JTree to XML??

Hi,
I am (still) trying to create XML from a JTree structure. I'm completely lost. Any help would be deadly!

I didn't see anything in the API that suggests
there's a standard way of doing this.And it would not make sense since a tree model just
references objects without any indication as to how
these could be either named in xml or written in xml.Yeah but I thought there might be an "XmlTreeModel" implementation of TreeModel. But apparently there isn't.
Somebody must have made one though.
On the other hand, whenever I've needed to show an XML file in a JTree, I just wrote a TreeNode wrapper. That worked fine, but didn't support adding elements. One could create a MutableTreeNode wrapper around XML.
Actually it's probably so simple that maybe nobody has ever bothered to make something reusable. IIRC, a read-only TreeNode-around-DOM is about 40 lines of code. Mutable might be...100?

Similar Messages

Convert JTree to XML file

Hi ,
Can anyone help me in converting a JTree to XML file.
The Jtree is build from an xml file, the user can add, delete nodes in JTree and save to the xml file. Is there any way I can update the same xml file.
Suggestions are greatly appreciated.
Thanks,
SS..

Hi ,
Can anyone help me in converting a JTree to XML file.
The Jtree is build from an xml file, the user can add, delete nodes in JTree and save to the xml file. Is there any way I can update the same xml file.
Suggestions are greatly appreciated.
Thanks,
SS..

Problem with Jtree to xml tranform..how to set/get parent of a node?

Hi,
I am trying to develop xml import/export module.In import wizard, I am parsing the xml file and the display it in Jtree view using xml tree model which implements TreeModel and xml tree node.I am using jaxp api..
It is workin fine.
I got stuck with removal of selected node and save it as a new xml.
I am not able to get parent node of selected node in remove process,itz throwing null.I think i missed to define parent when i load treemodel.Plz help me out..give some ideas to do it..
thanks
-bala
Edited by: r_bala on May 9, 2008 4:44 AM

there's no way anyone can help you without seeing your code.

JTree with XML content expand/collapse problem

Hello all,
I'm having this very weird problem with a JTree I use to display the contents of an XML file. I use the DOM parser (and not JDOM since I want the application to run as an applet as well, and don't want to have any external libraries for the user to download) and have a custom TreeModel and TreeNode implementations to wrap the DOM nodes so that they are displayed by the JTree.
I have also added a popup menu in the tree, for the user to be able to expand/collapse all nodes under the selected one (i.e. a recursive method).
When expandAll is run, everything works fine and the children of the selected node are expanded (and their children and so on).
However, after the expansion when I run the collapseAll function, even though the selected node collapses, when I re-expand it (manually not by expandAll) all of it's children are still fully open! Even if I collapse sub-elements of the node manually and then collapse this node and re-expand it, it "forgets" the state of it's children and shows them fully expanded.
In other words once I use expandAll no matter what I do, the children of this node will be expanded (once I close it and re-open it).
Also after running expandAll the behaviour(!) of the expanded nodes change: i have tree.setToggleClickCount(1); but on the expanded nodes I need to double-click to collapse them.
I believe the problem is related to my implementations of TreeModel and TreeNode but after many-many hours of trying to figure out what's happening I'm desperate... Please help!
Here's my code:
public class XMLTreeNode implements TreeNode
 //This class wraps a DOM node
 org.w3c.dom.Node domNode;
 protected boolean allowChildren;
 protected Vector children;
 //compressed view (#text).
 private static boolean compress = true;
 // An array of names for DOM node-types
 // (Array indexes = nodeType() values.)
 static final String[] typeName = {
 "none",
 "Element",
 "Attr",
 "Text",
 "CDATA",
 "EntityRef",
 "Entity",
 "ProcInstr",
 "Comment",
 "Document",
 "DocType",
 "DocFragment",
 "Notation",
 static final int ELEMENT_TYPE = 1;
 static final int ATTR_TYPE = 2;
 static final int TEXT_TYPE = 3;
 static final int CDATA_TYPE = 4;
 static final int ENTITYREF_TYPE = 5;
 static final int ENTITY_TYPE = 6;
 static final int PROCINSTR_TYPE = 7;
 static final int COMMENT_TYPE = 8;
 static final int DOCUMENT_TYPE = 9;
 static final int DOCTYPE_TYPE = 10;
 static final int DOCFRAG_TYPE = 11;
 static final int NOTATION_TYPE = 12;
 // The list of elements to display in the tree
 static String[] treeElementNames = {
 "node",
// Construct an Adapter node from a DOM node
public XMLTreeNode(org.w3c.dom.Node node) {
 domNode = node;
public String toString(){
 if (domNode.hasAttributes()){
 return domNode.getAttributes().getNamedItem("label").getNodeValue();
 }else return domNode.getNodeName();
public boolean isLeaf(){
 return (this.getChildCount()==0);
boolean treeElement(String elementName) {
 for (int i=0; i<treeElementNames.length; i++) {
 if ( elementName.equals(treeElementNames)) return true;
return false;
public int getChildCount() {
 if (!compress) {
return domNode.getChildNodes().getLength();
int count = 0;
for (int i=0; i<domNode.getChildNodes().getLength(); i++) {
org.w3c.dom.Node node = domNode.getChildNodes().item(i);
if (node.getNodeType() == ELEMENT_TYPE
&& treeElement( node.getNodeName() ))
// Note:
// Have to check for proper type.
// The DOCTYPE element also has the right name
++count;
return count;
public boolean getAllowsChildren() {
 // TODO Auto-generated method stub
 return true;
public Enumeration children() {
 // TODO Auto-generated method stub
 return null;
public TreeNode getParent() {
 // TODO Auto-generated method stub
 return null;
public TreeNode getChildAt(int searchIndex) {
org.w3c.dom.Node node =
domNode.getChildNodes().item(searchIndex);
if (compress) {
// Return Nth displayable node
int elementNodeIndex = 0;
for (int i=0; i<domNode.getChildNodes().getLength(); i++) {
node = domNode.getChildNodes().item(i);
if (node.getNodeType() == ELEMENT_TYPE
&& treeElement( node.getNodeName() )
&& elementNodeIndex++ == searchIndex) {
break;
return new XMLTreeNode(node);
public int getIndex(TreeNode tnode) {
 if (tnode== null) {
 throw new IllegalArgumentException("argument is null");
 XMLTreeNode child=(XMLTreeNode)tnode;
 int count = getChildCount();
 for (int i=0; i<count; i++) {
 XMLTreeNode n = (XMLTreeNode)this.getChildAt(i);
 if (child.domNode == n.domNode) return i;
 return -1; // Should never get here.
public class XMLTreeModel2 extends DefaultTreeModel
 private Vector listenerList = new Vector();
 * This adapter converts the current Document (a DOM) into
 * a JTree model.
 private Document document;
 public XMLTreeModel2 (Document doc){
 super(new XMLTreeNode(doc));
 this.document=doc;
 public Object getRoot() {
 //System.err.println("Returning root: " +document);
 return new XMLTreeNode(document);
 public boolean isLeaf(Object aNode) {
 return ((XMLTreeNode)aNode).isLeaf();
 public int getChildCount(Object parent) {
 XMLTreeNode node = (XMLTreeNode) parent;
return node.getChildCount();
 public Object getChild(Object parent, int index) {
XMLTreeNode node = (XMLTreeNode) parent;
return node.getChildAt(index);
 public int getIndexOfChild(Object parent, Object child) {
if (parent==null || child==null )
 return -1;
 XMLTreeNode node = (XMLTreeNode) parent;
return node.getIndex((XMLTreeNode) child);
 public void valueForPathChanged(TreePath path, Object newValue) {
// Null. no changes
 public void addTreeModelListener(TreeModelListener listener) {
 if ( listener != null
&& ! listenerList.contains( listener ) ) {
listenerList.addElement( listener );
 public void removeTreeModelListener(TreeModelListener listener) {
 if ( listener != null ) {
listenerList.removeElement( listener );
 public void fireTreeNodesChanged( TreeModelEvent e ) {
Enumeration listeners = listenerList.elements();
while ( listeners.hasMoreElements() ) {
TreeModelListener listener =
(TreeModelListener) listeners.nextElement();
listener.treeNodesChanged( e );
 public void fireTreeNodesInserted( TreeModelEvent e ) {
Enumeration listeners = listenerList.elements();
while ( listeners.hasMoreElements() ) {
TreeModelListener listener =
(TreeModelListener) listeners.nextElement();
listener.treeNodesInserted( e );
 public void fireTreeNodesRemoved( TreeModelEvent e ) {
Enumeration listeners = listenerList.elements();
while ( listeners.hasMoreElements() ) {
TreeModelListener listener =
(TreeModelListener) listeners.nextElement();
listener.treeNodesRemoved( e );
 public void fireTreeStructureChanged( TreeModelEvent e ) {
Enumeration listeners = listenerList.elements();
while ( listeners.hasMoreElements() ) {
TreeModelListener listener =
(TreeModelListener) listeners.nextElement();
listener.treeStructureChanged( e );
The collapseAll, expandAll code (even though I m pretty sure that's not the problem since they work fine on a normal JTree):
 private void collapseAll(TreePath tp){
 if (tp==null) return;
 Object node=tp.getLastPathComponent();
 TreeModel model=tree.getModel();
 if (!model.isLeaf(node)){
 tree.collapsePath(tp);
 for (int i=0;i<model.getChildCount(node);i++){
 //for (int i = node.childCount()-4;i>=0;i--){
 collapseAll(tp.pathByAddingChild(model.getChild(node,i)));
 tree.collapsePath(tp);
 private void expandAll(TreePath tp){
 if (tp==null) return;
 Object node=tp.getLastPathComponent();
 TreeModel model=tree.getModel();
 if (!model.isLeaf(node)){
 tree.expandPath(tp);
 for (int i=0;i<model.getChildCount(node);i++){
 //for (int i = node.childCount()-4;i>=0;i--){
 expandAll(tp.pathByAddingChild(model.getChild(node,i)));

