return fessConfig.getRoleSearchGroupPrefix();
            }
        }
        return null;
    }

    /**
     * Escapes special characters in an LDAP search filter to prevent injection attacks.
     *
     * @param filter the LDAP search filter to escape
     * @return the escaped filter string
     */
    protected String escapeLDAPSearchFilter(String filter) {

    /**
     * Default constructor.
     */
    public FessXpathTransformer() {
        super();
    }

    /**
     * Initializes the transformer after dependency injection.
     * Sets up the Fess configuration and data serializer components.
     */
    @PostConstruct
    public void init() {
        if (logger.isDebugEnabled()) {