final FessXpathTransformer transformer = new FessXpathTransformer();
        final Map<String, String> params = Maps.of("foo", "cache", "bar", "overwrite", "baz", "cache|overwrite");
        FieldConfigs fieldConfigs = new FieldConfigs(params);
        final Map<String, Object> dataMap = Map.of(//
                "foo", new String[] { "aaa", "bbb" }, //
                "bar", new String[] { "ccc", "ddd" }, //