Hi,
Iam not facing this problem. To CollapseAll, I do a tree.getModel().reload() which causes all nodes to get collapsed and remain so even if I reopen them manually.
Hope this helps.
cheers,
vidyut

JTree with XML Content

Hi Friends,
I am trying to create a JTree whose data will come from a XML Document. Whenever the tree is refreshed (There is a JPopupMenu on the tree which allows the user to call refresh), the tree must update itself with the underlying XML document. If there is any change in the xml doc, it must be reflected in the tree. However, the tree must not collapse when the refresh is called. For example if I have a tree like this:-
+ Root
 |
 ------ Child #1
 | |
 | -------- A
 | |
 | -------- B
 |
 +------ Child #2
 |
 ------- Child #3
 |
 -------- AAA
 |
 -------- BBBThe XML Document for the above tree structure would be:-
<?xml version="1.0" encoding="UTF-8"?>
<Root>Root
 <Child> Child #1
 <SubChild>A</SubChild>
 <SubChild>B</SubChild>
 </Child>
 <Child> Child #2
 <SubChild>AA</SubChild>
 <SubChild>BB</SubChild>
 </Child>
 <Child> Child #3
 <SubChild>AAA</SubChild>
 <SubChild>BBB</SubChild>
 </Child>
</Root>Now if i add another node (CCC) in Child #3 (by adding another Subchild element in the XML document), and click refresh on the tree, the tree should look like:-
+ Root
 |
 ------ Child #1
 | |
 | -------- A
 | |
 | -------- B
 |
 +------ Child #2
 |
 ------- Child #3
 |
 -------- AAA
 |
 -------- BBB
 |
 -------- CCCHowever, if i am trying to reload the tree model, after reading the XML file, the whole tree collapses.
Can anyone please help me out with this problem?
Thanx a lot in advance,
~Debopam

