How can a KeyListener detect key combinations (e.g., ALT + 1 + 1)

Question

How can I let my custom KeyListener listen for combinations of ALT (or CTRL for that matter) + more than one other key?

Assume

Answer 1

ALT + 1 + 0 (or "ALT+10" as it could be described in a Help file or similar)

seems to clash with (from one of your comments):

So for example if the user wants to change data in column 11 (which would be called "10"), s/he'd press ALT + 1 + [lets go of both ALT and 1] 0.

Assuming that ALT+10 means 'Pressing ALT, pressing and releasing 1, pressing and releasing 0, releasing ALT' I propose trying this:

In keyPressed, listening for the ALT key, activate a boolean flag, isAltPressed, and create a buffer to hold key presses that occur (a string, say). In keyTyped, if isAltPressed is active, append key codes to the buffer. In keyReleased, listening for ALT again, open a conditional querying the buffer and executing actions.

    public void keyPressed (KeyEvent e){
        if (e.getKeyCode() == KeyEvent.VK_ALT){
        buffer = ""; //declared globally
        isAltPressed = true; } //declared globally
    }

    public void keyTyped (KeyEvent e){
        if (isAltPressed)
            buffer.append (e.getKeyChar());
    }

    public void keyReleased (KeyEvent e){
        if (e.getKeyCode() == KeyEvent.VK_ALT){
            isAltPressed = false;
            if (buffer.equals (4948)) //for pressing "1" and then "0"
                doAction();
            else if (buffer.equals(...))
                doOtherAction();
            ...
        }//if alt
    }