Opening a new window when double clicking on a JTable row

Add a MouseListener to your JTable.

Main.java:

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
 
public class Main extends JFrame 
{
   public Main() {
      super("Table example, Wines from Bordeaux");
 
      final Object[][] tabledata = {
            { "Chateau Meyney, St. Estephe", 	   new Integer(1994), "$18.75"},
            { "Chateau Montrose, St. Estephe", 	   new Integer(1975), "$54.25" },
            { "Chateau Gloria, St. Julien", 	   new Integer(1993), "$22.99" },
            { "Chateau Beychevelle, St. Julien",   new Integer(1970), "$61.63" },
            { "Chateau La Tour de Mons, Margeaux", new Integer(1975), "$57.03" },
            { "Chateau Brane-Cantenac, Margeaux",  new Integer(1978), "$49.92" },
      };
 
      String columnheaders[] = { "Wine", "Vintage", "Price" };
 
      JTable table = new JTable(tabledata, columnheaders) {
         public boolean editCellAt(int row, int column, java.util.EventObject e) {
            return false;
         }
      };
 
      table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
      table.setPreferredScrollableViewportSize(new Dimension(500, 70));
      JScrollPane scrollPane = new JScrollPane(table);
      getContentPane().add(scrollPane);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
 
      pack();
 
      table.addMouseListener(new MouseAdapter() {
         public void mouseClicked(MouseEvent e) {
            if (e.getClickCount() == 2) {
               JTable target = (JTable) e.getSource();
               int row = target.getSelectedRow();
               StringBuffer sb = new StringBuffer();
               String lineSeparator = System.getProperty("line.separator");
               sb.append(tabledata[row][0] + lineSeparator);
               sb.append(tabledata[row][1] + lineSeparator);
               sb.append(tabledata[row][2] + lineSeparator);
               TextFrame textFrame = new TextFrame(sb.toString());
               textFrame.setVisible(true);
            }
         }
      });
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.show();
   }
}
 
class TextFrame extends JFrame
{
   public TextFrame(String content) {
      super("TextFrame");
 
      JTextArea ta = new JTextArea();
      ta.setText(content);
      getContentPane().add(ta);
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            dispose();
         }
      });
      
      setSize(200, 100);
   }
}

Incorporating speech in a Swing application

1) First you need to download a speech engine. For example, you can download for free the Microsoft’s Speech SDK here. (Beware: version 5.1 is 68MB). Use the tools available to make sure the SDK is properly installed and trained to your voice.

2) Then get an implementation of Sun’s Java Speech API (JSAPI). The one I used in this example is from the CloudGarden. Follow the instructions on this page to find out how to install: copy the files jsapi.dll and jsapi.jar to JRE_HOME/lib/ext and adjust your classpath so that it includes jsapi.jar, necessary to compile following sample program.

3) This sample program was written by looking at the Cloud Garden examples. I dictated the following text to the app: “Last night, after a productive day of work, I joined my girlfriend in bed and quoted a very famous poet, who’s name escapes me. I said: ‘I feel great sexual desire for you right now.’. She said she’s not into poetry.”. The result (see window) was better than I expected.

Main.java:

import javax.speech.recognition.*;
import javax.speech.synthesis.*;
import javax.speech.*;
 
import javax.swing.text.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
 
public class Main extends JFrame
{ 
   TextComponentSpeechEnabler tcse;
 
   public Main() {
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            tcse.deallocate();
            System.exit(1);
         }
      });
 
      getContentPane().setLayout(new BorderLayout(10, 10));
      JTextArea textArea = new JTextArea();
      textArea.setLineWrap(true);
 
      try {
         tcse = new TextComponentSpeechEnabler(textArea);
         getContentPane().add(BorderLayout.CENTER, tcse.getPanel());
      }
      catch(Exception e) {
         e.printStackTrace();
      }
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(500, 500);
      main.setVisible(true);
   }
}
 
class TextComponentSpeechEnabler
{
   static Recognizer recognizer;
 