* XMLNode.java
* Created on December 18, 2004, 4:25 PM
package debopam.utils.xml;
import java.util.Enumeration;
import java.util.NoSuchElementException;
import java.util.Vector;
import javax.swing.tree.MutableTreeNode;
import javax.swing.tree.TreeNode;
import org.jdom.Element;
* @author Debopam Ghoshal
public class XMLNode implements MutableTreeNode
 private Element nodeElement;
 private XMLNode parent;
 /** optional user object */
 transient protected Object userObject;
 /** true if the node is able to have children */
 protected boolean allowsChildren;
 /** array of children, may be null if this node has no children */
 protected Vector children;
 * An enumeration that is always empty. This is used when an enumeration
 * of a leaf node's children is requested.
 static public final Enumeration<TreeNode> EMPTY_ENUMERATION
 = new Enumeration<TreeNode>()
 public boolean hasMoreElements()
 { return false; }
 public TreeNode nextElement()
 throw new NoSuchElementException("No more elements");
 /** Creates a new instance of XMLNode */
 public XMLNode(Element nodeElement, boolean allowsChildren)
 this.nodeElement = nodeElement;
 this.allowsChildren = allowsChildren;
 public XMLNode(String nodeName, boolean allowsChildren)
 nodeElement = new Element(nodeName);
 this.allowsChildren = allowsChildren;
 * Creates and returns a forward-order enumeration of this node's
 * children. Modifying this node's child array invalidates any child
 * enumerations created before the modification.
 * @return an Enumeration of this node's children
 public java.util.Enumeration children()
 if(children == null)
 return EMPTY_ENUMERATION;
 else
 return children.elements();
 * Returns true if this node is allowed to have children.
 * @return true if this node allows children, else false
 public boolean getAllowsChildren()
 return allowsChildren;
 * Determines whether or not this node is allowed to have children.
 * If <code>allows</code> is false, all of this node's children are
 * removed.
 * 
 * Note: By default, a node allows children.
 * @param allows true if this node is allowed to have children
 public void setAllowsChildren(boolean allows)
 if (allows != allowsChildren)
 allowsChildren = allows;
 if (!allowsChildren)
 removeAllChildren();
 * Returns the child at the specified index in this node's child array.
 * @param index an index into this node's child array
 * @exception ArrayIndexOutOfBoundsException if <code>index</code>
 * is out of bounds
 * @return the TreeNode in this node's child array at the specified index
 public javax.swing.tree.TreeNode getChildAt(int index)
 if (children == null)
 throw new ArrayIndexOutOfBoundsException("node has no children");
 return (TreeNode)children.elementAt(index);
 * Returns the number of children of this node.
 * @return an int giving the number of children of this node
 public int getChildCount()
 if (children == null)
 return 0;
 else
 return children.size();
 * Returns the index of the specified child in this node's child array.
 * If the specified node is not a child of this node, returns
 * <code>-1</code>. This method performs a linear search and is O(n)
 * where n is the number of children.
 * @param aChild the TreeNode to search for among this node's children
 * @exception IllegalArgumentException if <code>aChild</code>
 * is null
 * @return an int giving the index of the node in this node's child
 * array, or <code>-1</code> if the specified node is a not
 * a child of this node
 public int getIndex(TreeNode aChild)
 if (aChild == null)
 throw new IllegalArgumentException("argument is null");
 if (!isNodeChild(aChild))
 return -1;
 return children.indexOf(aChild); // linear search
 * Returns this node's parent or null if this node has no parent.
 * @return this node's parent TreeNode, or null if this node has no parent
 public TreeNode getParent()
 return parent;
 * Removes <code>newChild</code> from its present parent (if it has a
 * parent), sets the child's parent to this node, and then adds the child
 * to this node's child array at index <code>childIndex</code>.
 * <code>newChild</code> must not be null and must not be an ancestor of
 * this node.
 * @param newChild the MutableTreeNode to insert under this node
 * @param childIndex the index in this node's child array
 * where this node is to be inserted
 * @exception ArrayIndexOutOfBoundsException if
 * <code>childIndex</code> is out of bounds
 * @exception IllegalArgumentException if
 * <code>newChild</code> is null or is an
 * ancestor of this node
 * @exception IllegalStateException if this node does not allow
 * children
 * @see #isNodeDescendant
 public void insert(MutableTreeNode newChild, int childIndex)
 if (!allowsChildren)
 throw new IllegalStateException("node does not allow children");
 else if (newChild == null)
 throw new IllegalArgumentException("new child is null");
 else if (isNodeAncestor(newChild))
 throw new IllegalArgumentException("new child is an ancestor");
 MutableTreeNode oldParent = (MutableTreeNode)newChild.getParent();
 if (oldParent != null)
 oldParent.remove(newChild);
 newChild.setParent(this);
 if (children == null)
 children = new Vector();
 children.insertElementAt(newChild, childIndex);
 public boolean isLeaf()
 return !nodeElement.hasChildren();
 * Removes the child at the specified index from this node's children
 * and sets that node's parent to null. The child node to remove
 * must be a <code>MutableTreeNode</code>.
 * @param childIndex the index in this node's child array
 * of the child to remove
 * @exception ArrayIndexOutOfBoundsException if
 * <code>childIndex</code> is out of bounds
 public void remove(int childIndex)
 MutableTreeNode child = (MutableTreeNode)getChildAt(childIndex);
 children.removeElementAt(childIndex);
 child.setParent(null);
 * Removes <code>aChild</code> from this node's child array, giving it a
 * null parent.
 * @param aChild a child of this node to remove
 * @exception IllegalArgumentException if <code>aChild</code>
 * is null or is not a child of this node
 public void remove(MutableTreeNode aChild)
 if (aChild == null)
 throw new IllegalArgumentException("argument is null");
 if (!isNodeChild(aChild))
 throw new IllegalArgumentException("argument is not a child");
 remove(getIndex(aChild)); // linear search
 * Removes the subtree rooted at this node from the tree, giving this
 * node a null parent. Does nothing if this node is the root of its
 * tree.
 public void removeFromParent()
 MutableTreeNode parent = (MutableTreeNode)getParent();
 if (parent != null)
 parent.remove(this);
 * Sets this node's parent to <code>newParent</code> but does not
 * change the parent's child array. This method is called from
 * <code>insert()</code> and <code>remove()</code> to
 * reassign a child's parent, it should not be messaged from anywhere
 * else.
 * @param newParent this node's new parent
 public void setParent(MutableTreeNode mutableTreeNode)
 this.parent = parent;
 public void setUserObject(Object obj)
 this.userObject = obj;
 public Element getXMLElement()
 return this.nodeElement;
 public String toString()
 return this.nodeElement.getTextTrim();
 * Returns true if <code>anotherNode</code> is an ancestor of this node
 * -- if it is this node, this node's parent, or an ancestor of this
 * node's parent. (Note that a node is considered an ancestor of itself.)
 * If <code>anotherNode</code> is null, this method returns false. This
 * operation is at worst O(h) where h is the distance from the root to
 * this node.
 * @see #isNodeDescendant
 * @see #getSharedAncestor
 * @param anotherNode node to test as an ancestor of this node
 * @return true if this node is a descendant of <code>anotherNode</code>
