Adding XML Document as a Child

Adding an XMLDocument as a Child to Another Element

Question

I am trying to add an XMLDocument as a child to an existing element. Here's an example:

import org.w3c.dom.*;
import java.util.*;
import java.io.*;
import java.net.*;
import oracle.xml.parser.v2.*;
public class ggg {public static void main (String [] args) throws Exception
 {
new ggg().doWork();;
public void doWork() throws Exception {XMLDocument doc1 = new XMLDocument();
Element root1=doc1.createElement("root1");
XMLDocument doc2= new XMLDocument();	Element root2=doc2.createElement("root2");
	root1.appendChild(root2);
doc1.print(System.out);};};

This reports:

D:\Temp\Oracle\sample>c:\jdk1.2.2\bin\javac -classpath 
D:\Temp\Oracle\lib\xmlparserv2.jar;. 
ggg.javaD:\Temp\Oracle\sample>c:\jdk1.2.2\bin\java -classpath 
D:\Temp\Oracle\lib\xmlparserv2.jar;. gggException in thread "main" 
java.lang.NullPointerException        at 
oracle.xml.parser.v2.XMLDOMException.(XMLDOMException.java:67)        at 
oracle.xml.parser.v2.XMLNode.checkDocument(XMLNode.java:919)        at 
oracle.xml.parser.v2.XMLNode.appendChild(XMLNode.java, Compiled Code)        at 
oracle.xml.parser.v2.XMLNode.appendChild(XMLNode.java:494)        at 
ggg.doWork(ggg.java:20)        at ggg.main(ggg.java:12)

Answer a

The following works for me: :

DocumentFragment rootNode = new XMLDocumentFragment(); DOMParser d  = new 
DOMParser(); d.parse("http://.../stuff.xml"); 
Document doc = d.getDocument(); 
Element e = doc.getDocumentElement(); 
// Important to remove it from the first doc 
// before adding it to the other doc. doc.removeChild(e); 
rootNode.appendChild(e); 

You need to use the DocumentFragment class to do this as a document cannot have more than one root.

Answer b

Actually, isn't this specifically a problem with appending a node created in another document, since all nodes contain a reference to the document they are created in? While Document Fragmentsolves this, it isn't a more than one root problem, is it? Is there a quick or easy way to convert a com.w3c.dom.Document to org.w3c.dom.DocumentFragment?

Adding an XMLDocumentFragment as a Child to XMLDocument

Question

I have this piece of code:

XSLStylesheet XSLProcessorStylesheet = new XSLStylesheet(XSLProcessorDoc, 
XSLProcessorURL);
XSLStylesheet XSLRendererStylesheet = new XSLStylesheet(XSLRendererDoc, 
XSLRendererURL);
XSLProcessor processor = new XSLProcessor();
// configure the processorprocessor.showWarnings(true);
processor.setErrorStream(System.err);
XMLDocumentFragment processedXML = processor.processXSL(XSLProcessorStylesheet, 
XMLInputDoc);
XMLDocumentFragment renderedXML = processor.processXSL(XSLRendererStylesheet, 
processedXML);
Document resultXML = new XMLDocument();
resultXML.appendChild(renderedXML);

The last line causes Exception in thread "main" oracle.xml.parser.v2.

XMLDOMException: Node of this type cannot be added.

Do I have to create a root element _every time_, even if I know that the resulting DocumentFragment is a well formed XML Document (and of course has only one root element!)?

Answer

It happens, as you have guessed, because a Fragment can have more than one "root" element (for lack of a better term). In order towork around this, use the Node functions to extract the one rootelement from your fragment and cast it into an