JTree and JPanel

I have an application in which I have two separate dialog boxes that have multiple tabs (Panels) on them to set program options. I would like to update this UI to have a single dialog box that has a JTree on the left hand side of the dialog and have it update the Panel on the right hand side of the dialog. I am not 100% certain of how to achieve this. There are 2 issues
1) How to I update the panel corresponding to the node clicked in the JTree. I assume I need to add a listener so when a node is clicked I need to update the JPanel.
2) I assume that I do not want to create/destroy each JPanel associated with each JTree entry whenever a node is clicked. This would imply creating all JPanels when the dialog box is created. Do I create another JPanel/ScrollPane for the right hand side of the dialog box as a container and add these individual JPanels to it?
The Dialog box looks similar to
LHS RHS
JTree JPanel (changes based on JTree node selected)
The JTree looks similar to the following:
Options
   Global
      Connections
      Storage Options
   Session
      Filters
      ListsTIA

mperemsky5 wrote:
Ok, I have many panels in the application. Each panel is a different layout and contains information pertinent to that specific feature.
Panel A = All Connection Information
Panel B = All Log File Information
Pancel C = All Proxy Information
If I click on node A in the JTree I want Panel A to be displayed on the RHS of the dialog box. If I click node B I want Panel B to be displayed on the RHS of the dialog box. Remember, all the Panels are different and have different inputs, so this is not simply a matter of having a single form on the RHS and updating values in the form.
I have added a mouse click listener to the JTree to retrieve which node of the tree has been clicked (still working on deciphering which node in the tree). When this listener is called, it needs to display the Panel associated with that node.
Since I want the overall dialog box to remain the same size (say 600 x 400), I need Panels A,B,... to be displayed in the same size area on the RHS of the dialog box (say 300 x 400). Do I need to create a Panel that is 300x400 and add A, B, ... to that panel to ensure that they all display in the same location/size in the dialog box.
If this is not clear, what part is unclear?Okay gotcha. That sounds like a job for CardLayout then. Check out the link I posted earlier. Also, the link I posted to the Tree tutorial shows you how to figure out which node was clicked.

Similar Messages

Help with JTree and JPanel (or JFrame)

Hi! I've an application that has JLabel, JTextField, JTree and JScrollPane.
The problem is that when I add the tree to the scrollpane and then add it to the frame (or panel), the tree is not displayed. The labels and textfields are there, but the tree is not. But, if I don't use the scroll, just add the tree, then the tree is visible.
Why is this happening?
Hope u can help me!

Please, helpppppppppppp!!!!!!!!!!!!!!!!!!!!!!!
:)

Focus Problem with JTree and Menus

Hi all,
I have a problem with focus when editing a JTree and selecting a menu. The problem occurs when the user single clicks on a node, invoking the countdown to edit. If the user quickly clicks on a menu item, the focus will go to the menu item, but then when the countdown finishes, the node now has keyboard focus.
Below is code to reproduce the problem. Click on the node, hover for a little bit, then quickly click on the menu item.
How would I go about fixing the problem? Thanks!
import java.awt.Container;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
public class MyTree extends JTree {
     public MyTree(DefaultTreeModel treemodel) {
          setModel(treemodel);
          setRootVisible(true);
     public static void main(String[] args) {
          JFrame frame = new JFrame();
          JMenuBar bar = new JMenuBar();
          JMenu menu = new JMenu("Test");
          JMenuItem item = new JMenuItem("Item");
          menu.add(item);
          bar.add(menu);
          frame.setJMenuBar(bar);
          Container contentPane = frame.getContentPane();
          contentPane.setLayout(new GridLayout(1, 2));
          DefaultMutableTreeNode root1 = new DefaultMutableTreeNode("Root");
          root1.add(new DefaultMutableTreeNode("Root2"));
          DefaultTreeModel model = new DefaultTreeModel(root1);
          MyTree tree1 = new MyTree(model);
          tree1.setEditable(true);
          tree1.setCellEditor(
               new ComponentTreeCellEditor(
                    tree1,
                    new ComponentTreeCellRenderer()));
          tree1.setRowHeight(0);
          contentPane.add(tree1);
          frame.pack();
          frame.show();
import java.awt.FlowLayout;
import java.util.EventObject;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JTree;
import javax.swing.tree.DefaultTreeCellEditor;
import javax.swing.tree.DefaultTreeCellRenderer;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeCellEditor;
import javax.swing.tree.TreeCellRenderer;
public class ComponentTreeCellEditor
     extends DefaultTreeCellEditor
     implements TreeCellEditor {
     private String m_oldValue;
     private TreeCellRenderer m_renderer = null;
     private DefaultTreeModel m_model = null;
     private JPanel m_display = null;
     private JTextField m_field = null;
     private JTree m_tree = null;
     public ComponentTreeCellEditor(
          JTree tree,
          DefaultTreeCellRenderer renderer) {
          super(tree, renderer);
          m_renderer = renderer;
          m_model = (DefaultTreeModel) tree.getModel();
          m_tree = tree;
          m_display = new JPanel(new FlowLayout(FlowLayout.LEFT));
          m_field = new JTextField();
          m_display.add(new JLabel("My Label "));
          m_display.add(m_field);
     public java.awt.Component getTreeCellEditorComponent(
          JTree tree,
          Object value,
          boolean isSelected,
          boolean expanded,
          boolean leaf,
          int row) {
          m_field.setText(value.toString());
          return m_display;
     public Object getCellEditorValue() {
          return m_field.getText();
      * The edited cell should always be selected.
      * @param anEvent the event that fired this function.
      * @return true, always.
     public boolean shouldSelectCell(EventObject anEvent) {
          return true;
      * Only edit immediately if the event is null.
      * @param event the event being studied
      * @return true if event is null, false otherwise.
     protected boolean canEditImmediately(EventObject event) {
          return (event == null);
}

