if (StringUtil.isBlank(pattern)) {
                return null;
            }
            final Matcher matcher = Pattern.compile(pattern, Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE).matcher(value);
            final StringBuffer buf = new StringBuffer(value.length() + 100);
            while (matcher.find()) {

    private static final String PDF_DATE = "pdf_date";

    private static final Pattern EMAIL_ADDRESS_PATTERN =
            Pattern.compile("[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,6}", Pattern.CASE_INSENSITIVE);

    private static LoadingCache<String, Long> resourceHashCache =
            CacheBuilder.newBuilder().maximumSize(1000).expireAfterWrite(10, TimeUnit.MINUTES).build(new CacheLoader<String, Long>() {