Date combo box

import java.awt.*;
import java.awt.event.*;
import java.util.Calendar;
import java.text.SimpleDateFormat;

import javax.swing.*;
import javax.swing.event.PopupMenuListener;
import javax.swing.event.PopupMenuEvent;
import javax.swing.plaf.ComboBoxUI;
import javax.swing.plaf.basic.ComboPopup;
import javax.swing.plaf.metal.MetalComboBoxUI;
import javax.swing.border.Border;
import javax.swing.border.EtchedBorder;
import javax.swing.border.EmptyBorder;

import com.sun.java.swing.plaf.motif.MotifComboBoxUI;
import com.sun.java.swing.plaf.windows.WindowsComboBoxUI;


public class DateComboBox extends JComboBox {

protected SimpleDateFormat dateFormat = new SimpleDateFormat("MMM d, yyyy");
public void setDateFormat(SimpleDateFormat dateFormat) {
this.dateFormat = dateFormat;
}
public void setSelectedItem(Object item) {
// Could put extra logic here or in renderer when item is instanceof Date, Calendar, or String
// Dont keep a list ... just the currently selected item
removeAllItems(); // hides the popup if visible
addItem(item);
super.setSelectedItem(item);
}

public void updateUI() {
ComboBoxUI cui = (ComboBoxUI) UIManager.getUI(this);
if (cui instanceof MetalComboBoxUI) {
cui = new MetalDateComboBoxUI();
} else if (cui instanceof MotifComboBoxUI) {
cui = new MotifDateComboBoxUI();
} else if (cui instanceof WindowsComboBoxUI) {
cui = new WindowsDateComboBoxUI();
}
setUI(cui);
}


class MetalDateComboBoxUI extends MetalComboBoxUI {
protected ComboPopup createPopup() {
return new DatePopup( comboBox );
}
}

class WindowsDateComboBoxUI extends WindowsComboBoxUI {
protected ComboPopup createPopup() {
return new DatePopup( comboBox );
}
}

class MotifDateComboBoxUI extends MotifComboBoxUI {
protected ComboPopup createPopup() {
return new DatePopup( comboBox );
}
}



class DatePopup implements ComboPopup, MouseMotionListener,
MouseListener, KeyListener, PopupMenuListener {

protected JComboBox comboBox;
protected Calendar calendar;
protected JPopupMenu popup;
protected JLabel monthLabel;
protected JPanel days = null;
protected SimpleDateFormat monthFormat = new SimpleDateFormat("MMM yyyy");

protected Color selectedBackground;
protected Color selectedForeground;
protected Color background;
protected Color foreground;

public DatePopup(JComboBox comboBox) {
this.comboBox = comboBox;
calendar = Calendar.getInstance();
//String[] dts = {dt};
int yr = calendar.get(Calendar.YEAR);
int mn = calendar.get(Calendar.MONTH);
int dts = calendar.get(Calendar.DATE);
String dt = dts+"/"+mn+"/"+yr;
comboBox.addItem(dt);
// check Look and Feel
background = UIManager.getColor("ComboBox.background");
foreground = UIManager.getColor("ComboBox.foreground");
selectedBackground = UIManager.getColor("ComboBox.selectionBackground");
selectedForeground = UIManager.getColor("ComboBox.selectionForeground");

initializePopup();
}


public void show() {
try {
// if setSelectedItem() was called with a valid date, adjust the calendar
calendar.setTime( dateFormat.parse( comboBox.getSelectedItem().toString() ) );
} catch (Exception e) {}
updatePopup();
popup.show(comboBox, 0, comboBox.getHeight());
}

public void hide() {
popup.setVisible(false);
}

protected JList list = new JList();
public JList getList() {
return list;
}

public MouseListener getMouseListener() {
return this;
}

public MouseMotionListener getMouseMotionListener() {
return this;
}

public KeyListener getKeyListener() {
return this;
}

public boolean isVisible() {
return popup.isVisible();
}

public void uninstallingUI() {
popup.removePopupMenuListener(this);
}


public void mousePressed( MouseEvent e ) {}
public void mouseReleased( MouseEvent e ) {}
// something else registered for MousePressed
public void mouseClicked(MouseEvent e) {
if ( !SwingUtilities.isLeftMouseButton(e) )
return;
if ( !comboBox.isEnabled() )
return;
if ( comboBox.isEditable() ) {
comboBox.getEditor().getEditorComponent().requestFocus();
} else {
comboBox.requestFocus();
}
togglePopup();
}

protected boolean mouseInside = false;
public void mouseEntered(MouseEvent e) {
mouseInside = true;
}
public void mouseExited(MouseEvent e) {
mouseInside = false;
}

// MouseMotionListener
public void mouseDragged(MouseEvent e) {}
public void mouseMoved(MouseEvent e) {}

// KeyListener
public void keyPressed(KeyEvent e) {}
public void keyTyped(KeyEvent e) {}
public void keyReleased( KeyEvent e ) {
if ( e.getKeyCode() == KeyEvent.VK_SPACE ||
e.getKeyCode() == KeyEvent.VK_ENTER ) {
togglePopup();
}
}


public void popupMenuCanceled(PopupMenuEvent e) {}
protected boolean hideNext = false;
public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
hideNext = mouseInside;
}
public void popupMenuWillBecomeVisible(PopupMenuEvent e) {}


protected void togglePopup() {
if ( isVisible() || hideNext ) {
hide();
} else {
show();
}
hideNext = false;
}