 public boolean isNodeAncestor(TreeNode anotherNode)
 if (anotherNode == null)
 return false;
 TreeNode ancestor = this;
 do
 if (ancestor == anotherNode)
 return true;
 } while((ancestor = ancestor.getParent()) != null);
 return false;
 * Returns true if <code>aNode</code> is a child of this node. If
 * <code>aNode</code> is null, this method returns false.
 * @return true if <code>aNode</code> is a child of this node; false if
 * <code>aNode</code> is null
 public boolean isNodeChild(TreeNode aNode)
 boolean retval;
 if (aNode == null)
 retval = false;
 else
 if (getChildCount() == 0)
 retval = false;
 else
 retval = (aNode.getParent() == this);
 return retval;
 * Removes all of this node's children, setting their parents to null.
 * If this node has no children, this method does nothing.
 public void removeAllChildren()
 for (int i = getChildCount()-1; i >= 0; i--)
 remove(i);
 * Removes <code>newChild</code> from its parent and makes it a child of
 * this node by adding it to the end of this node's child array.
 * @see #insert
 * @param newChild node to add as a child of this node
 * @exception IllegalArgumentException if <code>newChild</code>
 * is null
 * @exception IllegalStateException if this node does not allow
 * children
 public void add(MutableTreeNode newChild)
 if(newChild != null && newChild.getParent() == this)
 insert(newChild, getChildCount() - 1);
 else
 insert(newChild, getChildCount());
 * Indicates whether some other object is "equal to" this one.
 * @param obj the reference object with which to compare.
 * @return <code>true</code> if this object is the same as the obj
 * argument; <code>false</code> otherwise.
 public boolean equals(XMLNode node)
 boolean retValue;
 retValue = (this.getXMLElement().getTextTrim().equals(node.getXMLElement().getTextTrim())) &&
 (this.getXMLElement().getParent().getTextTrim().equals(node.getXMLElement().getParent().getTextTrim()));
 return retValue;
* XMLTreeModel.java
* Created on December 20, 2004, 11:29 AM
package debopam.utils.xml;
import java.io.File;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.EventListener;
import java.util.List;
import java.util.Vector;
import javax.swing.event.EventListenerList;
import javax.swing.event.TreeModelEvent;
import javax.swing.event.TreeModelListener;
import javax.swing.tree.TreeModel;
import javax.swing.tree.TreePath;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;
* @author Debopam Ghoshal
public class XMLTreeModel implements TreeModel
 private XMLNode rootNode;
 private String xmlFileName;
 private Document xmlDocument;
 /** Listeners. */
 protected EventListenerList listenerList = new EventListenerList();
 * Determines how the <code>isLeaf</code> method figures
 * out if a node is a leaf node. If true, a node is a leaf
 * node if it does not allow children. (If it allows
 * children, it is not a leaf node, even if no children
 * are present.) That lets you distinguish between folder
 * nodes and file nodes in a file system, for example.
 * 
 * If this value is false, then any node which has no
 * children is a leaf node, and any node may acquire
 * children.
 * @see TreeNode#getAllowsChildren
 * @see TreeModel#isLeaf
 * @see #setAsksAllowsChildren
 protected boolean asksAllowsChildren;
 /** Creates a new instance of XMLTreeModel */
 public XMLTreeModel(String xmlFileName, boolean asksAllowsChildren)
 this.xmlFileName = xmlFileName;
 this.asksAllowsChildren = asksAllowsChildren;
 loadXMLDocument();
 rootNode = makeRootNode();
 public XMLTreeModel(String xmlFileName)
 this(xmlFileName, false);
 private void loadXMLDocument()
 System.out.println("loading xml document...");
 try
 this.xmlDocument = null;
 this.xmlDocument = new SAXBuilder().build(new File(xmlFileName));
 catch(Exception x)
 System.out.println("Error while loading XML Document.");
 x.printStackTrace();
 private XMLNode makeRootNode()
 XMLNode root = new XMLNode(xmlDocument.getRootElement(), true);
 addChildren(root, xmlDocument.getRootElement());
 return root;
 private void addChildren(XMLNode parentXMLNode, Element element)
 List children = element.getChildren();
 for(int i = 0; i < children.size(); i++)
 Element childElement = (Element)children.get(i);
 XMLNode childNode = new XMLNode(childElement, true);
 parentXMLNode.add(childNode);
 addChildren(childNode, childElement);
 * Sets whether or not to test leafness by asking getAllowsChildren()
 * or isLeaf() to the TreeNodes. If newvalue is true, getAllowsChildren()
 * is messaged, otherwise isLeaf() is messaged.
 public void setAsksAllowsChildren(boolean newValue)
 asksAllowsChildren = newValue;
 * Tells how leaf nodes are determined.
 * @return true if only nodes which do not allow children are
 * leaf nodes, false if nodes which have no children
 * (even if allowed) are leaf nodes
 * @see #asksAllowsChildren
 public boolean asksAllowsChildren()
 return asksAllowsChildren;
 * Returns the child of parent at index index in the parent's
 * child array. parent must be a node previously obtained from
 * this data source. This should not return null if index
 * is a valid index for parent (that is index >= 0 &&
 * index < getChildCount(parent)).
 * @param parent a node in the tree, obtained from this data source
 * @return the child of parent at index index
 public Object getChild(Object parent, int index)
 return ((XMLNode)parent).getChildAt(index);
 * Returns the number of children of parent. Returns 0 if the node
 * is a leaf or if it has no children. parent must be a node
 * previously obtained from this data source.
 * @param parent a node in the tree, obtained from this data source
 * @return the number of children of the node parent
 public int getChildCount(Object parent)
 return ((XMLNode)parent).getChildCount();
 * Returns the index of child in parent.
 * If either the parent or child is <code>null</code>, returns -1.
 * @param parent a note in the tree, obtained from this data source
 * @param child the node we are interested in
 * @return the index of the child in the parent, or -1
 * if either the parent or the child is <code>null</code>
 public int getIndexOfChild(Object parent, Object child)
 if(parent == null || child == null)
 return -1;
 return ((XMLNode)parent).getIndex((XMLNode)child);
 * Sets the root to <code>root</code>. A null <code>root</code> implies
 * the tree is to display nothing, and is legal.
 public void setRoot(XMLNode rootNode)
 Object oldRoot = this.rootNode;
 this.rootNode = rootNode;
 if (rootNode == null && oldRoot != null)
 fireTreeStructureChanged(this, null);
 else
 nodeStructureChanged(rootNode);
 * Returns the root of the tree. Returns null only if the tree has
 * no nodes.
 * @return the root of the tree
 public Object getRoot()
 return rootNode;
 * Returns whether the specified node is a leaf node.
 * The way the test is performed depends on the
 * <code>askAllowsChildren</code> setting.
 * @param node the node to check
 * @return true if the node is a leaf node
 * @see #asksAllowsChildren
 * @see TreeModel#isLeaf
 public boolean isLeaf(Object node)
 if(asksAllowsChildren)
 return !((XMLNode)node).getAllowsChildren();
 return ((XMLNode)node).isLeaf();
 * This sets the user object of the TreeNode identified by path
 * and posts a node changed. If you use custom user objects in
 * the TreeModel you're going to need to subclass this and
 * set the user object of the changed node to something meaningful.
 public void valueForPathChanged(TreePath path, Object newValue)
 XMLNode aNode = (XMLNode)path.getLastPathComponent();
 aNode.setUserObject(newValue);
 nodeChanged(aNode);
 * Invoked this to insert newChild at location index in parents children.
