private static final String PDF_DATE = "pdf_date";

    /** Regular expression pattern for matching email addresses */
    private static final Pattern EMAIL_ADDRESS_PATTERN =
            Pattern.compile("[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,6}", Pattern.CASE_INSENSITIVE);

    /**
     * Cache for storing resource file modification timestamps to enable cache busting.

     */
    public void test_labelConstantsNamingConvention() throws Exception {
        Field[] fields = FessLabels.class.getDeclaredFields();
        Pattern labelPattern = Pattern.compile("^LABELS_[A-Za-z0-9_]+$");

        for (Field field : fields) {
            if (Modifier.isStatic(field.getModifiers()) && Modifier.isFinal(field.getModifiers()) && Modifier.isPublic(field.getModifiers())

            public Integer getUserCodeMaxLengthAsInteger() {
                return 20;
            }

            @Override
            public String getUserCodePattern() {
                return "[a-zA-Z0-9_]+";
            }
        };

        assertTrue(fessConfig.isValidUserCode("1234567890"));
        assertTrue(fessConfig.isValidUserCode("12345678901234567890"));

        final List<Artifact> list = new ArrayList<>();
        final String repoContent = getRepositoryContent(url);
        final Matcher matcher = Pattern.compile("href=\"[^\"]*(" + artifactType.getId() + "[a-zA-Z0-9\\-]+)/?\"").matcher(repoContent);
        while (matcher.find()) {
            final String name = matcher.group(1);
            if (isExcludedName(artifactType, name)) {
                continue;
            }

                    final String[] v2 = v1[0].split(":", 2);
                    if (v2.length == 2) {
                        return new Tuple3<>(v2[0].trim(), v2[1].trim(), v1[1].replaceAll("[^a-zA-Z0-9_]", StringUtil.EMPTY).trim());
                    }
                }
                return null;
            }).filter(v -> {
                if (v == null) {
                    return false;

            } else if (url.startsWith("file:")) {
                returnUrl = url.replaceFirst("^file:/+", "/");
            } else {
                returnUrl = url.replaceFirst("^[a-zA-Z0-9]*:/+", "");
            }
            final int size = fessConfig.getResponseMaxSitePathLengthAsInteger();
            if (size > 3) {
                return StringUtils.abbreviate(returnUrl, size);
            }