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

Thu Jul 28 12:12:08 PDT 2005

You can detach the root element from the original document and add it to the
new document.

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

-----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>Reminder</h
eading><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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