* @return The model name.
     */
    public String modelName() {
        return modelName;
    }

    /**
     * Sets the name of the LTR model.
     *
     * @param modelName The model name.
     * @return This query builder.
     */
    public StoredLtrQueryBuilder modelName(final String modelName) {
        this.modelName = Objects.requireNonNull(modelName);
        return this;
    }

    /**

        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String modelName = fessConfig.getLtrModelName();
        if (StringUtil.isBlank(modelName)) {
            return null;
        }
        return new QueryRescorerBuilder(new StoredLtrQueryBuilder().modelName(modelName).params(params))
                .windowSize(fessConfig.getLtrWindowSize());
    }