   JPanel         textComponentPanel;
   JTextComponent textComponent;
   JTextField     speakerName;
   JTextArea      statusArea;
 
   public TextComponentSpeechEnabler(JTextComponent textComponent) throws Exception {
      this.textComponent = textComponent;
      
      createPanel();
      initializeRecognizer();
   }
  
   public void initializeRecognizer() throws Exception {
      recognizer = Central.createRecognizer(null);
      recognizer.addResultListener(new MyResultListener());
      recognizer.allocate();
      recognizer.waitEngineState(Recognizer.ALLOCATED);
 
      SpeakerManager speakerManager = recognizer.getSpeakerManager();
      SpeakerProfile[] speakers = speakerManager.listKnownSpeakers();
      for (int i=0; i<speakers.length; i++) {
         addStatusText("Found profile of " + speakers[i].getName());
      }
 
      addStatusText("Current profile is " +
                                   speakerManager.getCurrentSpeaker().getName());
      speakerName.setText(speakerManager.getCurrentSpeaker().getName());
      speakerManager.setCurrentSpeaker(speakers[0]);
 
      DictationGrammar dictation = recognizer.getDictationGrammar("dictation");
      dictation.setEnabled(true);
 
      recognizer.commitChanges();
 
      recognizer.requestFocus();
      recognizer.resume(); 
   }
 
   public void deallocate() {
      System.out.println("deallocated!");
      try {
         recognizer.deallocate();
      }
      catch(Exception e) {
         e.printStackTrace();
      }
   }
 
   private void createPanel() {
      textComponentPanel = new JPanel(new BorderLayout(10, 10));
      JPanel northPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
      northPanel.add(new JLabel("Speaker name:  "));
      speakerName = new JTextField(25);
      northPanel.add(speakerName);
      textComponentPanel.add(BorderLayout.NORTH, northPanel);
      textComponentPanel.add(BorderLayout.CENTER, new JScrollPane(textComponent));
 
      statusArea = new JTextArea(10, 50);
      textComponentPanel.add(BorderLayout.SOUTH, new JScrollPane(statusArea));   
   }
  
   public JPanel getPanel() {
      return textComponentPanel;
   }
 
   public void addStatusText(final String s) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            statusArea.append(s + "n");
            statusArea.setCaretPosition(statusArea.getDocument().getLength());
         }
      });
   }
 
   public void addText(final String s) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            textComponent.setText(textComponent.getText() + s);
            textComponent.setCaretPosition(textComponent.getDocument().getLength());
         }
      });
   }
  
   class MyResultListener extends ResultAdapter {
      public void resultRejected(ResultEvent e) {
      }
 
      public void resultCreated(ResultEvent e) {
      }
 
      public void resultUpdated(ResultEvent e) {
      }
 
      public void resultAccepted(ResultEvent e) {
         FinalResult finalResult = (FinalResult)(e.getSource());
         ResultToken tokens[] = null;
         tokens = finalResult.getBestTokens();
 
         StringBuffer sb = new StringBuffer();
         for (int i=0; i<tokens.length; i++) {
            sb.append(tokens[i].getSpokenText() + " ");  
         }
         addText(sb.toString());
         addStatusText("" + finalResult);
      }
   }
}

Feel free to mail me any improvements!

