Need help .. JTable problem!!!!!

Question

Is there any way to provide drag n drop feature within Jtable cells ....
What I want to do is that ... I shud be able to drag a JTable cell to another JTable cell and the values of those two cell should interchange ....
Is this even possible ??? Please help me as I m new to Java
Thanx alot....

Answer 1

Plus I have one more problem the column headers arnt appearing ..... So please help me ..... I need two things to be done ....
1) Populate the tables using vectors, so that only that no of rows appear which are in table of my database ..
2) Column headers shud show up...
Here's my code ...
* Drag.java
package test;
import javax.swing.*;
import java.awt.Dimension;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.table.*;
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.dnd.*;
import java.awt.event.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;
public class Drag extends javax.swing.JFrame {
     private String url = "jdbc:odbc:FAMS";
    private Connection con;
    private Statement stmt;
    private Map<String, Color> colormap = new HashMap<String, Color>();
    public void populate()
    try {
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
        } catch(java.lang.ClassNotFoundException e) {
            System.err.print("ClassNotFoundException: ");
            System.err.println(e.getMessage());
           String query = "SELECT * FROM SubAllot";
        /* First clear the JTable */
        clearTable();
        /* get a handle for the JTable */
        javax.swing.table.TableModel model = table.getModel();
        int r = 0;
        try {
            /* connect to the database */
            con = DriverManager.getConnection(url, "", "");
            stmt = con.createStatement();
            /* run the Query getting the results into rs */
               ResultSet rs = stmt.executeQuery(query);
               while ((rs.next()) ) {
                    /* for each row get the fields
                       note the use of Object - necessary
                       to put the values into the JTable */
                   Object nm = rs.getObject(1);
                   Object sup = rs.getObject(2);
                   Object pri = rs.getObject(3);
                   Object sal = rs.getObject(4);
                   Object tot = rs.getObject(5);
                   model.setValueAt(nm, r, 0);
                   model.setValueAt(sup, r, 1);
                   model.setValueAt(pri, r, 2);
                   model.setValueAt(sal, r, 3);
                   model.setValueAt(tot, r, 4);
                   r++;
            stmt.close();
            con.close();
        } catch(SQLException ex) {
            System.err.println("SQLException: " + ex.getMessage());
       private void clearTable(){
        int numRows = table.getRowCount();
        int numCols = table.getColumnCount();
        javax.swing.table.TableModel model = table.getModel();
        for (int i=0; i < numRows; i++) {
            for (int j=0; j < numCols; j++) {
                model.setValueAt(null, i, j);
          private void writeTable(){
         /* First clear the table */
         emptyTable();
         Statement insertRow;// = con.prepareStatement(
         String baseString = "INSERT INTO SubAllot " +
                                    "VALUES ('";
         String insertString;
        int numRows = table.getRowCount();
        javax.swing.table.TableModel model = table.getModel();
       /* Integer sup, sal, tot;
        Double pri;
        Object o;
        try {
            /* connect to the database */
            con = DriverManager.getConnection(url, "", "");
             for (int r=0; r < numRows; r++) {
                  if (model.getValueAt(r, 0) != null){
                       insertString = baseString + model.getValueAt(r, 0)+"','";
                       insertString = insertString + model.getValueAt(r, 1)+"','";
                       insertString = insertString + model.getValueAt(r, 2)+"','";
                       insertString = insertString + model.getValueAt(r, 3)+"','";
                       insertString = insertString + model.getValueAt(r, 4)+"');";
                       System.out.println(insertString);
                      insertRow = con.createStatement();
                       insertRow.executeUpdate(insertString);
                       System.out.println("Writing Row " + r);
            insertRow.close();
            con.close();
        } catch(SQLException ex) {
            System.err.println("SQLException: " + ex.getMessage());
