ComboBoxDemo2.java

/*
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package javademo.swing.ComboBox.ComboBoxDemo2;

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

/* ComboBoxDemo2.java requires no other files. */
@SuppressWarnings("serial")
public class ComboBoxDemo2 extends JPanel implements ActionListener
{
    static JFrame frame;
    
    JLabel result;
    
    String currentPattern;
    
    public ComboBoxDemo2()
    {
        setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
        String[] patternExamples = { "dd MMMMM yyyy", "dd.MM.yy", "MM/dd/yy", "yyyy.MM.dd G 'at' hh:mm:ss z",
                "EEE, MMM d, ''yy", "h:mm a", "H:mm:ss:SSS", "K:mm a,z", "yyyy.MMMMM.dd GGG hh:mm aaa" };
        
        currentPattern = patternExamples[0];
        
        // Set up the UI for selecting a pattern.
        JLabel patternLabel1 = new JLabel("Enter the pattern string or");
        JLabel patternLabel2 = new JLabel("select one from the list:");
        
        JComboBox patternList = new JComboBox(patternExamples);
        patternList.setEditable(true);
        patternList.addActionListener(this);
        
        // Create the UI for displaying result.
        JLabel resultLabel = new JLabel("Current Date/Time", JLabel.LEADING); // == LEFT
        result = new JLabel(" ");
        result.setForeground(Color.black);
        result.setBorder(BorderFactory.createCompoundBorder(BorderFactory.createLineBorder(Color.black),
                BorderFactory.createEmptyBorder(5, 5, 5, 5)));
        
        // Lay out everything.
        JPanel patternPanel = new JPanel();
        patternPanel.setLayout(new BoxLayout(patternPanel, BoxLayout.PAGE_AXIS));
        patternPanel.add(patternLabel1);
        patternPanel.add(patternLabel2);
        patternList.setAlignmentX(Component.LEFT_ALIGNMENT);
        patternPanel.add(patternList);
        
        JPanel resultPanel = new JPanel(new GridLayout(0, 1));
        resultPanel.add(resultLabel);
        resultPanel.add(result);
        
        patternPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
        resultPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
        
        add(patternPanel);
        add(Box.createRigidArea(new Dimension(0, 10)));
        add(resultPanel);
        
        setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        
        reformat();
    } // constructor
    
    public void actionPerformed(ActionEvent e)
    {
        JComboBox cb = (JComboBox)e.getSource();
        String newSelection = (String)cb.getSelectedItem();
        currentPattern = newSelection;
        reformat();
    }
    
    /** Formats and displays today's date. */
    public void reformat()
    {
        Date today = new Date();
        SimpleDateFormat formatter = new SimpleDateFormat(currentPattern);
        try
        {
            String dateString = formatter.format(today);
            result.setForeground(Color.black);
            result.setText(dateString);
        }
        catch (IllegalArgumentException iae)
        {
            result.setForeground(Color.red);
            result.setText("Error: " + iae.getMessage());
        }
    }
    
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI()
    {
        // Create and set up the window.
        JFrame frame = new JFrame("ComboBoxDemo2");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        // Create and set up the content pane.
        JComponent newContentPane = new ComboBoxDemo2();
        newContentPane.setOpaque(true); // content panes must be opaque
        frame.setContentPane(newContentPane);
        
        // Display the window.
        frame.pack();
        frame.setVisible(true);
    }
    
    public static void main(String[] args)
    {
        // Schedule a job for the event-dispatching thread:
        // creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowGUI();
            }
        });
    }
}