// Note *** did not use JButton because Popup closes when pressed
protected JLabel createUpdateButton(final int field, final int amount) {
final JLabel label = new JLabel();
final Border selectedBorder = new EtchedBorder();
final Border unselectedBorder = new EmptyBorder(selectedBorder.getBorderInsets(new JLabel()));
label.setBorder(unselectedBorder);
label.setForeground(foreground);
label.addMouseListener(new MouseAdapter() {
public void mouseReleased(MouseEvent e) {
calendar.add(field, amount);
updatePopup();
}
public void mouseEntered(MouseEvent e) {
label.setBorder(selectedBorder);
}
public void mouseExited(MouseEvent e) {
label.setBorder(unselectedBorder);
}
});
return label;
}


protected void initializePopup() {
JPanel header = new JPanel(); // used Box, but it wasn't Opaque
header.setLayout(new BoxLayout(header, BoxLayout.X_AXIS));
header.setBackground(background);
header.setOpaque(true);

JLabel label;
label = createUpdateButton(Calendar.YEAR, -1);
label.setText("<<");
label.setToolTipText("Previous Year");

header.add(Box.createHorizontalStrut(12));
header.add(label);
header.add(Box.createHorizontalStrut(12));

label = createUpdateButton(Calendar.MONTH, -1);
label.setText("<");
label.setToolTipText("Previous Month");
header.add(label);

monthLabel = new JLabel("", JLabel.CENTER);
monthLabel.setForeground(foreground);
header.add(Box.createHorizontalGlue());
header.add(monthLabel);
header.add(Box.createHorizontalGlue());

label = createUpdateButton(Calendar.MONTH, 1);
label.setText(">");
label.setToolTipText("Next Month");
header.add(label);

label = createUpdateButton(Calendar.YEAR, 1);
label.setText(">>");
label.setToolTipText("Next Year");

header.add(Box.createHorizontalStrut(12));
header.add(label);
header.add(Box.createHorizontalStrut(12));

popup = new JPopupMenu();
popup.setBorder(BorderFactory.createLineBorder(Color.black));
popup.setLayout(new BorderLayout());
popup.setBackground(background);
popup.addPopupMenuListener(this);
popup.add(BorderLayout.NORTH, header);
}

// update the Popup when either the month or the year of the calendar has been changed
protected void updatePopup() {
monthLabel.setText( monthFormat.format(calendar.getTime()) );
if (days != null) {
popup.remove(days);
}
days = new JPanel(new GridLayout(0, 7));
days.setBackground(background);
days.setOpaque(true);

Calendar setupCalendar = (Calendar) calendar.clone();
setupCalendar.set(Calendar.DAY_OF_WEEK, setupCalendar.getFirstDayOfWeek());
for (int i = 0; i < 7; i++) {
int dayInt = setupCalendar.get(Calendar.DAY_OF_WEEK);
JLabel label = new JLabel();
label.setHorizontalAlignment(JLabel.CENTER);
label.setForeground(foreground);
if (dayInt == Calendar.SUNDAY) {
label.setText("Sun");
} else if (dayInt == Calendar.MONDAY) {
label.setText("Mon");
} else if (dayInt == Calendar.TUESDAY) {
label.setText("Tue");
} else if (dayInt == Calendar.WEDNESDAY) {
label.setText("Wed");
} else if (dayInt == Calendar.THURSDAY) {
label.setText("Thu");
} else if (dayInt == Calendar.FRIDAY) {
label.setText("Fri");
} else if (dayInt == Calendar.SATURDAY){
label.setText("Sat");
}
days.add(label);
setupCalendar.roll(Calendar.DAY_OF_WEEK, true);
}

setupCalendar = (Calendar) calendar.clone();
setupCalendar.set(Calendar.DAY_OF_MONTH, 1);
int first = setupCalendar.get(Calendar.DAY_OF_WEEK);
for (int i = 0; i < (first - 1); i++) {
days.add(new JLabel(""));
}
for (int i = 1; i <= setupCalendar.getActualMaximum(Calendar.DAY_OF_MONTH); i++) {
final int day = i;
final JLabel label = new JLabel(String.valueOf(day));
label.setHorizontalAlignment(JLabel.CENTER);
label.setForeground(foreground);
label.addMouseListener(new MouseListener() {
public void mousePressed(MouseEvent e) {}
public void mouseClicked(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {
label.setOpaque(false);
label.setBackground(background);
label.setForeground(foreground);
calendar.set(Calendar.DAY_OF_MONTH, day);
comboBox.setSelectedItem(dateFormat.format(calendar.getTime()));
hide();
comboBox.requestFocus();
}
public void mouseEntered(MouseEvent e) {
label.setOpaque(true);
label.setBackground(selectedBackground);
label.setForeground(selectedForeground);
}
public void mouseExited(MouseEvent e) {
label.setOpaque(false);
label.setBackground(background);
label.setForeground(foreground);
}
});

days.add(label);
}

popup.add(BorderLayout.CENTER, days);
popup.pack();
}
}

public static void main(String args[])
{
JFrame f = new JFrame();
Container c = f.getContentPane();
c.setLayout(new FlowLayout());
c.add(new JLabel("Date:"));
DateComboBox dcb = new DateComboBox();
c.add(dcb);
f.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
f.setSize(200, 100);
f.show();
}

}