code: @Override
      public void indexHelpModule(HelpModule helpModule) {
          try {
              if (indexTracker.isSame(helpModule)) {
                  return;
              }
              
              unindexHelpModule(helpModule);
              log.info("Indexing help module " + helpModule.getLocalizedId());
              int i = helpModule.getUrl().lastIndexOf('/');
              String pattern = "classpath:" + helpModule.getUrl().substring(0, i + 1) + "*.htm*";
              
              for (Resource resource : appContext.getResources(pattern)) {
                  indexDocument(helpModule, resource);
              }
              
              writer.commit();
              indexTracker.add(helpModule);
          } catch (Exception e) {
              throw MiscUtil.toUnchecked(e);
          }
      }
docs: Index all HTML files within the content of the help module.
  
  @param helpModule Help module to be indexed.