code: @RequestMapping("/source")
      public final String source(
              @RequestParam(value = "id",
                  required = false,
                  defaultValue = "S0") final String idString,
              @RequestParam(value = "db",
                  required = false,
                  defaultValue = "schoeller") final String dbName,
              final Model model) {
          logger.debug("Entering source");
  
          final Root root = fetchRoot(dbName);
  
          final RenderingContext context = createRenderingContext();
          final Source source = (Source) root.find(idString);
          if (source == null) {
              throw new SourceNotFoundException(
                      "Source " + idString + " not found", idString, dbName,
                      context);
          }
  
          final GedRenderer<?> sourceRenderer = new GedRendererFactory()
                  .create(source, context);
  
          model.addAttribute("filename", gedbrowserHome + "/" + dbName + ".ged");
          model.addAttribute("sourceString", source.getString());
          model.addAttribute("model", sourceRenderer);
          model.addAttribute("appInfo", appInfo);
          logger.debug("Exiting source");
          return "source";
      }
docs: Connects HTML template file with data for the source page.
  
  @param idString id URL argument.
  @param dbName name of database for the lookup.
  @param model Spring connection between the data model wrapper.
  @return a string identifying which HTML template to use.