docs: public void parse(final String filename, final File dir) {
          filePath = stripFragment(filename);
          dirPath = dir;
          try {
              final File f = new File(dir, filePath);
              reader.setErrorHandler(new DITAOTXMLErrorHandler(f.getAbsolutePath(), logger));
              logger.info("Processing " + f.getAbsolutePath());
              reader.parse(f.toURI().toString());
          } catch (final RuntimeException e) {
              throw e;
          } catch (final Exception e) {
              throw new RuntimeException("Failed to parse " + filename + ": " + e.getMessage(), e);
          }
      }