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

Thu Jul 28 12:14:06 PDT 2005

I think this is in the FAQ.  You have to remove an element from its old 
parent before letting it be adopted by a new.  The elt.detach() method 
is convenient for this.

-jh-

robert.w2.phillips at bt.com wrote:
> 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</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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