Name: boT120536 Date: 05/20/2001


java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0)
Java HotSpot(TM) Client VM (build 1.3.0, mixed mode)

Compile the single source file, attached.
Execute it.

A JFrame will display (300x300) with a sample Menubar.
It waits for key events to occur inside of it.

NOTE 2 RELATED(?) BUGS are reported:

  Bug #1
------
Select the JFrame and press the MINUS key
located on the keyboard.

The program will display messages to stdout
describing the key event.


  Bug #2
------
Select the menu bar; notice a single menu item
with an accelerator key set for the MINUS key.

The accelerator is set to "Ctrl+MINUS".

We expected it to be set to "Ctrl+-" and have
found no way to set the "-" character as the
accelerator string. The effort to do so resulted
in finding the Bug #1 listed above.

Notice that for KEY TYPED, key code is "Unknown"
for the MINUS key.


Source Code:
------------

// ------------------------------------------------------------
// KeyboardListener.java --- A generic KeyListener object.
// ------------------------------------------------------------
//
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;


/**
 * Implements and provides a default implementation for a KeyListener
interface.
 */
public class KeyboardListener implements KeyListener
{
  /**
   * Null constructor.
   */
  public KeyboardListener()
  {
  }

  //
  // ----------------- KeyListener event handlers ---------------
  // These handlers are the default implementation. Subclasses should
  // override these methods if interested/necessary.
  /** Handle a component-defined keyboard event (keyPressed) that has occured.
   * @param KeyEvent the keystroke event data generated by the component object
   * as a result of the user pressing a key within the component object.
   */
  public void keyPressed(KeyEvent ke)
  {
    displayInfo(ke, "KEY PRESSED: ");
  }

  /** Handle a component-defined keyboard event (keyReleased) that has occured.
   * @param KeyEvent the keystroke event data generated by the component object
   * as a result of the user releasing a pressed key within the component
   * object.
   * @param KeyEvent the key event generated by the user w/ a key press.
   */
  public void keyReleased(KeyEvent ke)
  {
    displayInfo(ke, "KEY RELEASED: ");
    System.out.println("\n");
  }


  /** Handle a component-defined keyboard event (keyTyped) that has occured.
   * @param KeyEvent the keystroke event data generated by the component object
   * as a result of the user typing a key (press and then release) within the
   * component object.
   * @param KeyEvent the key event generated by the user w/ a key press.
   */
  public void keyTyped(KeyEvent ke)
  {
    displayInfo(ke, "KEY TYPED: ");
  }


  /**
   * Private helper method for debugging or verbose output.
   * @param String a text desdcription of the event.
   * @param AWTEvent a generic event.
   */
  private void printMessage(String eventDescription, AWTEvent e)
  {
    System.out.println("\n" + eventDescription + e.toString());
  }

  /**
   * Display some useful information about the KeyEvent.
   * @param KeyEvent the key event generated by the user w/ a key press.
   * @param String an information string to print to stdout.
   */
  protected void displayInfo(KeyEvent e, String s)
  {
    String charString, keyCodeString, modString, tmpString;
    String newline = "\n";

    char c = e.getKeyChar();
    int keyCode = e.getKeyCode();
    int modifiers = e.getModifiers();

    if (Character.isISOControl(c))
    {
      charString = "key character = " + "(an unprintable control character)";
    }
    else
    {
      charString = "key character = '"
                   + c + "'";
    }

    keyCodeString = "key code = " + keyCode
                    + " ("
                    + KeyEvent.getKeyText(keyCode)
                    + ")";

    modString = "modifiers = " + modifiers;
    tmpString = KeyEvent.getKeyModifiersText(modifiers);
    if (tmpString.length() > 0)
    {
      modString += " (" + tmpString + ")";
    }
    else
    {
      modString += " (no modifiers)";
    }

    System.out.println(s + newline
                       + " " + charString + newline
                       + " " + keyCodeString + newline
                       + " " + modString + newline);
  }

  //
  // -----------------
  // Main Test Driver
  // -----------------
  //
  //
   public static void main(String[] args)
   {
    JFrame frame = new JFrame("Testing key listener");

    JMenuBar menuBar = new JMenuBar();
    JMenu testMenu = new JMenu("Test");
    JMenuItem menuItem = new JMenuItem("test item");

    // Set menu item attributes
    menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_MINUS,
ActionEvent.CTRL_MASK));

    // Finish up and display
    testMenu.add(menuItem);
    menuBar.add(testMenu);
    frame.getRootPane().setMenuBar(menuBar);

    frame.addKeyListener(new KeyboardListener());
    frame.setSize(300,300);
    frame.setVisible(true);
  }
}
(Review ID: 124695)
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