Adding a JMenuBar to the two components of a JSplitPane

Main.java:

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
 
public class Main extends JFrame
{
   JSplitPane splitPane;
  
   public Main() {
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
 
      JPanel firstPanel = createPanel();
      JPanel secondPanel = createPanel();
      splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, firstPanel, secondPanel);
 
      createMainMenuBar();
 
      getContentPane().add(splitPane);
      setSize(300, 300);
      setVisible(true);
 
      splitPane.setDividerLocation(0.5); 
   }
 
   public void createMainMenuBar() {
      JMenuBar mainBar = new JMenuBar();
      JMenu menu = new JMenu(&amp;quot;JSplitPane&amp;quot;);
      JMenuItem item1 = new JMenuItem(&amp;quot;HORIZONTAL_SPLIT&amp;quot;);
      JMenuItem item2 = new JMenuItem(&amp;quot;VERTICAL_SPLIT&amp;quot;);
      menu.add(item1);
      menu.add(item2);
      mainBar.add(menu);
      setJMenuBar(mainBar);
 
      item1.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            splitPane.setOrientation(JSplitPane.HORIZONTAL_SPLIT);
         }
      });
 
      item2.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            splitPane.setOrientation(JSplitPane.VERTICAL_SPLIT);
         }
      });
   }
 
   public JPanel createPanel() {
      JPanel panel = new JPanel();
      panel.setLayout(new BorderLayout());
      JMenuBar menuBar = new JMenuBar();
      for (int i=0; i&amp;lt;3; i++) {
         JMenu menu = new JMenu(&amp;quot;JMenu &amp;quot; + (i+1));
         for (int j=0; j&amp;lt;3; j++) {
            JMenuItem item = new JMenuItem(&amp;quot;JMenuItem &amp;quot; + (j+1));
            menu.add(item);
         }
         menuBar.add(menu);
      }
      panel.add(BorderLayout.NORTH, menuBar);
 
      return panel;
   }
 
   public static void main(String []args) {
      Main main = new Main();
   }
}

Catching events while an image is being read using ImageIO

Add an IIOReadProgressListener to your reader.

   IIOReadProgressListener listener = new MyReadProgressListener();
   reader.addIIOReadProgressListener(listener);

It’ll throw events while the reading process is going on. The following example shows a JProgressBar while reading the image fruit.png, to be used as background.

Main.java:

import javax.imageio.metadata.*; 
import javax.imageio.stream.*;
import javax.imageio.event.*;
import javax.imageio.*;
 
import javax.swing.event.*;
import java.awt.image.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*; 
import java.io.*;
  
public class Main extends JFrame
{
   JProgressBar progressBar;
   BufferedImage background = null;
  
   public Main() {
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(1);
         }
      });
 
      progressBar = new JProgressBar(0, 100);
 
      getContentPane().setLayout(new BorderLayout());
      getContentPane().add(BorderLayout.NORTH, progressBar);
    }
 
   public void loadBackgroundImage(String filename) throws Exception {
      Iterator readers = ImageIO.getImageReadersByFormatName("png");
      ImageReader reader = (ImageReader) readers.next();
 
      IIOReadProgressListener listener = new MyReadProgressListener();
      reader.addIIOReadProgressListener(listener);
 
      ImageInputStream iis = ImageIO.createImageInputStream(new File(filename));
      reader.setInput(iis, true);
      background = reader.read(0);
   }
 
   public static void main(String []args) throws Exception {
      Main main = new Main();
      main.setSize(400, 150);
      main.setVisible(true);
  
      main.loadBackgroundImage("fruit.png");
   }
 
   public void paint(Graphics g) {
      System.out.println(background);
      if (background != null) {
         g.drawImage(background, 0, 0, getWidth(), getHeight(), this);
      }
   }
 
   class MyReadProgressListener implements IIOReadProgressListener {
 
	public MyReadProgressListener() {}
 
        public void imageProgress(ImageReader source, final float percentageDone) {
           System.out.println("imageProgress: " + percentageDone);
 