You can provide a cell renderer to the JTree to paint the checkBox.
The following code checks or unchecks the box with each click also:
_tree.setCellRenderer(new DefaultTreeCellRenderer()
private JCheckBox checkBox = null;
public Component getTreeCellRendererComponent(JTree tree,
                                                Object value,
                                                boolean selected,
                                                boolean expanded,
                                                boolean leaf,
                                                int row,
                                                boolean hasFocus)
    // Each node will be drawn as a check box
    if (checkBox == null)
      checkBox = new JCheckBox();
      checkBox .setBackground(tree.getBackground());
    DefaultMutableTreeNode node = (DefaultMutableTreeNode)value;
    checkBox.setText(node.getUserObject().toString());
    checkBox.setSelected(selected);
    return checkBox;
});

Drag and Drop between JTree and another component

Hi,
I have searched the forum for answer to this question but am not sure I found something similar to this. So, please help me out on this.
I have a JTree and a JPanel, which basically shows images (as thumbnails) for the child nodes of one node in the tree heirarchy.
I need to be able to drag and drop components from the JPanel to the JTree and vice versa, and of course, when you drop them on the tree, they should go under the correct node.
I am using Swing 1.4.1, and have successfully implemented DnD in the JTree itself. But I am a little unclear about the DnD between the tree and the panel.
Would really appreciate if someone could throw some light on this.
Thanks a lot,
Sri.

Hi clairesheridan,
thanks for your response. Your answer would have helped me if I was using JDK 1.3 but I am try to use the Swing API in jdk1.4.1, in which you have to set a transferhandler etc.
Please let me know if you have any ideas or solutions.
Thanks,
sriharmya.

Location of node of JTree in JPanel?

Hello
does anyone know how I can retrieve the location (x and y) of a node of a JTree, which is in a JPanel?

Assuming your JPanel is the direct parent of your JTree and assuming you're asking for the location relative to the JPanel origin, this should do it.
Rectangle r = tree.getRowBounds(tree.getRowForPath(yourNodePath));
Point p = tree.getLocation();
r.x += p.x;
r.y += p.y;Simple enough to find in the API ;o)

What's difference between JPanel.remove(); and JPanel = null

nice day,
how can remove JPanel (including its JComponents), safe way, can you explain the difference between JPanel.remove () and JPanel = null,
1/ because if JPanel does not contain any static JComponents
2/ or any reference to static objects,
then works as well as JPanel.remove or JPanel = null,
or what and why preferred to avoid some action (to avoid to remove or to avoid to null)

mKorbel wrote:
nice day,
how can remove JPanel (including its JComponents), safe way, can you explain the difference between JPanel.remove () and JPanel = null, Remove the JPanel from the container it was part of and make sure you do not keep any references to it from your own classes. Don't make it any more difficult than it has to be.

