private static void addNonNullAttribute(String name, String value, AttributesImpl attributes) {
        if (name == null || value == null) {
            return;
        }
        attributes.addAttribute("", name, name, "CDATA", value);
    }
Format used for signature dates
TODO Make this thread-safe
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-pdf-module/src/main/java/org/apache/tika/parser/pdf/AbstractPDF2XHTML.java