           SwingUtilities.invokeLater(new Runnable() {
              public void run() {
                 progressBar.setValue((int) percentageDone);
              }
           });   
        }
 
        public void imageComplete(ImageReader source) {
           SwingUtilities.invokeLater(new Runnable() {
              public void run() {
                 try {
                    // wait for a bit until bufferedimage is assigned by reader
                    Thread.sleep(50);
                 }
                 catch(InterruptedException e) { }
                 repaint();
              }
           });              
        }
 
        public void imageStarted(ImageReader source, int imageIndex)  { }
        public void readAborted(ImageReader source)                   { }
        public void sequenceComplete(ImageReader source)              { }
        public void sequenceStarted(ImageReader source, int minIndex) { }
        public void thumbnailComplete(ImageReader source)             { }
        public void thumbnailProgress(ImageReader source, float percentageDone) { }
        public void thumbnailStarted(ImageReader source, int imageIndex, int thumbnailIndex) { }
   }
}

Adding blank space between elements of a JToolBar

Set an empty border on your JButtons that you add to your JToolBar!

Main.java:

import javax.swing.border.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
  
public class Main extends JFrame {
   public Main() {
      super("JToolBar example");
 
      final JTextArea textArea = new JTextArea(5, 30);
      JToolBar toolBar = new JToolBar();
 
      JButton gifButton = new JButton(new ImageIcon("gifIcon.gif"));
      JButton jpgButton = new JButton(new ImageIcon("jpgIcon.gif"));
      JButton tiffButton = new JButton(new ImageIcon("tiffIcon.gif"));
 
      gifButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            textArea.append("gifButton clicked!n");
         }
      });
 
      jpgButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            textArea.append("jpgButton clicked!n");
         }
      });
        
      tiffButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            textArea.append("tiffButton clicked!n");
         }
      });
 
      gifButton.setBorder(new EmptyBorder(new Insets(10,10,10,1)));
      jpgButton.setBorder(new EmptyBorder(new Insets(10,10,10,10)));
      tiffButton.setBorder(new EmptyBorder(new Insets(10,10,10,10)));
 
      toolBar.add(gifButton);
      toolBar.add(jpgButton);
      toolBar.add(tiffButton);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            System.exit(0);
         }
      });
 
      getContentPane().setLayout(new BorderLayout());
      getContentPane().add(BorderLayout.NORTH, toolBar);
      getContentPane().add(BorderLayout.CENTER, new JScrollPane(textArea));
   }
 
   public static void main(String[] args) {
      Main main = new Main();
      main.setSize(300, 300);
      main.setVisible(true);
   }
}

images used in this app:


Setting the background image for a JInternalFrame

Main.java:

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.net.*;
 
public class Main extends JFrame {
   JDesktopPane desktop;
   int nframes = 0;
 
   public Main() {
      getContentPane().setLayout(new BorderLayout());
      desktop = new JDesktopPane(); 
      createInternalFrame();
      getContentPane().add(BorderLayout.CENTER, desktop);
      setJMenuBar(createMenuBar());
  
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   
      setTitle("Transparent JInternalFrame Demonstration");
      setSize(new Dimension(400, 400));
   }
 
   protected JMenuBar createMenuBar() {
      JMenuBar menuBar = new JMenuBar();
 
      JMenu menu = new JMenu("JDesktopPane");
      JMenuItem menuItem1 = new JMenuItem("Create new JInternalFrame");
      menuItem1.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            createInternalFrame();
         }
      });
      menu.add(menuItem1);
      menuBar.add(menu);
 
      return menuBar;
   }
 
   protected void createInternalFrame() {
      JInternalFrame frame = new JInternalFrame("InternalFrame", 
         true,    // resizable
         true,    // closable
         true,    // maximizable
         true);   // iconifiable
      frame.setVisible(true); 
      desktop.add(frame);
      frame.setSize(200, 200);
      frame.setLocation(30*nframes, 30*nframes);
      nframes++;
      frame.setContentPane(new ImageBackgroundPanel(
                             new ImageIcon("mong.jpg")));
 
      frame.getContentPane().add(new JLabel("Your name"));
      frame.getContentPane().add(new JTextField(10));
 
      try {
         frame.setSelected(true);
      } catch (java.beans.PropertyVetoException e) {}
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.show();
   }
}
 
class ImageBackgroundPanel extends JPanel
{
   private ImageIcon bgImage;
 
   public ImageBackgroundPanel(ImageIcon bgImage) {
      this.bgImage = bgImage;
   }
 
   public void paintComponent(Graphics g) {    
      Dimension d = getSize();      
      g.drawImage(bgImage.getImage(), 0, 0, (int)d.getWidth(), (int)d.getHeight() , this);          
   }
}