One model for JTree and JTable

Hi.
Is it possible for a JTree and a JTable to share one model?
Thank you

Hope u r not using Comonent TreeTable
If u have Tree & Table different components, just want to have a common model then u can try this,
It is nothing but default implementation given in DefaultTableModel
public class MyTreeTableModel extends DefaultTreeModel implements TableModel, Serializable {
protected Vector dataVector;
/** List of listeners */
protected EventListenerList listenerList = new EventListenerList();
/** The <code>Vector</code> of column identifiers. */
protected Vector columnIdentifiers;
public MyTreeTableModel(TreeNode root) {
this(root, false);
// constructor for TreeModel only
public MyTreeTableModel(TreeNode root, boolean asksAllowsChildren) {
super(root, asksAllowsChildren);
// constructor for TableModel only
public MyTreeTableModel() {
this(0, 0);
private static Vector newVector(int size) {
Vector v = new Vector(size);
v.setSize(size);
return v;
// constructor for TableModel only
public MyTreeTableModel(int rowCount, int columnCount) {
this(newVector(columnCount), rowCount);
// constructor for TableModel only
public MyTreeTableModel(Vector columnNames, int rowCount) {
super(null);
setDataVector(newVector(rowCount), columnNames);
// constructor for TableModel only
public MyTreeTableModel(Object[] columnNames, int rowCount) {
this(convertToVector(columnNames), rowCount);
// constructor for TableModel only
public MyTreeTableModel(Vector data, Vector columnNames) {
super(null);
setDataVector(data, columnNames);
// constructor for TableModel only
public MyTreeTableModel(Object[][] data, Object[] columnNames) {
super(null);
setDataVector(data, columnNames);
* Returns a default name for the column using spreadsheet conventions:
* A, B, C, ... Z, AA, AB, etc. If <code>column</code> cannot be found,
* returns an empty string.
* @param column the column being queried
* @return a string containing the default name of <code>column</code>
private String getDefaultColumnName(int column) {
String result = "";
for (; column >= 0; column = column / 26 - 1) {
result = (char)((char)(column%26)+'A') + result;
return result;
* Returns a column given its name.
* Implementation is naive so this should be overridden if
* this method is to be called often. This method is not
* in the <code>TableModel</code> interface and is not used by the
* <code>JTable</code>.
* @param columnName string containing name of column to be located
* @return the column with <code>columnName</code>, or -1 if not found
public int findColumn(String columnName) {
for (int i = 0; i < getColumnCount(); i++) {
if (columnName.equals(getColumnName(i))) {
return i;
return -1;
* Returns <code>Object.class</code> regardless of <code>columnIndex</code>.
* @param columnIndex the column being queried
* @return the Object.class
public Class getColumnClass(int columnIndex) {
return Object.class;
// Managing Listeners
* Adds a listener to the list that's notified each time a change
* to the data model occurs.
* @param l the TableModelListener
public void addTableModelListener(TableModelListener l) {
listenerList.add(TableModelListener.class, l);
* Removes a listener from the list that's notified each time a
* change to the data model occurs.
* @param l the TableModelListener
public void removeTableModelListener(TableModelListener l) {
listenerList.remove(TableModelListener.class, l);
* Returns an array of all the table model listeners
* registered on this model.
* @return all of this model's <code>TableModelListener</code>s
* or an empty
* array if no table model listeners are currently registered
public TableModelListener[] getTableModelListeners() {
return (TableModelListener[])listenerList.getListeners(
TableModelListener.class);
// Fire methods
* Notifies all listeners that all cell values in the table's
* rows may have changed. The number of rows may also have changed
* and the <code>JTable</code> should redraw the
* table from scratch. The structure of the table (as in the order of the
* columns) is assumed to be the same.
public void fireTableDataChanged() {
fireTableChanged(new TableModelEvent(this));
* Notifies all listeners that the table's structure has changed.
* The number of columns in the table, and the names and types of
* the new columns may be different from the previous state.
* If the <code>JTable</code> receives this event and its
* <code>autoCreateColumnsFromModel</code>
* flag is set it discards any table columns that it had and reallocates
* default columns in the order they appear in the model. This is the
* same as calling <code>setModel(TableModel)</code> on the
* <code>JTable</code>.
public void fireTableStructureChanged() {
fireTableChanged(new TableModelEvent(this, TableModelEvent.HEADER_ROW));
* Notifies all listeners that rows in the range
* <code>[firstRow, lastRow]</code>, inclusive, have been inserted.
* @param firstRow the first row
* @param lastRow the last row
public void fireTableRowsInserted(int firstRow, int lastRow) {
fireTableChanged(new TableModelEvent(this, firstRow, lastRow,
TableModelEvent.ALL_COLUMNS, TableModelEvent.INSERT));
* Notifies all listeners that rows in the range
* <code>[firstRow, lastRow]</code>, inclusive, have been updated.
* @param firstRow the first row
* @param lastRow the last row
public void fireTableRowsUpdated(int firstRow, int lastRow) {
fireTableChanged(new TableModelEvent(this, firstRow, lastRow,
TableModelEvent.ALL_COLUMNS, TableModelEvent.UPDATE));
* Notifies all listeners that rows in the range
* <code>[firstRow, lastRow]</code>, inclusive, have been deleted.
* @param firstRow the first row
* @param lastRow the last row
