Generating XML content with SAX including schema reference

Question

Hi all, XML newbie question here.
I'm trying to generate an XML document from a certain file format using SAX, but I can't figure out how to get the generated XML document to include a schema reference.
Here's the code, it's taken from posts on this forum, so it should be familiar:
StreamResult streamResult = new StreamResult(out);
        SAXTransformerFactory tf = (SAXTransformerFactory) SAXTransformerFactory.newInstance();
        try {
            TransformerHandler hd = tf.newTransformerHandler();
            Transformer serializer = hd.getTransformer();
            serializer.setOutputProperty(OutputKeys.ENCODING, "ISO-8859-1");
            serializer.setOutputProperty(OutputKeys.INDENT, "yes");
            hd.setResult(streamResult);
            hd.startDocument();
            AttributesImpl atts = new AttributesImpl();
            hd.startElement("http://maul.ddm.apm.bpm.eds.com", "DTR_XML", "DTR_XML", atts);
            hd.endElement("http://maul.ddm.apm.bpm.eds.com", "DTR_XML", "DTR_XML");
            hd.endDocument();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (TransformerConfigurationException e) {
            e.printStackTrace();
        }Here's the output I get:
<?xml version="1.0" encoding="ISO-8859-1"?>
<DTR_XML/>
And I'm looking for output like this (I think - basically I have this dtr_xml.xsd located at the root web directory on http://maul.ddm.apm.bpm.eds.com and I want the generated XML file to reference that schema for validation when parsing):
<?xml version="1.0" encoding="ISO-8859-1"?>
<DTR_XML xmlns="http://maul.ddm.apm.bpm.eds.com"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maul.ddm.apm.bpm.eds.com dtr_xml.xsd"/>

Answer 1

Yes, you've led me along the right track with the attributes stuff. Here's what I've got right now...
StreamResult streamResult = new StreamResult(out);
        SAXTransformerFactory tf = (SAXTransformerFactory) SAXTransformerFactory.newInstance();
        try {
            TransformerHandler hd = tf.newTransformerHandler();
            Transformer serializer = hd.getTransformer();
            serializer.setOutputProperty(OutputKeys.ENCODING, "ISO-8859-1");
            serializer.setOutputProperty(OutputKeys.INDENT, "yes");
            hd.setResult(streamResult);
            hd.startDocument();
            AttributesImpl atts = new AttributesImpl();
            atts.addAttribute("", "xmlns", "xmlns", "CDATA", "http://maul.ddm.apm.bpm.eds.com");
            atts.addAttribute("", "xsi", "xmlns:xsi", "CDATA", "http://www.w3.org/2001/XMLSchema-instance");
            atts.addAttribute("", "schemaLocation", "xsi:schemaLocation", "CDATA", "http://maul.ddm.apm.bpm.eds.com dtr_xml.xsd");
            hd.startElement("", "DTR_XML", "DTR_XML", atts);
            hd.endElement("", "DTR_XML", "DTR_XML");
            hd.endDocument();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (TransformerConfigurationException e) {
            e.printStackTrace();
        }This produces the output I wanted earlier...
As for the org.xml.sax.helpers.NamespaceSupport, I can't seem to find any documentation on using it anywhere, and the javadoc is cryptic to me. Maybe it's used internally in SAX for tracking namespaces or something like that.
Another interesting thing to me is that if I use the code you gave:
atts.addAttribute("http://www.w3.org/2001/XMLSchema-instance", "schemaLocation",
     "xsi:schemaLocation", "CDATA", "http://maul.ddm.apm.bpm.eds.com dtr_xml.xsd");I don't see "http://www.w3.org/2001/XMLSchema-instance" anywhere in the output. Is SAX ignoring the namespace uri argument? It appears so. The javadoc states that the uri argument is "The Namespace URI, or the empty string if none is available or Namespace processing is not being performed." It would appear that Namespace processing is not being done... but I don't know how to turn it on.