if (list == null) {
            final String value = getSystemProperty(Constants.DEFAULT_SORT_VALUE_PROPERTY);
            if (StringUtil.isBlank(value)) {
                list = Collections.emptyList();
            } else {
                final Set<String> keySet = new HashSet<>();

## Für FastAPI abstimmen

* <a href="https://www.slant.co/options/34241/~fastapi-review" class="external-link" target="_blank">Stimmen Sie für **FastAPI** auf Slant</a >.
* <a href="https://alternativeto.net/software/fastapi/about/" class="external-link" target="_blank">Stimmen Sie für **FastAPI** auf AlternativeTo</a>.

     */
    @Test
    public void testIsBlank() throws Exception {
        assertEquals("1", true, StringUtil.isBlank(" "));
        assertEquals("2", true, StringUtil.isBlank(""));
        assertEquals("3", false, StringUtil.isBlank("a"));
        assertEquals("4", false, StringUtil.isBlank(" a "));
    }

    /**
     * @throws Exception
     */
    @Test

     *
     * @param key   the key of the feature
     * @param value the value of the feature
     */
    public void addFeature(final String key, final String value) {
        if (StringUtil.isBlank(key) || StringUtil.isBlank(value)) {
            throw new CrawlerSystemException("key or value is null.");
        }

        featureMap.put(key, value);
    }

    /**
     * Adds a property to the extractor.

     * @param u the URL string to extract host from
     * @return the host name, or empty string if URL is blank, or unknown hostname if parsing fails
     */
    default String getHost(final String u) {
        if (StringUtil.isBlank(u)) {
            return StringUtil.EMPTY; // empty
        }

        String url = u;
        final String originalUrl = url;

        int idx = url.indexOf("://");
        if (idx >= 0) {

    /**
     * Updates the LDAP configuration.
     */
    public void updateConfig() {
        isBind = false;
    }

    /**
     * Validates the LDAP connection.
     *
     * @return True if the LDAP connection is valid, otherwise false.
     */
    protected boolean validate() {
        if (!isBind) {

     * @return the OSDD file
     */
    protected File getOsddFile() {
        if (!isOsddLinkEnabled()) {
            logger.debug("OSDD is disabled.");
            return null;
        }
        if (StringUtil.isBlank(osddPath)) {
            logger.info("OSDD file is not found.");
            return null;
        }
        final String path = LaServletContextUtil.getServletContext().getRealPath(osddPath);
        if (path == null) {

     * @return the default groups
     */
    protected static String[] getDefaultGroupsAsArray() {
        final String value = ComponentUtil.getFessConfig().getSystemProperty("oic.default.groups");
        if (StringUtil.isBlank(value)) {
            return StringUtil.EMPTY_STRINGS;
        }
        return split(value, ",").get(stream -> stream.filter(StringUtil::isNotBlank).map(String::trim).toArray(n -> new String[n]));
    }

    /**

                }
            }

            String r = realm;
            if (StringUtil.isBlank(realm)) {
                r = AuthScope.ANY_REALM;
            }

            String s = scheme;
            if (StringUtil.isBlank(scheme) || Constants.NTLM.equals(scheme)) {
                s = AuthScope.ANY_SCHEME;
            }

                        final String userCode = userInfoHelper.getUserCode();

                        if (StringUtil.isBlank(userCode)) {
                            throw new WebApiException(HttpServletResponse.SC_BAD_REQUEST, "No user session.");
                        }
                        if (StringUtil.isBlank(favoriteUrl)) {
                            throw new WebApiException(HttpServletResponse.SC_BAD_REQUEST, "URL is null.");