public void fireTableRowsDeleted(int firstRow, int lastRow) {
fireTableChanged(new TableModelEvent(this, firstRow, lastRow,
TableModelEvent.ALL_COLUMNS, TableModelEvent.DELETE));
* Notifies all listeners that the value of the cell at
* <code>[row, column]</code> has been updated.
* @param row row of cell which has been updated
* @param column column of cell which has been updated
public void fireTableCellUpdated(int row, int column) {
fireTableChanged(new TableModelEvent(this, row, row, column));
* Forwards the given notification event to all
* <code>TableModelListeners</code> that registered
* themselves as listeners for this table model.
* @param e the event to be forwarded
public void fireTableChanged(TableModelEvent e) {
// Guaranteed to return a non-null array
Object[] listeners = listenerList.getListenerList();
// 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==TableModelListener.class) {
((TableModelListener)listeners[i+1]).tableChanged(e);
* Returns an array of all the objects currently registered
* as <code>FooListener</code>s
* upon this <code>AbstractTableModel</code>.
* <code>FooListener</code>s are registered using the
* <code>addFooListener</code> method.
* 
* You can specify the <code>listenerType</code> argument
* with a class literal,
* such as
* <code>FooListener.class</code>.
* For example, you can query a
* model <code>m</code>
* for its table model listeners with the following code:
* <pre>TableModelListener[] tmls = (TableModelListener[])(m.getListeners(TableModelListener.class));</pre>
* If no such listeners exist, this method returns an empty array.
* @param listenerType the type of listeners requested; this parameter
* should specify an interface that descends from
* <code>java.util.EventListener</code>
* @return an array of all objects registered as
* <code>FooListener</code>s on this component,
* or an empty array if no such
* listeners have been added
* @exception ClassCastException if <code>listenerType</code>
* doesn't specify a class or interface that implements
* <code>java.util.EventListener</code>
public EventListener[] getListeners(Class listenerType) {
return listenerList.getListeners(listenerType);
* Returns the <code>Vector</code> of <code>Vectors</code>
* that contains the table's
* data values. The vectors contained in the outer vector are
* each a single row of values. In other words, to get to the cell
* at row 1, column 5: 
* <code>((Vector)getDataVector().elementAt(1)).elementAt(5);</code>
* @return the vector of vectors containing the tables data values
public Vector getDataVector() {
return dataVector;
private static Vector nonNullVector(Vector v) {
return (v != null) ? v : new Vector();
* Replaces the current <code>dataVector</code> instance variable
* with the new Vector of rows, <code>dataVector</code>.
* <code>columnIdentifiers</code> are the names of the new
* columns. The first name in <code>columnIdentifiers</code> is
* mapped to column 0 in <code>dataVector</code>. Each row in
* <code>dataVector</code> is adjusted to match the number of
* columns in <code>columnIdentifiers</code>
* either by truncating the <code>Vector</code> if it is too long,
* or adding <code>null</code> values if it is too short.
* Note that passing in a <code>null</code> value for
* <code>dataVector</code> results in unspecified behavior,
* an possibly an exception.
* @param dataVector the new data vector
* @param columnIdentifiers the names of the columns
public void setDataVector(Vector dataVector, Vector columnIdentifiers) {
this.dataVector = nonNullVector(dataVector);
this.columnIdentifiers = nonNullVector(columnIdentifiers);
justifyRows(0, getRowCount());
fireTableStructureChanged();
* Replaces the value in the <code>dataVector</code> instance
* variable with the values in the array <code>dataVector</code>.
* The first index in the <code>Object[][]</code>
* array is the row index and the second is the column index.
* <code>columnIdentifiers</code> are the names of the new columns.
* @param dataVector the new data vector
* @param columnIdentifiers the names of the columns
public void setDataVector(Object[][] dataVector, Object[] columnIdentifiers) {
setDataVector(convertToVector(dataVector), convertToVector(columnIdentifiers));
* Equivalent to <code>fireTableChanged</code>.
* @param event the change event
public void newDataAvailable(TableModelEvent event) {
fireTableChanged(event);
// Manipulating rows
private void justifyRows(int from, int to) {
// Sometimes the MyTreeTableModel is subclassed
// instead of the AbstractTableModel by mistake.
// Set the number of rows for the case when getRowCount
// is overridden.
dataVector.setSize(getRowCount());
for (int i = from; i < to; i++) {
if (dataVector.elementAt(i) == null) {
dataVector.setElementAt(new Vector(), i);
((Vector)dataVector.elementAt(i)).setSize(getColumnCount());
* Ensures that the new rows have the correct number of columns.
* This is accomplished by using the <code>setSize</code> method in
* <code>Vector</code> which truncates vectors
* which are too long, and appends <code>null</code>s if they
* are too short.
* This method also sends out a <code>tableChanged</code>
* notification message to all the listeners.
* @param e this <code>TableModelEvent</code> describes
* where the rows were added.
* If <code>null</code> it assumes
* all the rows were newly added
public void newRowsAdded(TableModelEvent e) {
justifyRows(e.getFirstRow(), e.getLastRow() + 1);
fireTableChanged(e);
* Equivalent to <code>fireTableChanged</code>.
* @param event the change event
public void rowsRemoved(TableModelEvent event) {
fireTableChanged(event);
* Obsolete as of Java 2 platform v1.3. Please use <code>setRowCount</code> instead.