 * This will then message nodesWereInserted to create the appropriate
 * event. This is the preferred way to add children as it will create
 * the appropriate event.
 public void insertNodeInto(XMLNode newChild, XMLNode parent, int index)
 parent.insert(newChild, index);
 int[] newIndexs = new int[1];
 newIndexs[0] = index;
 nodesWereInserted(parent, newIndexs);
 * Message this to remove node from its parent. This will message
 * nodesWereRemoved to create the appropriate event. This is the
 * preferred way to remove a node as it handles the event creation
 * for you.
 public void removeNodeFromParent(XMLNode node)
 XMLNode parent = (XMLNode)node.getParent();
 if(parent == null)
 throw new IllegalArgumentException("node does not have a parent.");
 int[] childIndex = new int[1];
 Object[] removedArray = new Object[1];
 childIndex[0] = parent.getIndex(node);
 parent.remove(childIndex[0]);
 removedArray[0] = node;
 nodesWereRemoved(parent, childIndex, removedArray);
 * Invoke this method after you've changed how node is to be
 * represented in the tree.
 public void nodeChanged(XMLNode node)
 if(listenerList != null && node != null)
 XMLNode parent = (XMLNode)node.getParent();
 if(parent != null)
 int anIndex = parent.getIndex(node);
 if(anIndex != -1)
 int[] cIndexs = new int[1];
 cIndexs[0] = anIndex;
 nodesChanged(parent, cIndexs);
 else if (node == getRoot())
 nodesChanged(node, null);
 * Invoke this method if you've modified the TreeNodes upon which this
 * model depends. The model will notify all of its listeners that the
 * model has changed.
 public void reload()
 loadXMLDocument();
 XMLNode tempRootNode = makeRootNode();
 if(!tempRootNode.equals(rootNode))
 // Means that the root node itself has changed.
 System.out.println("Root node changed");
 reload(rootNode);
 //else
 checkForNodesChanged(tempRootNode, rootNode);
 * Invoke this method if you've modified the TreeNodes upon which this
 * model depends. The model will notify all of its listeners that the
 * model has changed below the node <code>node</code> (PENDING).
 public void reload(XMLNode node)
 if(node != null)
 fireTreeStructureChanged(this, getPathToRoot(node), null, null);
 * Invoke this method after you've inserted some TreeNodes into
 * node. childIndices should be the index of the new elements and
 * must be sorted in ascending order.
 public void nodesWereInserted(XMLNode node, int[] childIndices)
 if(listenerList != null && node != null && childIndices != null
 && childIndices.length > 0)
 int cCount = childIndices.length;
 Object[] newChildren = new Object[cCount];
 for(int counter = 0; counter < cCount; counter++)
 newChildren[counter] = node.getChildAt(childIndices[counter]);
 fireTreeNodesInserted(this, getPathToRoot(node), childIndices,
 newChildren);
 * Invoke this method after you've removed some TreeNodes from
 * node. childIndices should be the index of the removed elements and
 * must be sorted in ascending order. And removedChildren should be
 * the array of the children objects that were removed.
 public void nodesWereRemoved(XMLNode node, int[] childIndices,
 Object[] removedChildren)
 if(node != null && childIndices != null)
 fireTreeNodesRemoved(this, getPathToRoot(node), childIndices,
 removedChildren);
 * Invoke this method after you've changed how the children identified by
 * childIndicies are to be represented in the tree.
 public void nodesChanged(XMLNode node, int[] childIndices)
 if(node != null)
 if (childIndices != null)
 int cCount = childIndices.length;
 if(cCount > 0)
 Object[] cChildren = new Object[cCount];
 for(int counter = 0; counter < cCount; counter++)
 cChildren[counter] = node.getChildAt
 (childIndices[counter]);
 fireTreeNodesChanged(this, getPathToRoot(node),
 childIndices, cChildren);
 else if (node == getRoot())
 fireTreeNodesChanged(this, getPathToRoot(node), null, null);
 * Invoke this method if you've totally changed the children of
 * node and its childrens children... This will post a
 * treeStructureChanged event.
 public void nodeStructureChanged(XMLNode node)
 if(node != null)
 fireTreeStructureChanged(this, getPathToRoot(node), null, null);
 * Builds the parents of node up to and including the root node,
 * where the original node is the last element in the returned array.
 * The length of the returned array gives the node's depth in the
 * tree.
 * @param aNode the TreeNode to get the path for
 public XMLNode[] getPathToRoot(XMLNode aNode)
 return getPathToRoot(aNode, 0);
 * Builds the parents of node up to and including the root node,
 * where the original node is the last element in the returned array.
 * The length of the returned array gives the node's depth in the
 * tree.
 * @param aNode the TreeNode to get the path for
 * @param depth an int giving the number of steps already taken towards
 * the root (on recursive calls), used to size the returned array
 * @return an array of TreeNodes giving the path from the root to the
 * specified node
 protected XMLNode[] getPathToRoot(XMLNode aNode, int depth)
 XMLNode[] retNodes;
 // This method recurses, traversing towards the root in order
 // size the array. On the way back, it fills in the nodes,
 // starting from the root and working back to the original node.
 /* Check for null, in case someone passed in a null node, or
 they passed in an element that isn't rooted at root. */
 if(aNode == null)
 if(depth == 0)
 return null;
 else
 retNodes = new XMLNode[depth];
 else
 depth++;
 if(aNode == rootNode)
 retNodes = new XMLNode[depth];
 else
 retNodes = getPathToRoot((XMLNode)aNode.getParent(), depth);
 retNodes[retNodes.length - depth] = aNode;
 return retNodes;
 // Events
 * Adds a listener for the TreeModelEvent posted after the tree changes.
 * @see #removeTreeModelListener
 * @param l the listener to add
 public void addTreeModelListener(TreeModelListener l)
 listenerList.add(TreeModelListener.class, l);
 * Removes a listener previously added with addTreeModelListener().
 * @see #addTreeModelListener
 * @param l the listener to remove
 public void removeTreeModelListener(TreeModelListener l)
 listenerList.remove(TreeModelListener.class, l);
 * Returns an array of all the tree model listeners
 * registered on this model.
 * @return all of this model's <code>TreeModelListener</code>s
 * or an empty
 * array if no tree model listeners are currently registered
 * @see #addTreeModelListener
 * @see #removeTreeModelListener
 * @since 1.4
 public TreeModelListener[] getTreeModelListeners()
 return (TreeModelListener[])listenerList.getListeners(
 TreeModelListener.class);
 * Notifies all listeners that have registered interest for
 * notification on this event type. The event instance
 * is lazily created using the parameters passed into
 * the fire method.
 * @param source the node being changed
 * @param path the path to the root node
 * @param childIndices the indices of the changed elements
 * @param children the changed elements
 * @see EventListenerList
 protected void fireTreeNodesChanged(Object source, Object[] path,
 int[] childIndices,
 Object[] children)
 // Guaranteed to return a non-null array
 Object[] listeners = listenerList.getListenerList();
 TreeModelEvent e = null;
 // Process the listeners last to first, notifying
 // those that are interested in this event
 for (int i = listeners.length-2; i>=0; i-=2)
 if (listeners==TreeModelListener.class)
// Lazily create the event:
if (e == null)
e = new TreeModelEvent(source, path,
childIndices, children);
((TreeModelListener)listeners[i+1]).treeNodesChanged(e);
* Notifies all listeners that have registered interest for
* notification on this event type. The event instance

