[jdom-interest] Creating new XML documents from existing XMLdocument(s)

Thu Jul 28 12:16:46 PDT 2005

The problem is that your root element now belongs to two different
Docuements. To make this work your way, you need to clone the root
element, like this...

	Element root = (Element) test.getRootElement().clone();

But, there is an easier way to replicate a Document...

	Document newDocument = (Document) test.clone();

-----Original Message-----
From: jdom-interest-bounces at jdom.org
[mailto:jdom-interest-bounces at jdom.org] On Behalf Of
robert.w2.phillips at bt.com
Sent: Thursday, July 28, 2005 2:23 PM
To: jdom-interest at jdom.org
Subject: [jdom-interest] Creating new XML documents from existing
XMLdocument(s)

Hello,

I am trying to create a new XML document from an existing XML document
using JDOM, but am unable to do so. I want to take the root element of
an existing document and use it as the root element of a new XML
document. The code I am using is as follows:

--------------------------------

import org.jdom.*;
import org.jdom.input.*;
import org.jdom.output.*;
import org.jdom.transform.*;
import java.io.StringReader;

public class JDOMTest
{
    public static void main(String[] args) throws JDOMException {
        mytest();
    }

    public static void mytest() {
        try {
            // XML String. Elements from this will form the basis of the
new XML document
            String xmlString="<?xml version=\"1.0\"
encoding=\"UTF-8\"?><note><to>Tove</to><from>Jani</from><heading>Reminde
r</heading><body>Don't forget me this weekend!</body></note>";
            SAXBuilder builder = new SAXBuilder();
            // Extract the root element from the XML string
            Document test = builder.build(new StringReader(xmlString));
            Element root = test.getRootElement(); 

            // Create a new XML document and set its root element
            Document newDocument = new Document();
            newDocument.setRootElement(root);

            System.out.println("Complete!");
        }
        catch (Exception e) {
            System.out.println("General Exception ocurred : "+e);
        }
    }
}

------------------------------

This compiles without error, but every time I run it I get the following
error:

------------------------------
> java JDOMTest
General Exception ocurred : org.jdom.IllegalAddException: The element
"note" could not be added as the root of the document: The Content
already has an existing parent document
------------------------------

Why will this not work? The problem occurs because I am trying to create
two "org.jdom.Document" objects, but this works in pre 1.0 JDOM
libraries. Is there is a restriction on the number of Document objects I
can create, or have I missed something obvious?

I have tried compiling it and running it on two different systems with
two different version of Java, but both give the same result. On Windows
XP SP2 I am using:
------------------------------
java version "1.4.2_06"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_06-b03)
Java HotSpot(TM) Client VM (build 1.4.2_06-b03, mixed mode)
------------------------------

On UNIX, I am using:
------------------------------
java version "1.4.1_03"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1_03-b02)
Java HotSpot(TM) Client VM (build 1.4.1_03-b02, mixed mode)
------------------------------

I built the JDOM.JAR library from the latest download available off the
website (1.0). As I mentioned, older (pre-1.0 release) JDOM.JAR
libraries work OK.

Any help you can offer would be most appreciated.

Best regards,

Rob.

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