Demonstrates how to add copy and drag support to a Swing component with TransferHandler : Drag Drop « Swing « Java Tutorial

 * Copyright (c) 2004 David Flanagan.  All rights reserved.
 * This code is from the book Java Examples in a Nutshell, 3nd Edition.
 * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
 * You may study, use, and modify it for any non-commercial purpose,
 * including teaching and use in open-source projects.
 * You may distribute it non-commercially as long as you retain this notice.
 * For a commercial use license, or to purchase the book, 
 * please visit

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.text.DateFormat;
import java.util.Date;

import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JLabel;
import javax.swing.KeyStroke;
import javax.swing.Timer;
import javax.swing.TransferHandler;
import javax.swing.border.LineBorder;

 * A custom Swing component that displays a simple digital clock. Demonstrates
 * how to add copy and drag support to a Swing component with TransferHandler.
public class DigitalClock extends JLabel {
  DateFormat format; // How to display the time in string form

  int updateFrequency; // How often to update the time (in milliseconds)

  Timer timer; // Triggers repeated updates to the clock

  public DigitalClock() {
    // Set default values for our properties
    setFormat(DateFormat.getTimeInstance(DateFormat.MEDIUM, getLocale()));
    setUpdateFrequency(1000); // Update once a second

    // Specify a Swing TransferHandler object to do the dirty work of
    // copy-and-paste and drag-and-drop for us. This one will transfer
    // the value of the "time" property. Since this property is read-only
    // it will allow drags but not drops.
    setTransferHandler(new TransferHandler("time"));

    // Since JLabel does not normally support drag-and-drop, we need an
    // event handler to detect a drag and start the transfer.
    addMouseMotionListener(new MouseMotionAdapter() {
      public void mouseDragged(MouseEvent e) {
        getTransferHandler().exportAsDrag(DigitalClock.this, e, TransferHandler.COPY);

    // Before we can have a keyboard binding for a Copy command,
    // the component needs to be able to accept keyboard focus.
    // Request focus when we're clicked on
    addMouseListener(new MouseAdapter() {
      public void mouseClicked(MouseEvent e) {
    // Use a LineBorder to indicate when we've got the keyboard focus
    addFocusListener(new FocusListener() {
      public void focusGained(FocusEvent e) {

      public void focusLost(FocusEvent e) {

    // Now bind the Ctrl-C keystroke to a "Copy" command.
    InputMap im = new InputMap();
    im.put(KeyStroke.getKeyStroke(KeyEvent.VK_C, InputEvent.CTRL_MASK), "Copy");
    setInputMap(WHEN_FOCUSED, im);

    // And bind the "Copy" command to a pre-defined Action that performs
    // a copy using the TransferHandler we've installed.
    ActionMap am = new ActionMap();
    am.put("Copy", TransferHandler.getCopyAction());

    // Create a javax.swing.Timer object that will generate ActionEvents
    // to tell us when to update the displayed time. Every updateFrequency
    // milliseconds, this timer will cause the actionPerformed() method
    // to be invoked. (For non-GUI applications, see java.util.Timer.)
    timer = new Timer(updateFrequency, new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        setText(getTime()); // set label to current time string
    timer.setInitialDelay(0); // Do the first update immediately
    timer.start(); // Start timing now!

  // Return the current time as a String.
  // This is the property accessor method used by the TransferHandler.
  // Since there is a getter, but no setter, the TransferHandler will
  // reject any attempts to drop data on us.
  public String getTime() {
    // Use the DateFormat object to convert current time to a string
    return format.format(new Date());

  // Here are two related property setter methods
  public void setFormat(DateFormat format) {
    this.format = format;

  public void setUpdateFrequency(int ms) {
    this.updateFrequency = ms;

14.112.Drag Drop
14.112.1.Basic drag and drop
14.112.2.Dragging Text from a JLabelDragging Text from a JLabel
14.112.3.Drag-and-Drop Support for ImagesDrag-and-Drop Support for Images
14.112.4.Drag and drop icons: use an icon property.
14.112.5.implements DragGestureListener, Transferable
14.112.6.Dragging and dropping text between a text area, a list, and a tableDragging and dropping text between a text area, a list, and a table
14.112.7.Drag and drop between JTextArea and JTextField
14.112.8.Transfer both Text and Color between JTextField and JTextArea
14.112.9.Drag and drop between JList and JTextField
14.112.13.Set tree DropMode to DropMode.USE_SELECTION
14.112.14.Set tree drag mode to DropMode.ON
14.112.15.Set tree drag mode to DropMode.INSERT
14.112.16.Set tree drag mode to DropMode.ON_OR_INSERT
14.112.17.Choose Drop Action
14.112.18.Various drop actions
14.112.19.JTable drag and drop
14.112.20.Create a drag source a drop target and a transferable object.
14.112.21.Making a Component Draggable
14.112.22.Detect a drag initiating gesture in your application
14.112.23.Illustrates cut, copy, paste and drag and drop using three instances of JList
14.112.24.Location sensitive drag and drop
14.112.25.Demonstration of the top-level TransferHandler support on JFrame
14.112.26.Drag-and-Drop customization: drag the foreground color from the first label and drop it as the background color into the second one
14.112.27.Demonstrates how to add copy and drag support to a Swing component with TransferHandler
14.112.28.ScribblePane allows individual PolyLine lines to be selected, cut, copied, pasted, dragged, and dropped
14.112.29.Built-in drag and drop support: utilize a TransferHandler class
14.112.30.DND Drag and drop List