code: public void visitFiles(final FileVisitor visitor) {
      final Project p = getProject();
      if (p == null) {
        throw new java.lang.IllegalStateException("project must be set before this call");
      }
      if (isReference()) {
        ((ProcessorDef) getCheckedRef(ProcessorDef.class, "ProcessorDef")).visitFiles(visitor);
      }
      //
      // if this processor extends another,
      // visit its files first
      //
      final ProcessorDef extendsDef = getExtends();
      if (extendsDef != null) {
        extendsDef.visitFiles(visitor);
      }
  
      for (int i = 0; i < this.srcSets.size(); i++) {
        final ConditionalFileSet srcSet = (ConditionalFileSet) this.srcSets.elementAt(i);
        if (srcSet.isActive()) {
          // Find matching source files
          final DirectoryScanner scanner = srcSet.getDirectoryScanner(p);
          // Check each source file - see if it needs compilation
          final String[] fileNames = scanner.getIncludedFiles();
          final File parentDir = scanner.getBasedir();
          for (final String currentFile : fileNames) {
            visitor.visit(parentDir, currentFile);
          }
        }
      }
    }
docs: This method calls the FileVistor's visit function for every file in the
  processors definition
  
  @param visitor
  object whose visit method is called for every file