private void extractMultiOSPDEmbeddedFiles(String displayName, String annotationType,
                                               PDComplexFileSpecification spec,
                                               AttributesImpl attributes)
            throws IOException, SAXException, TikaException {

        if (spec == null) {
            return;
        }

        //current strategy is to pull all, not just first non-null
        extractPDEmbeddedFile(displayName, annotationType, spec, spec.getFile(),
                spec.getEmbeddedFile(), attributes);
        extractPDEmbeddedFile(displayName, annotationType, spec, spec.getFileMac(),
                spec.getEmbeddedFileMac(), attributes);
        extractPDEmbeddedFile(displayName, annotationType, spec, spec.getFileDos(),
                spec.getEmbeddedFileDos(), attributes);
        extractPDEmbeddedFile(displayName, annotationType, spec, spec.getFileUnix(),
                spec.getEmbeddedFileUnix(), attributes);

        //Check for /Thumb (thumbnail image);
        // /CI (collection item) adobe specific, can have /adobe:DisplayName and a summary
    }
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