* Sets the number of rows in the model. If the new size is greater
* than the current size, new rows are added to the end of the model
* If the new size is less than the current size, all
* rows at index <code>rowCount</code> and greater are discarded. 
* @param rowCount the new number of rows
public void setNumRows(int rowCount) {
int old = getRowCount();
if (old == rowCount) {
return;
dataVector.setSize(rowCount);
if (rowCount <= old) {
fireTableRowsDeleted(rowCount, old-1);
else {
justifyRows(old, rowCount);
fireTableRowsInserted(old, rowCount-1);
* Sets the number of rows in the model. If the new size is greater
* than the current size, new rows are added to the end of the model
* If the new size is less than the current size, all
* rows at index <code>rowCount</code> and greater are discarded. 
public void setRowCount(int rowCount) {
setNumRows(rowCount);
* Adds a row to the end of the model. The new row will contain
* <code>null</code> values unless <code>rowData</code> is specified.
* Notification of the row being added will be generated.
* @param rowData optional data of the row being added
public void addRow(Vector rowData) {
insertRow(getRowCount(), rowData);
* Adds a row to the end of the model. The new row will contain
* <code>null</code> values unless <code>rowData</code> is specified.
* Notification of the row being added will be generated.
* @param rowData optional data of the row being added
public void addRow(Object[] rowData) {
addRow(convertToVector(rowData));
* Inserts a row at <code>row</code> in the model. The new row
* will contain <code>null</code> values unless <code>rowData</code>
* is specified. Notification of the row being added will be generated.
* @param row the row index of the row to be inserted
* @param rowData optional data of the row being added
* @exception ArrayIndexOutOfBoundsException if the row was invalid
public void insertRow(int row, Vector rowData) {
dataVector.insertElementAt(rowData, row);
justifyRows(row, row+1);
fireTableRowsInserted(row, row);
* Inserts a row at <code>row</code> in the model. The new row
* will contain <code>null</code> values unless <code>rowData</code>
* is specified. Notification of the row being added will be generated.
* @param row the row index of the row to be inserted
* @param rowData optional data of the row being added
* @exception ArrayIndexOutOfBoundsException if the row was invalid
public void insertRow(int row, Object[] rowData) {
insertRow(row, convertToVector(rowData));
private static int gcd(int i, int j) {
return (j == 0) ? i : gcd(j, i%j);
private static void rotate(Vector v, int a, int b, int shift) {
int size = b - a;
int r = size - shift;
int g = gcd(size, r);
for(int i = 0; i < g; i++) {
int to = i;
Object tmp = v.elementAt(a + to);
for(int from = (to + r) % size; from != i; from = (to + r) % size) {
v.setElementAt(v.elementAt(a + from), a + to);
to = from;
v.setElementAt(tmp, a + to);
* Moves one or more rows from the inlcusive range <code>start</code> to
* <code>end</code> to the <code>to</code> position in the model.
* After the move, the row that was at index <code>start</code>
* will be at index <code>to</code>.
* This method will send a <code>tableChanged</code> notification
* message to all the listeners. 
* <pre>
* Examples of moves:
* 
* 1. moveRow(1,3,5);
* a|B|C|D|e|f|g|h|i|j|k - before
* a|e|f|g|h|B|C|D|i|j|k - after
* 
* 2. moveRow(6,7,1);
* a|b|c|d|e|f|G|H|i|j|k - before
* a|G|H|b|c|d|e|f|i|j|k - after
* 
* </pre>
* @param start the starting row index to be moved
* @param end the ending row index to be moved
* @param to the destination of the rows to be moved
* @exception ArrayIndexOutOfBoundsException if any of the elements
* would be moved out of the table's range
public void moveRow(int start, int end, int to) {
int shift = to - start;
int first, last;
if (shift < 0) {
first = to;
last = end;
else {
first = start;
last = to + end - start;
rotate(dataVector, first, last + 1, shift);
fireTableRowsUpdated(first, last);
* Removes the row at <code>row</code> from the model. Notification
* of the row being removed will be sent to all the listeners.
* @param row the row index of the row to be removed
* @exception ArrayIndexOutOfBoundsException if the row was invalid
public void removeRow(int row) {
dataVector.removeElementAt(row);
fireTableRowsDeleted(row, row);
// Manipulating columns
* Replaces the column identifiers in the model. If the number of
* <code>newIdentifier</code>s is greater than the current number
* of columns, new columns are added to the end of each row in the model.
* If the number of <code>newIdentifier</code>s is less than the current
* number of columns, all the extra columns at the end of a row are
* discarded. 
* @param newIdentifiers vector of column identifiers. If
* <code>null</code>, set the model
* to zero columns
public void setColumnIdentifiers(Vector columnIdentifiers) {
setDataVector(dataVector, columnIdentifiers);
* Replaces the column identifiers in the model. If the number of
* <code>newIdentifier</code>s is greater than the current number
* of columns, new columns are added to the end of each row in the model.
* If the number of <code>newIdentifier</code>s is less than the current
* number of columns, all the extra columns at the end of a row are
* discarded. 
* @param newIdentifiers array of column identifiers.
* If <code>null</code>, set
* the model to zero columns
public void setColumnIdentifiers(Object[] newIdentifiers) {
setColumnIdentifiers(convertToVector(newIdentifiers));
* Sets the number of columns in the model. If the new size is greater
* than the current size, new columns are added to the end of the model
