docs: private void setCurrentName(final String original_value, 
        final String extracted_value) {
  
      // now parse and set the display name. If the formatter is empty, we just 
      // set it to the parsed value and exit
      String format = rule.getDisplayFormat();
      if (format == null || format.isEmpty()) {
        current_branch.setDisplayName(extracted_value);
        return;
      }
      
      if (format.contains("{ovalue}")) {
        format = format.replace("{ovalue}", original_value);
      }
      if (format.contains("{value}")) {
        format = format.replace("{value}", extracted_value);
      }
      if (format.contains("{tsuid}")) {
        format = format.replace("{tsuid}", meta.getTSUID());
      }
      if (format.contains("{tag_name}")) {
        final TreeRuleType type = rule.getType();
        if (type == TreeRuleType.TAGK) {
          format = format.replace("{tag_name}", rule.getField());
        } else if (type == TreeRuleType.METRIC_CUSTOM ||
            type == TreeRuleType.TAGK_CUSTOM ||
            type == TreeRuleType.TAGV_CUSTOM) {
          format = format.replace("{tag_name}", rule.getCustomField());
        } else {
          // we can't match the {tag_name} token since the rule type is invalid
          // so we'll just blank it
          format = format.replace("{tag_name}", "");
          LOG.warn("Display rule " + rule + 
            " was of the wrong type to match on {tag_name}");
          if (test_messages != null) {
            test_messages.add("Display rule " + rule + 
                " was of the wrong type to match on {tag_name}");
          }
        }
      }
      current_branch.setDisplayName(format);
    }