Defining the size of a JComboBox

If you want to change the size of the JComboBox component itself, use:

   combobox.setPreferredSize(new Dimension(x, y));

If you want to have control over the popupwidth and popupheight, extend JComboBox and add the necessary functionality to a custom ComboBoxUI:
Main.java:

import javax.swing.plaf.metal.*;
import javax.swing.plaf.basic.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
    
public class Main extends JFrame
{ 
   public Main() {
      getContentPane().setLayout(new FlowLayout());
      
      Vector v = new Vector();
      for (int i=0; i<20; i++)
         v.addElement("ComboBox Item #" + i);
      SizedJComboBox combobox = new SizedJComboBox(v);
 
      combobox.setPopupWidth(190);
      combobox.setPopupHeight(30);
 
      getContentPane().add(combobox);
  
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(1);
         }
      });      
   
      setSize(new Dimension(200, 200));
   } 
 
   public static void main(String[] args) throws Exception {
      Main main = new Main();
      main.setVisible(true);
   }
}
 
class SizedJComboBox extends JComboBox {
   protected int popupWidth;
   protected int popupHeight;
 
   public SizedJComboBox(ComboBoxModel aModel) {
      super(aModel);
      setUI(new SizedComboBoxUI());
   }
 
   public SizedJComboBox(final Object[] items) { 
      super(items); 
      setUI(new SizedComboBoxUI());
   } 
 
   public SizedJComboBox(Vector items) { 
      super(items); 
      setUI(new SizedComboBoxUI()); 
   } 
 
   public void setPopupWidth(int width) { 
      popupWidth = width; 
   }
 
   public void setPopupHeight(int height) {
      popupHeight = height;
   } 
 
   public Dimension getPopupSize() { 
      Dimension size = getSize(); 
      if (popupWidth < 1) popupWidth = size.width; 
      return new Dimension(popupWidth, popupHeight); 
   } 
}
 
class SizedComboBoxUI extends MetalComboBoxUI {
   protected ComboPopup createPopup() { 
      BasicComboPopup popup = new BasicComboPopup(comboBox) { 
         public void show() { 
            Dimension popupSize = ((SizedJComboBox) comboBox).getPopupSize(); 
            popupSize.setSize(popupSize.width, popupSize.height < 1 ? getPopupHeightForRowCount(comboBox.getMaximumRowCount()) : popupSize.height); 
            Rectangle popupBounds = computePopupBounds( 0, 
                  comboBox.getBounds().height, popupSize.width, popupSize.height); 
            scroller.setMaximumSize(popupBounds.getSize()); 
            scroller.setPreferredSize(popupBounds.getSize()); 
            scroller.setMinimumSize(popupBounds.getSize()); 
            list.invalidate(); 
            int selectedIndex = comboBox.getSelectedIndex(); 
            if (selectedIndex == -1) { 
               list.clearSelection(); 
            } else { 
               list.setSelectedIndex( selectedIndex ); 
            } 
            list.ensureIndexIsVisible( list.getSelectedIndex() ); 
            setLightWeightPopupEnabled(comboBox.isLightWeightPopupEnabled()); 
 
            show(comboBox, popupBounds.x, popupBounds.y); 
         } 
      }; 
 
      popup.getAccessibleContext().setAccessibleParent(comboBox); 
      return popup; 
   } 
} 

Detecting a double-click on an element in a JList

For detecting double-clicking, add a MouseListener and catch the MouseEvents where clickCount is equal to 2.

