Handling KeyEvent (filtering KeyEvents)

Question

I am writing a code to learn how KeyEvents behaves and how to manipulate and even filtering some events, for example, to filter the normal behaviour of keeping pressed a key that fires a KeyPressed -> KeyTyped -> KeyReleased Events, like pressing the 'a' button, and keeping it pressed, this fires the sequence expressed before as long as the button is keeped pressed.
From the writing a KeyListener tutorial, (http://java.sun.com/docs/books/tutorial/uiswing/events/keylistener.html), i've begin to make some tests and changing somethings around the code, but, i am not getting too far as I want to make the 'keeping pressed' behaviour as just one event, the KeyPressed, and only when the user release the key, the KeyReleased Event should be fired.
In resume, i just want to make any keystroke to be mapped as a modifier key, such as Shift or Control, because i will need a program which only responds with a character to the user, when he releases the key and not just like the KeyTyped Event.
I am not a programmer, i am just a psychology student who wants to learn about Java programming language and try to apply it to some ideas about how to gather information about the behaviour of people when it's method of interact (virtually) is the keyboard realm.
Is there anything out there to help me on this trail of learning how to manipulate KeyEvents?
Thanks in advance, and sorry for the poor english.

Answer 1

Hi,
This is a bit of a hack but works nicely. Substitute the keyPressed, KeyReleased and keyTyped methods with the following:
    /** Handle the key typed event from the text field. */
    public void keyTyped(KeyEvent e) {
    //    displayInfo(e, "KEY TYPED: ");
    /** Handle the key pressed event from the text field. */
    public void keyPressed(KeyEvent e) {
        if(key != e.getKeyChar()) {
            displayInfo(e, "KEY PRESSED: ");
            key = e.getKeyChar();
    /** Handle the key released event from the text field. */
    public void keyReleased(KeyEvent e) {
        displayInfo(e, "KEY RELEASED: ");
        key = ' ';
    }and declare a char as a class varible like this:
// ... import statements here
public class KeyEventDemo extends JPanel
                          implements KeyListener,
                                     ActionListener {
    JTextArea displayArea;
    JTextField typingArea;
    static final String newline = "\n";
    // This is where you'll put the char.
    char key;
    public KeyEventDemo() {
        super(new BorderLayout());
        // ... the rest of the class