final String url = DocumentUtil.getValue(doc, fessConfig.getIndexFieldThumbnail(), String.class);
        if (StringUtil.isBlank(form.queryId) || StringUtil.isBlank(url) || !thumbnailSupport) {
            // 404
            throw responseManager.new404("Thumbnail for " + form.docId + " is not found.");
        }

    FessConfig getFessConfig();

    Logger getLogger();

    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) {

    protected String denyPrefix = "(deny)";

    @Resource
    protected SystemHelper systemHelper;

    public String encode(final String value) {
        if (StringUtil.isBlank(value)) {
            return null;
        }

        String permission = value.trim();
        String lower = permission.toLowerCase(Locale.ROOT);
        final String aclPrefix;

     */
    @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

    }

    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) {

    }

    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;
            }

            }
            if (entity.getTerm().startsWith(regexPrefix)) {
                final String regex = entity.getTerm().substring(regexPrefix.length());
                if (StringUtil.isBlank(regex)) {
                    logger.warn("Unknown regex pattern: {}", entity.getTerm());
                } else {
                    pair.getSecond().add(new Pair<>(Pattern.compile(regex), entity.getContent()));

                    logger.debug("add {} field", lf);
                }
            }
        }
    }

    protected String detectLanguage(final String text) {
        if (StringUtil.isBlank(text)) {
            return null;
        }
        final String target = getDetectText(text);
        final LanguageResult result = detector.detect(target);
        if (logger.isDebugEnabled()) {

        ComponentUtil.getThumbnailManager().add(this);
    }

    public void addCondition(final String key, final String regex) {
        final String value = conditionMap.get(key);
        if (StringUtil.isBlank(value)) {
            conditionMap.put(key, regex);
        } else {
            conditionMap.put(key, value + "|" + regex);
        }
    }

    @Override