// print all objects that have one or more FileName parts
// and that are visited during the traversal
Commands {
{{
  void incomingToFileName(TraversalGraph where) {
    FileNameVisitor cV = new FileNameVisitor();
    where.traverse(this, cV);
  }
}}
}

FileNameVisitor {
{{
  void before(Object source, String s, Object target) {
     System.out.println(" object visited " + 
     source.getClass().getName() + " " +
     s + " " + 
     target.getClass().getName());
   }
}}
}