* with <code>null</code> cell values.
* If the new size is less than the current size, all columns at index
* <code>columnCount</code> and greater are discarded.
* @param columnCount the new number of columns in the model
public void setColumnCount(int columnCount) {
columnIdentifiers.setSize(columnCount);
justifyRows(0, getRowCount());
fireTableStructureChanged();
* Adds a column to the model. The new column will have the
* identifier <code>columnName</code>, which may be null. This method
* will send a
* <code>tableChanged</code> notification message to all the listeners.
* This method is a cover for <code>addColumn(Object, Vector)</code> which
* uses <code>null</code> as the data vector.
* @param columnName the identifier of the column being added
public void addColumn(Object columnName) {
addColumn(columnName, (Vector)null);
* Adds a column to the model. The new column will have the
* identifier <code>columnName</code>, which may be null.
* <code>columnData</code> is the
* optional vector of data for the column. If it is <code>null</code>
* the column is filled with <code>null</code> values. Otherwise,
* the new data will be added to model starting with the first
* element going to row 0, etc. This method will send a
* <code>tableChanged</code> notification message to all the listeners.
* @param columnName the identifier of the column being added
* @param columnData optional data of the column being added
public void addColumn(Object columnName, Vector columnData) {
columnIdentifiers.addElement(columnName);
if (columnData != null) {
int columnSize = columnData.size();
if (columnSize > getRowCount()) {
dataVector.setSize(columnSize);
justifyRows(0, getRowCount());
int newColumn = getColumnCount() - 1;
for(int i = 0; i < columnSize; i++) {
Vector row = (Vector)dataVector.elementAt(i);
row.setElementAt(columnData.elementAt(i), newColumn);
else {
justifyRows(0, getRowCount());
fireTableStructureChanged();
* Adds a column to the model. The new column will have the
* identifier <code>columnName</code>. <code>columnData</code> is the
* optional array of data for the column. If it is <code>null</code>
* the column is filled with <code>null</code> values. Otherwise,
* the new data will be added to model starting with the first
* element going to row 0, etc. This method will send a
* <code>tableChanged</code> notification message to all the listeners.
public void addColumn(Object columnName, Object[] columnData) {
addColumn(columnName, convertToVector(columnData));
// Implementing the TableModel interface
* Returns the number of rows in this data table.
* @return the number of rows in the model
public int getRowCount() {
return dataVector.size();
* Returns the number of columns in this data table.
* @return the number of columns in the model
public int getColumnCount() {
return columnIdentifiers.size();
* Returns the column name.
* @return a name for this column using the string value of the
* appropriate member in <code>columnIdentifiers</code>.
* If <code>columnIdentifiers</code> does not have an entry
* for this index, returns the default
* name provided by the superclass
public String getColumnName(int column) {
Object id = null;
// This test is to cover the case when
// getColumnCount has been subclassed by mistake ...
if (column < columnIdentifiers.size()) {
id = columnIdentifiers.elementAt(column);
return (id == null) ? getDefaultColumnName(column)
: id.toString();
* Returns true regardless of parameter values.
* @param row the row whose value is to be queried
* @param column the column whose value is to be queried
* @return true
public boolean isCellEditable(int row, int column) {
return true;
* Returns an attribute value for the cell at <code>row</code>
* and <code>column</code>.
* @param row the row whose value is to be queried
* @param column the column whose value is to be queried
* @return the value Object at the specified cell
* @exception ArrayIndexOutOfBoundsException if an invalid row or
* column was given
public Object getValueAt(int row, int column) {
Vector rowVector = (Vector)dataVector.elementAt(row);
return rowVector.elementAt(column);
* Sets the object value for the cell at <code>column</code> and
* <code>row</code>. <code>aValue</code> is the new value. This method
* will generate a <code>tableChanged</code> notification.
* @param aValue the new value; this can be null
* @param row the row whose value is to be changed
* @param column the column whose value is to be changed
* @exception ArrayIndexOutOfBoundsException if an invalid row or
* column was given
public void setValueAt(Object aValue, int row, int column) {
Vector rowVector = (Vector)dataVector.elementAt(row);
rowVector.setElementAt(aValue, column);
fireTableCellUpdated(row, column);
// Protected Methods
* Returns a vector that contains the same objects as the array.
* @param anArray the array to be converted
* @return the new vector; if <code>anArray</code> is <code>null</code>,
* returns <code>null</code>
protected static Vector convertToVector(Object[] anArray) {
if (anArray == null) {
return null;
Vector v = new Vector(anArray.length);
for (int i=0; i < anArray.length; i++) {
v.addElement(anArray[i]);
return v;
* Returns a vector of vectors that contains the same objects as the array.
* @param anArray the double array to be converted
* @return the new vector of vectors; if <code>anArray</code> is
* <code>null</code>, returns <code>null</code>
protected static Vector convertToVector(Object[][] anArray) {
if (anArray == null) {
return null;
Vector v = new Vector(anArray.length);
for (int i=0; i < anArray.length; i++) {
v.addElement(convertToVector(anArray[i]));
return v;