       // clearTable();
       private void emptyTable(){
         /* Define the SQL Query to get all data from the database table */
        String query = "DELETE * FROM SubAllot";
        try {
            /* connect to the database */
            con = DriverManager.getConnection(url, "", "");
            stmt = con.createStatement();
            /* run the Query */
               stmt.executeUpdate(query);
            stmt.close();
            con.close();
        } catch(SQLException ex) {
            System.err.println("SQLException: " + ex.getMessage());
           abstract class StringTransferHandler extends TransferHandler {
        public int dropAction;
        protected abstract String exportString(final JComponent c);
        protected abstract void importString(final JComponent c, final String str);
        @Override
        protected Transferable createTransferable(final JComponent c) {
            return new StringSelection(exportString(c));
        @Override
        public int getSourceActions(final JComponent c) {
            return MOVE;
        @Override
        public boolean importData(final JComponent c, final Transferable t) {
            if (canImport(c, t.getTransferDataFlavors())) {
                try {
                    String str = (String) t.getTransferData(DataFlavor.stringFlavor);
                    importString(c, str);
                    return true;
                } catch (UnsupportedFlavorException ufe) {
                } catch (IOException ioe) {
            return false;
        @Override
        public boolean canImport(final JComponent c, final DataFlavor[] flavors) {
            for (int ndx = 0; ndx < flavors.length; ndx++) {
                if (DataFlavor.stringFlavor.equals(flavors[ndx])) {
                    return true;
            return false;
    class TableTransferHandler extends StringTransferHandler {
        private int dragRow;
        private int[] dragColumns;
        private BufferedImage[] image;
        private int row;
        private int[] columns;
        public JTable target;
        private Map<String, Color> colormap;
        private TableTransferHandler(final Map<String, Color> colormap) {
            this.colormap = colormap;
        @Override
        protected Transferable createTransferable(final JComponent c) {
            JTable table = (JTable) c;
            dragRow = table.getSelectedRow();
            dragColumns = table.getSelectedColumns();
            createDragImage(table);
            return new StringSelection(exportString(c));
        protected String exportString(final JComponent c) {
            JTable table = (JTable) c;
            row = table.getSelectedRow();
            columns = table.getSelectedColumns();
            StringBuffer buff = new StringBuffer();
            colormap.clear();
            for (int j = 0; j < columns.length; j++) {
                Object val = table.getValueAt(row, columns[j]);
                buff.append(val == null ? "" : val.toString());
                if (j != columns.length - 1) {
                    buff.append(",");
                colormap.put(row+","+columns[j], Color.LIGHT_GRAY);
            table.repaint();
            return buff.toString();
        protected void importString(final JComponent c, final String str) {
            target = (JTable) c;
            DefaultTableModel model = (DefaultTableModel) target.getModel();
            String[] values = str.split("\n");
            int colCount = target.getSelectedColumn();
            int max = target.getColumnCount();
            for (int ndx = 0; ndx < values.length; ndx++) {
                String[] data = values[ndx].split(",");
                for (int i = 0; i < data.length; i++) {
                    String string = data;
if(colCount < max){
String val = (String) model.getValueAt(target.getSelectedRow(), colCount);
model.setValueAt(string, target.getSelectedRow(), colCount);
model.setValueAt(val, dragRow, dragColumns[i]);
colCount++;
public BufferedImage[] getDragImage() {
return image;
private void createDragImage(final JTable table) {
if (dragColumns != null) {
try {
image = new BufferedImage[dragColumns.length];
for (int i = 0; i < dragColumns.length; i++) {
Rectangle cellBounds = table.getCellRect(dragRow, i, true);
TableCellRenderer r = table.getCellRenderer(dragRow, i);
DefaultTableModel m = (DefaultTableModel) table.getModel();
JComponent lbl = (JComponent) r.getTableCellRendererComponent(table,
table.getValueAt(dragRow, dragColumns[i]), false, false, dragRow, i);
lbl.setBounds(cellBounds);
