} else {
            resp = negotitate(inputBuf, offset, len);
        }

        if (resp == null) {
            return null;
        }
        return resp.toByteArray();
    }

    private SpnegoToken negotitate(final byte[] inputBuf, final int offset, final int len) throws CIFSException {
        final SpnegoToken spToken = getToken(inputBuf, offset, len);
        byte[] inputToken = null;

        final List<String> docIdList = new ArrayList<>();
        for (final Map<String, Object> inputDoc : docList) {
            final Object idValue = inputDoc.get(fessConfig.getIndexFieldId());
            if (idValue == null) {
                continue;
            }

            final Object configIdValue = inputDoc.get(fessConfig.getIndexFieldConfigId());
            if (configIdValue == null) {
                continue;