Converting jtree to xml

hi, i am currently working on a project where i construct a jtree using a java gui....once the user clicks on save button, the jtree has to be read and converted into an xml document....
for eg, the jtree looks like this
- process
----reply
----receive
etc..
the xml document should be as follows:
<process>
<reply> </reply>
<receive></receive>
</process>
i need your help in this regard....kindly help
Regards
Lalitha

Chapter 23 of the book, constructs a tree XMl editor, and it saves among other things...
http://www.manning.com/sbe/

Create JTree from XML

hi. I have created a simple XML file which contains a hierarchical structure of strings.
Also, I have created a SAXParser to read from the xml.
But I don't know how to put this structure in a JTree.
I don't want the tree to appear on my screen. I just want to access certain nodes at different times.
Any help?

Hello,
If it's not to display it, you certainly don't need a JTree to store your data.
Maybe you need to use a DOMParser instead but that shouldn't prevent you from building a more appropriate data model.

Transforming JTree to XML

Hi,
I have created a JTree from a DOM Document.
I need to be able to transform the data from the JTree back to a DOM.
Or update only certain nodes, on the DOM corresponding to the DOM.
Has anyone ever done anything like this,
Regards,
IJ...

i cant answer your question but im wondering if u might give me a few tips on where to start with xml. Basically, i want to pull elements of an xml document from the web daily,and display them on my website. my problem is that i don't know where to start and what i need, any help would be appreciated, im desperate!

Convert XML to JTree

Hey,
Does anyone have any code on how to convert an XML file into a JTree. I also need to be able to convert a JTree into XML.
Any help would be great!

http://java.sun.com/webservices/jaxp/dist/1.1/docs/tutorial/dom/3_tree.html

Generate XML file from a JTree

I have created a JTree wich displays the contnet of the filesystem. Each node has a checkbox to select a file or directory for a later use. (For example : copy all selected files into a backup drive).
Now i want to save the selected node into a xml file and looking for the best way . I now , how JDOM works and so on, but i am looking for a good xml structure for this. Also what is the best approach to do this ? Does anybody have experiences on this area ?

many thanks for your answer !
i have more than one selected node. So it seems, that one of my job is, how to tell the parent nodes, that i have select a node ? Also when i write the Jtree to xml , i would use an attribute for the directory node to indicate , that one or more child files/directories are selected. So i could skip directories without selected nodes. Do you agree ?
Why do you prefer working with with attributes ? Because of personal experiences or performance issues ?
Importend !!! The another idea is, to store a default profile (all dir's and files) that should be included in a backup process in xml. So i would use your approach with changes likes this :
<FILESYSTEM>
<DIR name="ROOT">
<DIR name="%program files\eclipse\workspace" >
</DIR>
<DIR name="%program files%\microsoft" >
<FILE name="*.doc" />
</DIR>
</FILESYSTEM>
In this example all content of the eclipse workspace dir will be stored and from the microsoft dir, only *.doc fileswill be stored. When i display these all in a jtree, these dir's and files will be signed as selected.
Anyone has a better idea ?

