code: public void addFile(String filename, String filePath) {
          int pathIndex = filePathList.indexOf(filePath);
          if (pathIndex == -1) {
              fileNameList.add(filename);
              filePathList.add(filePath);
          }
      }
docs: Adds record of a new file, by filename and path.  The path
  may be relative to a source compilation path.
  
  @param filename the filename to add, unqualified by path
  @param filePath the path for the filename, potentially relative
  to a source compilation path