final String docid = DocumentUtil.getValue(docMap, fessConfig.getIndexFieldDocId(), String.class);
        return getImageFilename(docid);
    }

    protected String getImageFilename(final String docid) {
        final StringBuilder buf = new StringBuilder(50);
        for (int i = 0; i < docid.length(); i += splitSize) {
            int hash = docid.substring(i).hashCode() % splitHashSize;

            final Object docIdObj = request.getAttribute(DOC_ID_FIELD);
            if (docIdObj == null) {
                throw new WebApiException(HttpServletResponse.SC_BAD_REQUEST, "docId is empty.");
            }
            final String docId = docIdObj.toString();
            final String queryId = request.getParameter("queryId");

                }
            }
        }
        return StringUtil.EMPTY_STRINGS;
    }

    public OptionalEntity<Map<String, Object>> getDocumentByDocId(final String docId, final String[] fields,
            final OptionalThing<FessUserBean> userBean) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();