if (text == null || text.isEmpty()) {
                return Collections.emptyList();
            }

            List<String> readings = new ArrayList<>();
            int limit = Math.min(langs.length, getMaxReadingNum());

            for (int i = 0; i < limit; i++) {
                readings.add(text.toUpperCase() + "_" + langs[i]);
            }

            return readings;
        }

    /** Cache for XPathAPI instances to improve performance. */
    protected LoadingCache<String, XPathAPI> xpathAPICache;

    /** Cache duration in minutes for XPathAPI instances. */
    protected long cacheDuration = 10; // min

    /**
     * Creates a new HtmlXpathExtractor instance.
     */
    public HtmlXpathExtractor() {
        super();
    }

    /**
     * Initializes the XPathAPI cache with a specified cache duration.

    /**
     * The XPathAPI cache.
     */
    protected LoadingCache<String, XPathAPI> xpathAPICache;

    /**
     * The cache duration in minutes.
     */
    protected long cacheDuration = 10; // min

    /**
     * Constructs a new instance of {@code XmlTransformer}.
     * This constructor initializes the transformer with default settings.
     */
    public XmlTransformer() {
        super();
    }