouldn't
>> work across large source trees.
>>
>> Of course, javac makes much more than parsing available if you need it...
>>
>>
>>
>> import com.sun.tools.javac.file.JavacFileManager;
>> import com.sun.tools.javac.parser.JavacParser;
>> import com.sun.tools.javac.parser.ParserFactory;
>> import com.sun.tools.javac.tree.TreeScanner;
>> import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
>> import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
>> import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
>> import com.sun.tools.javac.util.Context;
>> import com.sun.tools.javac.util.List;
>>
>> ...
>>
>> // create a TreeScanner to do your analysis
>> TreeScanner scanner = new TreeScanner() {
>>
>> @Override
>> public void visitMethodDef(JCMethodDecl tree) {
>>  // look at a method's parameters
>> for (List<JCVariableDecl> l = params; l.nonEmpty(); l = l.tail) {
>> JCVariableDecl param = l.head;
>>  // examine param or whatever
>> }
>>  // continue recursively scanning the method body etc
>> super.visitMethodDef(tree);
>> }
>> };
>>
>> ...
>>
>> Context context = new Context();
>> JavacFileManager.preRegister(context);
>> ParserFactory factory = ParserFactory.instance(context);
>>
>> String sourceCode = readSourceFromFile(...);
>>
>> JavacParser parser = (JavacParser) factory.newParser(sourceCode, false,
>> false, false);
>> JCCompilationUnit cu = parser.parseCompilationUnit();
>>
>> // do your analysis
>> scanner.scan(cu);
>>
>>
>>
>
>