JAXB Namespace issue - namespaces

Question

This question is for Mr.Blaise Doughan on JAXB Namespace
I have situation where,
Have a sample.xsd (old version - no namespace ). Generated JAXB classes using the XJC for the same XSD file. I got one example that uses the JAXB classes to unmarshal the XML data file , based on the XSD.
The sample.xsd file got changed (new version - added namespace). Again generated JAXB classes using the XJC for the new XSD file. The Example is updated so that it can now work for new XSD file
Now I got a situation , where iam getting XML data file based on old XSD and I would like to use the updated example file to unmarshal the old XML data.
One solution I could see , generating two object factory one with namespace and one without namespace. Can we do that? if so I can use the appropriate Object factory based on the my XML data I get.
Or would like to know , how can I generate JAXB classes for both XSD files , but XJC is not generating , it shows error - No changes detected in schema or binding files - skipping source generation.
Can I create a wrapper over the new Object Factory so that it can handle both ?
Please do provide me with some solution so that I can unmarshal the old file with new JAXB classes. Can

Answer 1

Apply a Namespace
In the case where the input XML does not have a namespace you can leverage a SAX XMLFilter to apply a namespace.
import org.xml.sax.*;
import org.xml.sax.helpers.XMLFilterImpl;
public class NamespaceFilter extends XMLFilterImpl {
private static final String NAMESPACE = "http://www.example.com/customer";
#Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
super.endElement(NAMESPACE, localName, qName);
}
#Override
public void startElement(String uri, String localName, String qName,
Attributes atts) throws SAXException {
super.startElement(NAMESPACE, localName, qName, atts);
}
}
Do the Unmarshal
The unmarshalling is done leveraging JAXB's UnmarshallerHandler as the ContentHandler
import javax.xml.bind.*;
import javax.xml.parsers.*;
import org.xml.sax.*;
public class Demo {
public static void main(String[] args) throws Exception {
// Create the JAXBContext
JAXBContext jc = JAXBContext.newInstance(Customer.class);
// Create the XMLFilter
XMLFilter filter = new NamespaceFilter();
// Set the parent XMLReader on the XMLFilter
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
filter.setParent(xr);
// Set UnmarshallerHandler as ContentHandler on XMLFilter
Unmarshaller unmarshaller = jc.createUnmarshaller();
UnmarshallerHandler unmarshallerHandler = unmarshaller
.getUnmarshallerHandler();
filter.setContentHandler(unmarshallerHandler);
// Parse the XML
InputSource xml = new InputSource("src/blog/namespace/sax/input.xml");
filter.parse(xml);
Customer customer = (Customer) unmarshallerHandler.getResult();
// Marshal the Customer object back to XML
Marshaller marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(customer, System.out);
}
}
For More Information
http://blog.bdoughan.com/2012/11/applying-namespace-during-jaxb-unmarshal.html