@Override
    public void endDocument() throws SAXException {
        super.endDocument();
        List<String> numbers = CleanPhoneText.extractPhoneNumbers(stringBuilder.toString());
        for (String number : numbers) {
            metadata.add(PHONE_NUMBERS, number);
        }
    }
This method is called whenever the Parser is done parsing the file. So,
we check the output for any phone numbers.
tika-core/src/main/java/org/apache/tika/sax/PhoneExtractingContentHandler.java