docs: @Override public TopLevelItem getItem(String name) throws AccessDeniedException {
          if (name==null)    return null;
          TopLevelItem item = items.get(name);
          if (item==null)
              return null;
          if (!item.hasPermission(Item.READ)) {
              if (item.hasPermission(Item.DISCOVER)) {
                  throw new AccessDeniedException("Please login to access job " + name);
              }
              return null;
          }
          return item;
      }