Remove white space nodes from jtree

I am trying to create jtree using XML DOM.
But I m not able to remove/ignore the white space elements from DOM.
I am getting output something like this
for example
Server
Text
node1
Text
I want something like this.
Server
node1
I tried all option for removeing the white space
Here I am posting the source
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.FactoryConfigurationError;
import javax.xml.parsers.ParserConfigurationException;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import java.io.File;
import java.io.IOException;
import org.w3c.dom.Document;
import org.w3c.dom.DOMException;
// Basic GUI components
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
// GUI components for right-hand side
import javax.swing.JSplitPane;
import javax.swing.JEditorPane;
// GUI support classes
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.WindowEvent;
import java.awt.event.WindowAdapter;
// For creating borders
import javax.swing.border.EmptyBorder;
import javax.swing.border.BevelBorder;
import javax.swing.border.CompoundBorder;
// For creating a TreeModel
import javax.swing.tree.*;
import javax.swing.event.*;
import java.util.*;
public class DomEcho02 extends JPanel
// Global value so it can be ref'd by the tree-adapter
static Document document;
static final int windowHeight = 460;
static final int leftWidth = 300;
static final int rightWidth = 340;
static final int windowWidth = leftWidth + rightWidth;
public DomEcho02()
// Make a nice border
EmptyBorder eb = new EmptyBorder(5,5,5,5);
BevelBorder bb = new BevelBorder(BevelBorder.LOWERED);
CompoundBorder cb = new CompoundBorder(eb,bb);
this.setBorder(new CompoundBorder(cb,eb));
// Set up the tree
JTree tree = new JTree(new DomToTreeModelAdapter());
// Iterate over the tree and make nodes visible
// (Otherwise, the tree shows up fully collapsed)
//TreePath nodePath = ???;
// tree.expandPath(nodePath);
// Build left-side view
JScrollPane treeView = new JScrollPane(tree);
treeView.setPreferredSize(
new Dimension( leftWidth, windowHeight ));
// Build right-side view
JEditorPane htmlPane = new JEditorPane("text/html","");
htmlPane.setEditable(false);
JScrollPane htmlView = new JScrollPane(htmlPane);
htmlView.setPreferredSize(
new Dimension( rightWidth, windowHeight ));
// Build split-pane view
JSplitPane splitPane =
new JSplitPane( JSplitPane.HORIZONTAL_SPLIT,
treeView,
htmlView );
splitPane.setContinuousLayout( true );
splitPane.setDividerLocation( leftWidth );
splitPane.setPreferredSize(
new Dimension( windowWidth + 10, windowHeight+10 ));
// Add GUI components
this.setLayout(new BorderLayout());
this.add("Center", splitPane );
} // constructor
public static void main(String argv[])
if (argv.length != 1) {
System.err.println("Usage: java DomEcho filename");
System.exit(1);
DocumentBuilderFactory factory =
DocumentBuilderFactory.newInstance();
//factory.setValidating(true);
//factory.setNamespaceAware(true);
try {
DocumentBuilder builder = factory.newDocumentBuilder();
document = builder.parse( new File(argv[0]) );
makeFrame();
} catch (SAXException sxe) {
// Error generated during parsing)
Exception x = sxe;
if (sxe.getException() != null)
x = sxe.getException();
x.printStackTrace();
} catch (ParserConfigurationException pce) {
// Parser with specified options can't be built
pce.printStackTrace();
} catch (IOException ioe) {
// I/O error
ioe.printStackTrace();
} // main
public static void makeFrame() {
// Set up a GUI framework
JFrame frame = new JFrame("DOM Echo");
frame.addWindowListener(
new WindowAdapter() {
public void windowClosing(WindowEvent e) {System.exit(0);}
// Set up the tree, the views, and display it all
final DomEcho02 echoPanel =
new DomEcho02();
frame.getContentPane().add("Center", echoPanel );
frame.pack();
Dimension screenSize =
Toolkit.getDefaultToolkit().getScreenSize();
int w = windowWidth + 10;
int h = windowHeight + 10;
frame.setLocation(screenSize.width/3 - w/2,
screenSize.height/2 - h/2);
frame.setSize(w, h);
frame.setVisible(true);
} // makeFrame
// An array of names for DOM node-types
// (Array indexes = nodeType() values.)
static final String[] typeName = {
"none",
"Element",
"Attr",
"Text",
"CDATA",
"EntityRef",
"Entity",
"ProcInstr",
"Comment",
"Document",
"DocType",
"DocFragment",
"Notation",
// This class wraps a DOM node and returns the text we want to
// display in the tree. It also returns children, index values,
// and child counts.
public class AdapterNode
org.w3c.dom.Node domNode;
// Construct an Adapter node from a DOM node
public AdapterNode(org.w3c.dom.Node node) {
domNode = node;
// Return a string that identifies this node in the tree
// *** Refer to table at top of org.w3c.dom.Node ***
public String toString() {
String s = typeName[domNode.getNodeType()];
String nodeName = domNode.getNodeName();
if (! nodeName.startsWith("#")) {
s += ": " + nodeName;
if (domNode.getNodeValue() != null) {
if (s.startsWith("ProcInstr"))
s += ", ";
else
s += ": ";
// Trim the value to get rid of NL's at the front
String t = domNode.getNodeValue().trim();
int x = t.indexOf("\n");
if (x >= 0) t = t.substring(0, x);
s += t;
return s;
* Return children, index, and count values
public int index(AdapterNode child) {
//System.err.println("Looking for index of " + child);
int count = childCount();
for (int i=0; i<count; i++) {
AdapterNode n = this.child(i);
if (child.domNode == n.domNode) return i;
return -1; // Should never get here.
public AdapterNode child(int searchIndex) {
//Note: JTree index is zero-based.
org.w3c.dom.Node node =
domNode.getChildNodes().item(searchIndex);
return new AdapterNode(node);
public int childCount() {
return domNode.getChildNodes().getLength();
// This adapter converts the current Document (a DOM) into
// a JTree model.
public class DomToTreeModelAdapter
implements javax.swing.tree.TreeModel
// Basic TreeModel operations
public Object getRoot() {
//System.err.println("Returning root: " +document);
return new AdapterNode(document);
public boolean isLeaf(Object aNode) {
// Determines whether the icon shows up to the left.
// Return true for any node with no children
AdapterNode node = (AdapterNode) aNode;
if (node.childCount() > 0) return false;
return true;
public int getChildCount(Object parent) {
AdapterNode node = (AdapterNode) parent;
return node.childCount();
public Object getChild(Object parent, int index) {
AdapterNode node = (AdapterNode) parent;
return node.child(index);
public int getIndexOfChild(Object parent, Object child) {
AdapterNode node = (AdapterNode) parent;
return node.index((AdapterNode) child);
public void valueForPathChanged(TreePath path, Object newValue) {
// Null. We won't be making changes in the GUI
// If we did, we would ensure the new value was really new,
// adjust the model, and then fire a TreeNodesChanged event.
* Use these methods to add and remove event listeners.
* (Needed to satisfy TreeModel interface, but not used.)
private Vector listenerList = new Vector();
public void addTreeModelListener(TreeModelListener listener) {
if ( listener != null
&& ! listenerList.contains( listener ) ) {
listenerList.addElement( listener );
public void removeTreeModelListener(TreeModelListener listener) {
if ( listener != null ) {
listenerList.removeElement( listener );
// Note: Since XML works with 1.1, this example uses Vector.
// If coding for 1.2 or later, though, I'd use this instead:
// private List listenerList = new LinkedList();
// The operations on the List are then add(), remove() and
// iteration, via:
// Iterator it = listenerList.iterator();
// while ( it.hasNext() ) {
// TreeModelListener listener = (TreeModelListener) it.next();
* Invoke these methods to inform listeners of changes.
* (Not needed for this example.)
* Methods taken from TreeModelSupport class described at
* http://java.sun.com/products/jfc/tsc/articles/jtree/index.html
* That architecture (produced by Tom Santos and Steve Wilson)
* is more elegant. I just hacked 'em in here so they are
* immediately at hand.
public void fireTreeNodesChanged( TreeModelEvent e ) {
Enumeration listeners = listenerList.elements();
while ( listeners.hasMoreElements() ) {
TreeModelListener listener =
(TreeModelListener) listeners.nextElement();
listener.treeNodesChanged( e );
public void fireTreeNodesInserted( TreeModelEvent e ) {
Enumeration listeners = listenerList.elements();
while ( listeners.hasMoreElements() ) {
TreeModelListener listener =
(TreeModelListener) listeners.nextElement();
listener.treeNodesInserted( e );
public void fireTreeNodesRemoved( TreeModelEvent e ) {
Enumeration listeners = listenerList.elements();
while ( listeners.hasMoreElements() ) {
TreeModelListener listener =
(TreeModelListener) listeners.nextElement();
listener.treeNodesRemoved( e );
public void fireTreeStructureChanged( TreeModelEvent e ) {
Enumeration listeners = listenerList.elements();
while ( listeners.hasMoreElements() ) {
TreeModelListener listener =
(TreeModelListener) listeners.nextElement();
listener.treeStructureChanged( e );
}

DocumentBuilderFactory can be configured to ignore white space.
http://java.sun.com/j2se/1.5.0/docs/api/javax/xml/parsers/DocumentBuilderFactory.html#setIgnoringElementContentWhitespace(boolean)

