Jdom parsing problem

[sudhakarpothu]

Hello Friends,

I am trying to parse two xml documents (using JDOM) and create a third one which is combination of these two. following is the code I'm using.

import java.io.*;
import java.util.Iterator;
import java.io.IOException;
import java.util.List ;

import org.jdom.*;
import org.jdom.input.*;
import org.jdom.output.Format;
import org.jdom.input.SAXBuilder;
import org.jdom.output.XMLOutputter;
import org.jdom.JDOMException;
import org.xml.sax.InputSource ;
import org.jdom.input.SAXBuilder;
import org.jdom.xpath.XPath;

public class Merger {
public static void main(String[] args){

String filename=new String("demosystem.xml");

try {

SAXBuilder builder = new SAXBuilder();

Document doc = builder.build (new File "demoSystem1.xml"));
Document doc1 = builder.build(new File("demoSystem2.xml"));

Document doctoWrite=new Document();
doctoWrite=doc;

//doctoWrite.getRootElement()addContent((Element)( doc1.getRootElement().clone()));

doctoWrite.getRootElement().getChild("application").addContent((Element)( doc1.getRootElement().getChild("application").getChild("source").clone()));

try {
XMLOutputter serializer = new XMLOutputter();
FileOutputStream out = new FileOutputStream(filename);
serializer.output(doctoWrite,out);
}
catch (IOException e) {
System.err.println(e);
}

}catch (Exception e) {
e.printStackTrace ();
}
}
}


//doctoWrite.getRootElement()addContent((Element)( doc1.getRootElement().clone()));

This commented line is working properly when i use it and I am able to merge both the XML.



But when I am trying to include it in the child "application" it is giving me null pointer exception

doctoWrite.getRootElement().getChild("application").addContent((Element)( doc1.getRootElement().getChild("application").getChild("source").clone()));



My XML is

Sys version="2" xsi:schemaLocation="----------------.xsd">
<!--Definition of the application structure-->
?|
<application>
?|
<source name="S0" orientation="false" xPosition="120" yPosition="180" width="140" height="100">

.................................
....................


Please help me what I am doing wrong in this case. Should I use some schema and parse it?

Thanks in advance

 

[Diancecht]

Well, there are like eight sources of the exception in the same line: I'd try either to debug it to know where the null is coming from or if you don't feel confortable debugging, just split the line to see in which one the exception is being thrown.

With that info, you will be in a better position to analyze the error.

Cheers,
Dian

 

[sudhakarpothu]

THis line of code is working fine

doctoWrite.getRootElement().addContent((Element)( doc1.getRootElement().clone()));


but when I include .getChild("application") (as below) I have NULL pointer exception

doctoWrite.getRootElement().getChild("application").addContent((Element)( doc1.getRootElement().clone()));

 

[timw]

... but you should be aware at this point that in order to copy the contents of one XML document to another, you need to call the Document.importNode method on the content first.

http://java.sun.com/j2se/1.4.2/docs...nt.html#importNode(org.w3c.dom.Node, boolean)

Tim

 

[sudhakarpothu]

I am able to do it if i take out the version="2" xsi:schemaLocation="----------------.xsd"> from root element.

So the clone() doesn't work with schema?

Please write as I am very new to Java programming

 

[Diancecht]

Then the problem may be that the document you're writing doesn't have a node called "application" yet.

Cheers,
Dian

 

[Diancecht]

Btw, a couple of links with info about this:

http://www.exampledepot.com/egs/org.w3c.dom/MergeText.html

http://www.theserverside.com/news/thread.tss?thread_id=28149

Cheers,
Dian

 

[sudhakarpothu]

What I see in the XML document is a root <Sys....... then the next element is <application>

Sys version="2" xsi:schemaLocation="----------------.xsd">
<!--Definition of the application structure-->
?|
<application>