Re: subclass JPasswordField

From:
Mike <who@cares.com>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 02 Jul 2009 12:11:40 +1200
Message-ID:
<4a4bff2c$1@news.orcon.net.nz>
markspace wrote:

Mike wrote:

Just pseudo code is enough, as long as I know the basic things to look
for (like how to add a document change listener to the PlainDocument
inside the JPasswordField & how to set the timer and all).


Well, my problem with your original code is it didn't do anything at
all. Some of this stuff is pretty basic. Typing "java <interface>
tutorial" into Google almost always brings up several code examples,
including the tutorials from Sun.

Let's see: Google "java document change listener". First link:

<http://java.sun.com/docs/books/tutorial/uiswing/events/documentlistener.html>

This example actually uses a JTextField, so bonus there because it shows
you how to set the change listener on a text field.

Google "java timer tutorial". First link:

<http://java.sun.com/docs/books/tutorial/uiswing/misc/timer.html>

I think you should at least be able to create those two classes and do a
little something with them, even if you're not sure how to finish the job.


Ok, so my main question now is: How to I get to the JPasswordField that
the DocumentListener is attached to? How do I reference it?

Here's the code so far:

class TimedPasswordListener implements DocumentListener, ActionListener {
    Timer timer;
    char echoChar;

    public void insertUpdate(DocumentEvent e) {
        showText(e, 3);
    }

    public void removeUpdate(DocumentEvent e) {
        showText(e, 3);
    }

    public void changedUpdate(DocumentEvent e) {
        // Plain text components do not fire these events
    }

    public void showText(DocumentEvent e, int timeOut) {
        Document doc = (Document) e.getDocument();
        // How do I set the echo char of the JPasswordField
        // to '0' here, and how do I restore it again after
        // timeOut seconds?
        // echoChar = <JPasswordField>.getEchoChar();
        // <JPasswordField>.setEchoChar(0);
        timer = new Timer(timeOut * 1000, this);
        timer.setRepeats(false);
        timer.start();
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        Document doc = (Document) e.getSource();
        // How do I restore the echo char of the JPasswordField?
        // <JPasswordField>.setEchoChar(echoChar);
    }
}

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