Tree query using XML SQL

Hi,
Any ideas or code samples of how we could use the XML SQL Utility
to do a tree structure, like the following:
<GROUP id="grp1">
<ITEM> item 1 </ITEM>
<ITEM> item 2 </ITEM>
<GROUP id="grp2">
<ITEM> item 3 </ITEM>
<ITEM> item 4 </ITEM>
</GROUP>
<ITEM> item 5 </ITEM>
</GROUP>
Thanks,
Cyril.
null

Hi Mark,
To a certain extent one can modify the xml generated by
manipulating the query and by using some of the tag name
customizations which the XSU allows. Unfortunately, what you
want to create will take more than that; you will have to use
XSLT - xml transformation language, part of XSL. You will find
and XSL processor packaged with the oracle xml parser v2 (see
oraxsl). You can find more info on XSLT at www.w3c.org
Mark Fortner (guest) wrote:
: I have an example similar to his:
: Given a resultset in the form:
: Company Department User
: Oracle XML Dev John Smith
: Oracle XML Dev Jane Smith
: Oracle Mgmt Larry Ellison
: Sun Project X Jane Doe
: Sun Mgmt Scott McNealy
: which usually results in XML like this
: <rowset>
: <row id=1>
: <Company>Oracle</Company>
: <Department>XML Dev</Department>
: <User>John Smith</User>
: </row>
: </rowset>
: how do I get it to look like this?
: <JTree>
: <Oracle>
: <XML Dev>
: <Jane Smith/>
: <John Smith/>
: </XML Dev>
: <Mgmt>
: <Larry Ellison/>
: </Mgmt>
: </Oracle>
: <Sun>
: <Project X>
: <Jane Doe/>
: </Project X>
: <Mgmt>
: <Scott McNealy/>
: </Mgmt>
: </Sun>
: </JTree>
: Oracle XML Team wrote:
: : Hi Cyril,
: : Your question is a bit vague. Do you have a table which
you
: : are trying to query and get the result in the following
: format?
: : If these is the case please give me the description of the
: table
: : or the view.
: : The other thing to keep in mind is that even if the XSU
: can't
: : give you the XML data in the exactly the format you want, you
: can
: : always use XSLT to transform the XML doc generated by the XSU
: to
: : the desired XML doc.
: : Cyril Dunnion (guest) wrote:
: : : Hi,
: : : Any ideas or code samples of how we could use the XML SQL
: : Utility
: : : to do a tree structure, like the following:
: : : <GROUP id="grp1">
: : : <ITEM> item 1 </ITEM>
: : : <ITEM> item 2 </ITEM>
: : : <GROUP id="grp2">
: : : <ITEM> item 3 </ITEM>
: : : <ITEM> item 4 </ITEM>
: : : </GROUP>
: : : <ITEM> item 5 </ITEM>
: : : </GROUP>
: : : Thanks,
: : : Cyril.
: : Oracle Technology Network
: : http://technet.oracle.com
Oracle Technology Network
http://technet.oracle.com
null

Help on Generic Plugable module

Hi to all
I am going to create a generic plugable module for swing application. My project is a xml editor that create jtree from xml files
and now i want some nodes on jtree that are part of generic plugable module, if i remove this module then my existing work should work properley , Please help me if someone give me example or an idea then it will be great help for me.
Thanx

Hi ,
can u share ur experience for correcting this error .
and how can i define deleta for this data sources ...
the delta is based on the Udate field ( calander day ) ...
i assign points....
Regards,
PSR

Best way to store objects' properties and later remake those objects?

I want to create a bunch of objects, set their properties and then save that so on restart, the objects can be reconstituted. Is serialization the best way/ Some other way? I want to store them in XML so I can also create a GUI to show the objects stored.

JoachimSauer wrote:
6tr6tr wrote:
I want to create a bunch of objects, set their properties and then save that so on restart, the objects can be reconstituted. Is serialization the best way/ Some other way?Serialization is definitely one way to do that.
I want to store them in XMLUse JAXB or XMLEncoder/XMLDecoder.
so I can also create a GUI to show the objects stored.What does a GUI have to do with writing XML? I don't see how that's in any way related.Thanks. What I meant was that I want to have a JTree populated easily with that info and I know there's good support for populating a JTree with XML.

Weird JFrame Behavior

I am loading a JTree with XML data into a JFrame. When I choose File -> Close on the frame, I want to remove the JTree. I do this by using getContentPane().remove(this). That works for me.
When I choose File-> Open to load a new JTree, it loads the new JTree and then slaps the previously loaded tree on top of it. That's a problem
I've played around with the repaints and validates. None of it seems to work.
Any thoughts welcomed.

hmmmm....
this.add("Center", jScrollArea );
would just replace whatever is at "Center" with the new scrollpane.
frame.getContentPane().add(this);
Unless you've changed the content pane's layout, the default is BorderLayout, so this should be added to the center, thus replace what was there, which of course if it's the same component, it's basically a no-op...
Of course, if you are just updating the tree in the same class, you could simply write it like this (no reason not to just reuse the same tree and scrollpane, just change the tree's contents):
 TreeDisplayPanel td = new TreeDisplayPanel();
 frame.getContentPane().add(td);
public class TreeDisplayPanel extends JPanel {
 private JTree jTree;
 public TreeDisplayPanel() {
 // Make a nice border
 this.setBorder(new CompoundBorder(compoundBorder,emptyBorder));
 DefaultTreeModel defaultTreeModel = new DefaultTreeModel(new DefaultMutableTreeNode("<open a file>"));
 jTree = new JTree(defaultTreeModel);
 // JTree look and feel
 jTree.getSelectionModel().setSelectionMode
 (TreeSelectionModel.SINGLE_TREE_SELECTION);
 jTree.putClientProperty("JTree.lineStyle", "Angled");
 jTree.setShowsRootHandles(true);
 jTree.setEditable(false);
 // Force the scrollable area of the screen to be independent of
 // the size of the XML being displayed
 JScrollPane jScrollArea = new JScrollPane(jTree)
 // Keep the scroll pane a reasonable size
 public Dimension getPreferredSize()
 return new Dimension(FRAME_WIDTH - 20,
 FRAME_HEIGHT - 40);
 // Add the scroll pane which contains the tree
 this.setLayout(new BorderLayout());
 this.add("Center", jScrollArea );
 public void displayTree(Node root)
 DefaultMutableTreeNode treeRoot = treeNode.createTreeNode(root);
 jTree.setModel(new DefaultTreeModel(treeRoot));
 revalidate();
 repaint();
 }

JTree to XML??

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