Drag and Drop between JTree and Labels in 2 different panes

Hi,
I am using JDK 1.4.1 and am trying to implement Drag n Drop between a JTree and JLabels with ImageIcons, both on different panes.
I got the DnD working fine on the tree. but i cant get to drag and drop the label from the other pane, on the Jtree as a node. I am getting confused with the DataFlavors, and also wonder if there is something else that i have to do for DnD between 2 panes. Can someone give me any leads on this, please? The Panes I am talking about are splitpanes.
thanks,
Sri.

hey thanks Dennis!! I was hoping you would respond to my question, as I have seen a lot of your replies. yes, the example you gave would be helpful. but i am trying to implement this in 1.4.1, with the new drag and drop in swing. and i am getting confused wiht theh data flavors etc.
my problem at hand is :
I have a tree on the left pane. i can drag and drop the nodes on the tree itself. (i already did that...no problem). I have Jlabels with imageicons (actually wrapper classes with labels and imageicons) on the right pane. i have to be able to drag these labels to the tree such that they form a node.
I have one class the NodeSelection class which extends TransferHandler and implements Transferable. i was able to do DnD for the tree using this. I customized the importData method in this.I thought that i can just use the same class to create the transferhandler and transferable, and just use a different implementation for the importData method if the data being dragged is from the label.
well, my thoughts and ideas were ok...but i can implement it...so they must be wrong ;-)
Can u please suggest another way to do this. I have a deadline to meet and am stuck here :-( any suggestions or tips or hints would be very helpful and appreciated!!
Thanks,
Sri.

How i can enter information from Database to jtree and update it

How i can enter information from Database to jtree and update it

Is the memory cache enabled (about:cache)? 
You can open about: pages via the location bar like you open a website.
*http://kb.mozillazine.org/browser.cache.memory.enable

Resizing JFrames and JPanels !!!

