this.index = index;
            String titleValue = toStringOrNull(doc.get("title"));
            if (titleValue == null || titleValue.isEmpty()) {
                titleValue = toStringOrNull(doc.get("content_title"));
            }
            this.title = titleValue;
            this.url = toStringOrNull(doc.get("url"));
            this.docId = toStringOrNull(doc.get("doc_id"));