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*
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import java.util.Enumeration;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.UnmarshallerHandler;
import org.xml.sax.Attributes;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.helpers.NamespaceSupport;
import org.xml.sax.helpers.XMLFilterImpl;
import primer.PurchaseOrderType;
/*
* @(#)$Id: Splitter.java,v 1.1 2007-12-05 00:49:34 kohsuke Exp $
*/
/**
* This object implements XMLFilter and monitors the incoming SAX
* events. Once it hits a purchaseOrder element, it creates a new
* unmarshaller and unmarshals one purchase order.
*
* <p>
* Once finished unmarshalling it, we will process it, then move
* on to the next purchase order.
*/
public class Splitter extends XMLFilterImpl {
public Splitter( JAXBContext context ) {
this.context = context;
}
/**
* We will create unmarshallers from this context.
*/
private final JAXBContext context;
public void startElement(String namespaceURI, String localName, String qName, Attributes atts)
throws SAXException {
if( depth!= 0 ) {
// we are in the middle of forwarding events.
// continue to do so.
depth++;
super.startElement(namespaceURI, localName, qName, atts);
return;
}
if( namespaceURI.equals("") && localName.equals("purchaseOrder") ) {
// start a new unmarshaller
Unmarshaller unmarshaller;
try {
unmarshaller = context.createUnmarshaller();
} catch( JAXBException e ) {
// there's no way to recover from this error.
// we will abort the processing.
throw new SAXException(e);
}
unmarshallerHandler = unmarshaller.getUnmarshallerHandler();
// set it as the content handler so that it will receive
// SAX events from now on.
setContentHandler(unmarshallerHandler);
// fire SAX events to emulate the start of a new document.
unmarshallerHandler.startDocument();
unmarshallerHandler.setDocumentLocator(locator);
Enumeration e = namespaces.getPrefixes();
while( e.hasMoreElements() ) {
String prefix = (String)e.nextElement();
String uri = namespaces.getURI(prefix);
unmarshallerHandler.startPrefixMapping(prefix,uri);
}
String defaultURI = namespaces.getURI("");
if( defaultURI!=null )
unmarshallerHandler.startPrefixMapping("",defaultURI);
super.startElement(namespaceURI, localName, qName, atts);
// count the depth of elements and we will know when to stop.
depth=1;
}
}
public void endElement(String namespaceURI, String localName, String qName) throws SAXException {
// forward this event
super.endElement(namespaceURI, localName, qName);
if( depth!=0 ) {
depth--;
if( depth==0 ) {
// just finished sending one chunk.
// emulate the end of a document.
Enumeration e = namespaces.getPrefixes();
while( e.hasMoreElements() ) {
String prefix = (String)e.nextElement();
unmarshallerHandler.endPrefixMapping(prefix);
}
String defaultURI = namespaces.getURI("");
if( defaultURI!=null )
unmarshallerHandler.endPrefixMapping("");
unmarshallerHandler.endDocument();
// stop forwarding events by setting a dummy handler.
// XMLFilter doesn't accept null, so we have to give it something,
// hence a DefaultHandler, which does nothing.
setContentHandler(new DefaultHandler());
// then retrieve the fully unmarshalled object
try {
JAXBElement<PurchaseOrderType> result =
(JAXBElement<PurchaseOrderType>)unmarshallerHandler.getResult();
// process this new purchase order
process(result.getValue());
} catch( JAXBException je ) {
// error was found during the unmarshalling.
// you can either abort the processing by throwing a SAXException,
// or you can continue processing by returning from this method.
System.err.println("unable to process an order at line "+
locator.getLineNumber() );
return;
}
unmarshallerHandler = null;
}
}
}
public void process( PurchaseOrderType order ) {
System.out.println("this order will be shipped to "
+ order.getShipTo().getName() );
}
/**
* Remembers the depth of the elements as we forward
* SAX events to a JAXB unmarshaller.
*/
private int depth;
/**
* Reference to the unmarshaller which is unmarshalling
* an object.
*/
private UnmarshallerHandler unmarshallerHandler;
/**
* Keeps a reference to the locator object so that we can later
* pass it to a JAXB unmarshaller.
*/
private Locator locator;
public void setDocumentLocator(Locator locator) {
super.setDocumentLocator(locator);
this.locator = locator;
}
/**
* Used to keep track of in-scope namespace bindings.
*
* For JAXB unmarshaller to correctly unmarshal documents, it needs
* to know all the effective namespace declarations.
*/
private NamespaceSupport namespaces = new NamespaceSupport();
public void startPrefixMapping(String prefix, String uri) throws SAXException {
namespaces.pushContext();
namespaces.declarePrefix(prefix,uri);
super.startPrefixMapping(prefix, uri);
}
public void endPrefixMapping(String prefix) throws SAXException {
namespaces.popContext();
super.endPrefixMapping(prefix);
}
}