Anybody familiar with JDOM?

Question

Hi,
I've been using jdom for some time now and I have been having problems with the following:
Element root = doc.getRootElement( );
List allChildren = root.getChildren( );
The List returned by the getChildren() call is a java.util.List, an implementation of the List interface all Java programmers know. What's interesting about the List is that it's live. Any changes to the List are immediately reflected in the backing document.:
allChildren.remove(3);
allChildren.add(new Element("jane"));
Somettimes the list returned by element.getChildren( ) or element.getContent( ) is empty (it should definietly not be empty). Does anybody know any possible reasons for this?

Answer 1

I am currently designing an xml-based shared text editor, where paragraphs of text are enclosed within <Paragraph> tags, then it is a matter of propagating XML elements to the users, rather than java strings.
The simple xml structure of the document is as follows. There is a <Doc> root element which contains many instances of <Paragraph> elements. These paragraph elements have textual content. The following is an example of how a new paragraph is added:
public void addElement ( int n, org.jdom.Element e, String s, boolean increment) {
e= new org.jdom.Element("Par");
e.setAttribute("id", String.valueOf(n+1));
e.setText(s);
     allPars = root.getChildren();
     allPars.add(n, e);
     if(increment == true){
     incrementAttributes(n+1);
     saveList(doc);
By sticking in print statements after allPars = root.getChildren( ), I have been getting empty lists even though the list should definitely not be empty. similar for deleteElement method and so on.
I have subsequently noticed that making the document and root element static has eliminated these problems although i had never been creating new instances of these anyway, strange.
static org.jdom.Element root = new org.jdom.Element("Doc");
static org.jdom.Document doc = new org.jdom.Document(root);