Here’s an example:

import javax.swing.event.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
import java.awt.*;
  
public class Main extends JFrame {
 
   public Main() {
      getContentPane().setLayout(new FlowLayout());
 
      Vector v = new Vector();
      for (int i=0; i<50; i++) {
         v.addElement("Item #" + i);
      }
      getContentPane().add(new JLabel("Double-clicked on: "));
      final JTextField dblTextField = new JTextField(15);
      getContentPane().add(dblTextField);
      final JList list = new JList(v);
 
      // catch double-click events
      list.addMouseListener(new MouseAdapter() {
         public void mouseClicked(MouseEvent me) {
            if (me.getClickCount() == 2) {
               dblTextField.setText(""+list.getSelectedValue()); 
            }
         }
      });
 
      getContentPane().add(new JScrollPane(list));    
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent event) {
            System.exit(0);   
         }      
      });
 
      setSize(200, 300);
   }
   
   public static void main(String[] args) {
      (new Main()).show();
   }
}

Changing the font of a JMenuItem

You can either embed HTML in the JMenuItem’s text, or you can call the method setFont.

Main.java:

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
   
public class Main extends JFrame {
   public Main() {
      getContentPane().setLayout(new FlowLayout());
 
      JMenuBar menuBar = new JMenuBar();
      JMenu menu = new JMenu("Sex");
      JMenuItem menuItem1 = new JMenuItem("<html><font size=-1>male</font></html>");
      JMenuItem menuItem2 = new JMenuItem("<html><font size=+1>female</font></html>");
      JMenuItem menuItem3 = new JMenuItem("androgyne");
      menuItem3.setFont(new Font("Monospaced", Font.ITALIC, 36));
 
      // add the MenuItems to the Menu 
      menu.add(menuItem1);
      menu.add(menuItem2);
      menu.add(menuItem3);
 
      menuBar.add(menu);
 
      this.setJMenuBar(menuBar); 
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent event) {
            System.exit(0);   
         }      
      });
 
      setSize(400, 400);
   }
 
   public static void main(String[] args) {
      (new Main()).show();
   }
}

Limiting the length of text entered in a JTextField

Create a custom component that extends from JTextField and allow the user to specify a maximum length. The implementation is simple: capture the insertString method and execute super.insertString when the condition (current length < = maximumlength) is met.

Main.java:

import javax.swing.text.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;
import java.awt.*;
   
public class Main extends JFrame {
   public Main() {
      getContentPane().setLayout(new FlowLayout());
 
      getContentPane().add(new LimitedTextField("Try typing more", 15, 15));
      getContentPane().add(new LimitedTextField(10, 3));
  
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent event) {
            System.exit(0);   
         }      
      });
 
      setSize(300, 300);
   }
 
   public static void main(String[] args) {
      (new Main()).show();
   }
}
 
class LimitedTextField extends JTextField
{
   private int maxCols = 0;
 
   public LimitedTextField(int maxCols) {
      super();
      this.maxCols = maxCols;
   }
 
   public LimitedTextField(int cols, int maxCols) {
      super(cols);
      this.maxCols = maxCols;
   }
  
   public LimitedTextField(String text, int maxCols) {
      super();
      this.maxCols = maxCols;
      setText(text);
   } 
 
   public LimitedTextField(String text, int cols, int maxCols) {
      super(cols);
      this.maxCols = maxCols;
      setText(text);
   }
 
   protected Document createDefaultModel() {
      return new LimitedDocument();
   }
  
   protected class LimitedDocument extends PlainDocument {
      public void insertString(int offset, String str, AttributeSet as) 
            throws BadLocationException  {
         if (str == null || getLength() + str.length() <= maxCols) {
            super.insertString(offset, str, as);
         }
         else {
            int remainder = maxCols – getLength();
            if (remainder > 0) {
               super.insertString(offset, str.substring(0, remainder), as);
            }
         }
      }
   }
}