private void parseEmbedded(DirectoryEntry dir, XHTMLContentHandler xhtml, Metadata metadata,
                               boolean outputHtml)
            throws IOException, SAXException {
        if (!embeddedDocumentUtil.shouldParseEmbedded(metadata)) {
            return;
        }
        try (TikaInputStream tis = TikaInputStream.get(new byte[0])) {
            tis.setOpenContainer(dir);
            if (dir.getStorageClsid() != null) {
                metadata.set(Office.EMBEDDED_STORAGE_CLASS_ID,
                        dir.getStorageClsid().toString());
            }
            embeddedDocumentUtil.parseEmbedded(tis, xhtml, metadata, outputHtml);
        }
    }
Handle an office document that's embedded at the POIFS level
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-microsoft-module/src/main/java/org/apache/tika/parser/microsoft/AbstractPOIFSExtractor.java