Mega Code Archive
Time panel shows the current time
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/*
* Copyright (C) 2002-2003 Colin Bell
* colbell@users.sourceforge.net
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
import java.awt.Dimension;
import java.awt.FontMetrics;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DateFormat;
import java.util.Calendar;
import javax.swing.JLabel;
import javax.swing.Timer;
import javax.swing.border.Border;
/**
* Time panel. This will show the current time.
* A timer to update the time is started when the component
* is added to its parent and stopped when removed from its parent.
*
* @author <A HREF="mailto:colbell@users.sourceforge.net">Colin Bell</A>
*/
public class TimePanel extends JLabel implements ActionListener
{
/** Timer that updates time. */
private Timer _timer;
/** Used to format the displayed date. */
private DateFormat _fmt = DateFormat.getTimeInstance(DateFormat.LONG);
private Dimension _prefSize;
private Calendar _calendar = Calendar.getInstance();
/**
* Default ctor.
*/
public TimePanel()
{
super("", JLabel.CENTER);
}
/**
* Add component to its parent. Start the timer for auto-update.
*/
public void addNotify()
{
super.addNotify();
_timer = new Timer(1000, this);
_timer.start();
}
/**
* Remove component from its parent. Stop the timer.
*/
public void removeNotify()
{
super.removeNotify();
if (_timer != null)
{
_timer.stop();
_timer = null;
}
}
/**
* Update component with the current time.
*
* @param evt The current event.
*/
public void actionPerformed(ActionEvent evt)
{
_calendar.setTimeInMillis(System.currentTimeMillis());
setText(_fmt.format(_calendar.getTime()));
}
/**
* Return the preferred size of this component.
*
* @return the preferred size of this component.
*/
public Dimension getPreferredSize()
{
if(null == _prefSize)
{
// This was originaly done every time.
// and the count of instantiated objects was amazing
_prefSize = new Dimension();
_prefSize.height = 20;
FontMetrics fm = getFontMetrics(getFont());
Calendar cal = Calendar.getInstance();
cal.set(Calendar.HOUR_OF_DAY, 23);
cal.set(Calendar.MINUTE, 59);
cal.set(Calendar.SECOND, 59);
_prefSize.width = fm.stringWidth(_fmt.format(cal.getTime()));
Border border = getBorder();
if (border != null)
{
Insets ins = border.getBorderInsets(this);
if (ins != null)
{
_prefSize.width += (ins.left + ins.right);
}
}
Insets ins = getInsets();
if (ins != null)
{
_prefSize.width += (ins.left + ins.right) + 20;
}
}
return _prefSize;
}
}
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