docs: private NamingEnumeration search(String base, String filter,
                                       String[] returnAttrs)
          throws NamingException {
  
          SearchControls constraints = new SearchControls();
          constraints.setSearchScope(SearchControls.SUBTREE_SCOPE);
          constraints.setReturningAttributes(returnAttrs);
  
          // search the directory based on base, filter, and contraints
          //logger.debug("searching, base: " + base + " using filter: " + filter);
          DirContext dirContext = context();
          // get established jndi connection
          return dirContext.search(base, filter, constraints);
      }