Hi Experts,
I had one JFrame in which there are three objects, these objects are of those classes which extends JPanel. So, in short in one JFrame there are three JPanels.
My all JPanels using GridBagLayout and JFrame also using same. When I resize my JFrame ,it also resize my all objects.
My Problem is how should i allow user to resize JPanels in JFrame also?? and if user is resizing one JPanel than other should adjust according to new size ...
Plese guide me, how should i do this ...
Thanknig Java Community,
Dhwanit Shah

Hey there, thanx for your kind intereset.
Here is sample code .
In which there is JFrame, JPanel and in JPanel ther is one JButton.Jpanel is added to JFrame.
I want to resize JPanel within JFrame,I am able to do resize JFrame and JPanel sets accroding to it.
import java.awt.*;
import javax.swing.*;
import com.borland.jbcl.layout.*;
public class FramePanel extends JFrame {
JPanel contentPane;
GridBagLayout gridBagLayout1 = new GridBagLayout();
public FramePanel() {
try {
jbInit();
catch(Exception e) {
e.printStackTrace();
public static void main(String[] args) {
FramePanel framePanel = new FramePanel();
private void jbInit() throws Exception {
contentPane = (JPanel) this.getContentPane();
contentPane.setLayout(gridBagLayout1);
this.setSize(new Dimension(296, 284));
this.setTitle("Frame and Panel Together");
MyPanel myPanel = new MyPanel();
this.getContentPane().add(myPanel);
this.setVisible(true);
class MyPanel extends JPanel {
public MyPanel() {
this.setSize(200,200);
this.setLayout(new FlowLayout());
this.setBackground(Color.black);
this.setVisible(true);
this.add(new JButton("Dhwanit Shah"));
I think i might explained my problem
Dhwanit Shah
[email protected]

Catch the image of JTree and save it as a file

There is an JTree and it has a few nodes.
And there, I want to capture both the image of JTree and
the images of it's child nodes as they show in screen.
if possible, I want to capture image of all expanded nodes in tree and
save them as jpg file.
I try to capture the Image of JTree from JTree.createImage() method.
and I also tried to capture the images of child nodes
from JTree.getComponents() and capture images all of child nodes as they were.
I,however,get to know the method
Component.createImage() doesn't return the image that shows in screen as it was.
could anybody tell me the answer?

Hi,
don't know if I got you right, but what you want is a "screenshot" of the JTree, right ?
Try to paint the JTree in a BufferedImage and encode this as JPEG or whatever.
BufferedImage theImage = new BufferedImage(
      owner.getWidth(), owner.getHeight(), BufferedImage.TYPE_INT_RGB);
      Graphics g = theImage.createGraphics();
      g.setClip( 0, 0, owner.getWidth(), owner.getHeight());
      owner.paint( g);owner is your JTree or any other component you want.
Hope that helped.

How to retrieve the nodes from the Database on JTree and many more

I am facing a problem with JTree. I want to retrieve all the nodes from the MS-Access database on the Frame(i.e. Frame will display the JTree), then I also want to perform function like Edit, insert , delete and Drag and Drop opeartion on the JTree and the database should also updated accordingly.
So, if you have any idea or if you have some code to look for then please send it to me.

I am facing a problem with JTree. I want to retrieve all the nodes from the MS-Access database on the Frame(i.e. Frame will display the JTree), then I also want to perform function like Edit, insert , delete and Drag and Drop opeartion on the JTree and the database should also updated accordingly
pls give me code

Inserting a Gui program using JFrames and JPanel

I'm trying to insert a chat program into a game that I've created! The chat program is using JFrames and JPanels. I want to insert this into a GridLayout and Panel. How can I go about doing this?

whatever is in the frame's contentPane now, you add to a separate JPanel.
you also add your chat stuff to the separate panel
the separate panel is added to the frame as the content pane

JTree and JButton in node.

Helo.
I've a question regarding JTree component. I was wondering if it is possible at all.
I want to build JTree component with JButton(JPanel) in each node, for example:
RootNode
|
---String [JButton][JButton]
|
---String [JButton][JButton]
Is there possibility to put JPanel into children node.
Maybe anyone did do this before?
Thanks in advance for any help.
Regards

This is possible. You'll have to take a look at TreeCellRenderer and TreeCellEditor, and maybe the tutorial at http://java.sun.com/docs/books/tutorial/uiswing/components/tree.html . Basically, both interfaces allow you to return arbitrary components for rendering / editing tree nodes. The default implementation is based on JLabels, but you can use complex panels with multiple child components as well.

JTree and JComboBox Topic

how can i add a JTree to a JComboBox?
Also i should be able to expand the JTree by clicking at the nodes..

what do you want to do.
A tree to appear when you press the button on the combo box?
or do you want a tree to appear as one of the items in the list.
Onve I wanted to create a multi column combo box.
I tried lots of things to make it a subclass of JComboBox but the implementation of the popup list of the combo box highly depend on the Look And Feel so I had to write my own combo box combining a JTextArea and a JButton in a JPanel.
I made the popup by putting a JTable inside a JScrollPane inside a JPanel inside a JPopupMenu

JTree and JPanel

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