BufferedImage img = new BufferedImage(lbl.getWidth(), lbl.getHeight(),
BufferedImage.TYPE_INT_ARGB_PRE);
Graphics2D graphics = img.createGraphics();
graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.6f));
lbl.setBorder(BorderFactory.createLineBorder(Color.LIGHT_GRAY));
lbl.paint(graphics);
graphics.dispose();
image[i] = img;
} catch (RuntimeException re) {
class TableDropTarget extends DropTarget {
private Insets autoscrollInsets = new Insets(20, 20, 20, 20);
private Rectangle rect2D = new Rectangle();
private TableTransferHandler handler;
public TableDropTarget(final TableTransferHandler h) {
super();
this.handler = h;
@Override
public void dragOver(final DropTargetDragEvent dtde) {
handler.dropAction = dtde.getDropAction();
JTable table = (JTable) dtde.getDropTargetContext().getComponent();
Point location = dtde.getLocation();
int row = table.rowAtPoint(location);
int column = table.columnAtPoint(location);
table.changeSelection(row, column, false, false);
paintImage(table, location);
autoscroll(table, location);
super.dragOver(dtde);
public void dragExit(final DropTargetDragEvent dtde) {
clearImage((JTable) dtde.getDropTargetContext().getComponent());
super.dragExit(dtde);
@Override
public void drop(final DropTargetDropEvent dtde) {
Transferable data = dtde.getTransferable();
JTable table = (JTable) dtde.getDropTargetContext().getComponent();
clearImage(table);
handler.importData(table, data);
super.drop(dtde);
private final void paintImage(final JTable table, final Point location) {
Point pt = new Point(location);
BufferedImage[] image = handler.getDragImage();
if (image != null) {
table.paintImmediately(rect2D.getBounds());
rect2D.setLocation(pt.x - 15, pt.y - 15);
int wRect2D = 0;
int hRect2D = 0;
for (int i = 0; i < image.length; i++) {
table.getGraphics().drawImage(image[i], pt.x - 15, pt.y - 15, table);
pt.x += image[i].getWidth();
if (hRect2D < image[i].getHeight()) {
hRect2D = image[i].getHeight();
wRect2D += image[i].getWidth();
rect2D.setSize(wRect2D, hRect2D);
private final void clearImage(final JTable table) {
table.paintImmediately(rect2D.getBounds());
private Insets getAutoscrollInsets() {
return autoscrollInsets;
private void autoscroll(final JTable table, final Point cursorLocation) {
Insets insets = getAutoscrollInsets();
Rectangle outer = table.getVisibleRect();
Rectangle inner = new Rectangle(outer.x + insets.left,
outer.y + insets.top,
outer.width - (insets.left + insets.right),
outer.height - (insets.top + insets.bottom));
if (!inner.contains(cursorLocation)) {
Rectangle scrollRect = new Rectangle(cursorLocation.x - insets.left,
cursorLocation.y - insets.top,
insets.left + insets.right,
insets.top + insets.bottom);
table.scrollRectToVisible(scrollRect);
/** Creates new form Drag */
public Drag() {
initComponents();
populate();
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jScrollPane1 = new javax.swing.JScrollPane();
table = new javax.swing.JTable();
jButton1 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
table.setModel(new javax.swing.table.DefaultTableModel(
new Object [][] {
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null},
{null, null, null, null, null}
new String [] {
"Title 1", "Title 2", "Title 3", "Title 4", "Title 5"
Class[] types = new Class [] {
java.lang.Integer.class, java.lang.String.class, java.lang.String.class, java.lang.String.class, java.lang.String.class
public Class getColumnClass(int columnIndex) {
return types [columnIndex];
jScrollPane1.setViewportView(table);
table.getTableHeader().setReorderingAllowed(false);
table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
table.setCellSelectionEnabled(true);
table.setRowHeight(23);
table.setDragEnabled(true);
TableTransferHandler th = new TableTransferHandler(colormap);
table.setTransferHandler(th);
table.setDropTarget(new TableDropTarget(th));
table.setTableHeader(null);
jButton1.setText("UPDATE");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 452, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(jButton1)
.addContainerGap(15, Short.MAX_VALUE))
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 348, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGap(80, 80, 80)
.addComponent(jButton1)))
.addContainerGap(14, Short.MAX_VALUE))
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
writeTable(); // TODO add your handling code here:
* @param args the command line arguments
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Drag().setVisible(true);
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTable table;
// End of variables declaration