{"id":482,"date":"2019-01-03T09:01:43","date_gmt":"2019-01-02T23:01:43","guid":{"rendered":"https:\/\/www.docx4java.org\/blog\/?p=482"},"modified":"2019-01-03T09:38:30","modified_gmt":"2019-01-02T23:38:30","slug":"opendope-and-xpath-2-03-0","status":"publish","type":"post","link":"https:\/\/www.docx4java.org\/blog\/2019\/01\/opendope-and-xpath-2-03-0\/","title":{"rendered":"OpenDoPE and XPath 2.0\/3.0"},"content":{"rendered":"

Docx4j generally uses Apache XPath (org.apache.xpath),\u00a0from the Xalan 2.7.2 jar.\u00a0 (docx4j uses Xalan plus Xalan-specific extension functions for XSLT in\u00a0various places including HTML export and OpenDoPE processing).<\/p>\n

There are 2 main places where docx4j uses XPath:<\/p>\n

    \n
  1. JaxbXmlPartXPathAware<\/strong> contains method getJAXBNodesViaXPath<\/strong>, which – thanks to JAXB’s concept of a binder<\/strong> – you can use to select objects (say P objects) in your MainDocumentPart<\/li>\n
  2. OpenDoPE content control data binding<\/strong>: XPath is central to content control data binding (binding document content to XML data via XPath).<\/li>\n<\/ol>\n

    XPath 2.0 became a W3C Rec in 2007;\u00a0 XPath 3.0\u00a0became a W3C Rec in 2014.<\/p>\n

    Sadly, Apache XPath has languished at XPath 1.0 level:\u00a0https:\/\/intellectualcramps.wordpress.com\/2009\/01\/12\/xerces-getting-xpath-2-0-support\/<\/a> and http:\/\/apache-xml-project.6118.n7.nabble.com\/XSLT-2-0-td20898.html<\/a> <\/p>\n

    Saxon, in contrast, has supported XPath 2.0 for ages, and also supports 3.1.<\/p>\n

    In docx4j 6.1.0 we made it easy for you to try\u00a0Saxon for case 1 (JaxbXmlPartXPathAware\u00a0getJAXBNodesViaXPath):<\/p>\n

    Step 1: add Saxon to your classpath, for example (Maven):<\/p>\n

    \r\n<dependency>\r\n  <groupId>net.sf.saxon<\/groupId>\r\n  <artifactId>Saxon-HE<\/artifactId>\r\n  <version>9.9.0-2<\/version>\r\n<\/dependency>\r\n<\/pre>\n
    Step 2: add the following early in your code:<\/p>\n
    \r\nXPathFactoryUtil.setxPathFactory(new net.sf.saxon.xpath.XPathFactoryImpl())\r\n<\/pre>\n
    In docx4j 6.1.0,\u00a0this only affects\u00a0case 1.\u00a0\u00a0OpenDoPE content control data binding would still use Apache XPath.<\/p>\n
    In docx4j 8.0.0,\u00a0Saxon would also be used for\u00a0OpenDoPE content control data binding.<\/p>\n
    An example: date comparison<\/h2>\n
    You can add\u00a0an OpenDoPE conditional content control, in which the content is inserted only if XPath “xs:date(\/invoice\/date) > xs:date(‘2018-12-31’)<\/strong>” is true.\u00a0 (date comparison is harder in XPath 1.0:\u00a0https:\/\/stackoverflow.com\/questions\/4347320\/xpath-dates-comparison )<\/p>\n
    For this to work, you need the prefix mapping\u00a0xmlns:xs=’http:\/\/www.w3.org\/2001\/XMLSchema’, so your XPath in the OpenDoPE XPaths path would look something like:<\/p>\n
    \r\n<xpath id="dateGt">\r\n  <dataBinding xpath="xs:date(\/invoice\/date) &amp;gt; xs:date('2018-12-31')" \r\n prefixMappings="xmlns:xs='http:\/\/www.w3.org\/2001\/XMLSchema'" \r\n storeItemID="{8B049945-9DFE-4726-9DE9-CF5691E53858}"\/>\r\n<\/xpath>\r\n<\/pre>\n
    (for now, you need to manually edit the zipped docx to add that; I’ll update the authoring tools to do it in due course)<\/p>\n
    You can try this example right away:<\/p>\n