Re: Best way to force a JComponent to repaint itself

From:
Lasse Reichstein Nielsen <lrn@hotpop.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 17 Aug 2008 10:59:59 +0200
Message-ID:
<d4k8aueo.fsf@hotpop.com>
zerg <zerg@zerg.org> writes:

Joshua Cranmer wrote:

You are approaching the search with a detailed knowledge of Swing
internals and design decisions. You are not approaching it from the
perspective of a user of Swing that is more concerned with doing
useful stuff with it than with knowing its in-depth implementation,
history, and so forth.


(Joshua had nothing worthwhile to say in response to this.)

It is unfortunate that it relies on Component to provide some of
its interface instead of overriding those methods (even with just a
call to super!) still relevant to Swing JComponents so that they
appear in the main listing of JComponent methods.


(Joshua had nothing worthwhile to say in response to this.)

I don't suppose you read the part of my earlier post where I mentioned
that inheritance of B from A can mean one or both of TWO things?

* B is a kind of A
* B has reused code from A

Since a Swing component does not seem to me to really be a kind of AWT
component (would a JButton work properly in an AWT Frame? On an old,
AWT-only Java deployment?)


In an AWT Frame? Yes. It IS A button in the AWT sense.
You could easily have tested this yourself. Example:
---
public class AwtSwingTest implements ActionListener {
    public static void main(String[] args) {
        Frame frame = new Frame();
        //Button button = new Button("Click me");
        JButton button = new JButton("Click me");
        button.addActionListener(new AwtSwingTest());
        frame.add(button);
        frame.setSize(100, 100);
        frame.setVisible(true);
    }
    public void actionPerformed(ActionEvent e) {
        System.out.println("Button clicked");
        System.exit(0);
    }
}
---

Would it work in an AWT-only setting? Obviously not, the class wouldn't
be there.

The Swing components are built on top of the AWT system, using IS-A
inheritance to extend the capabilities of the corresponding AWT
components. The entire JAVA system, with both AWT and Swing, is a
consistent system where Swing components naturally inherit from
AWT components. This is the system you are using, and in that, with
the traditional JavaDoc style, the documentation page of a Swing class
only explain the changes from its super-class.

it seems questionable to expect me to look there.


Well, know you know.

Particularly when it means looking in another package entirely,
and at almost the opposite end of the alphabetic listing of packages
to boot.


A superclass is a superclass. What package it is in is not important.

All of which ignores the fact that I simply looked in the most obvious
place, the alphabetic listing of methods with detailed descriptions,
as seemed reasonable. None of the information you're discussing is in
that particular place to lead me on anywhere else in turn.


True. The way JavaDoc is structured, one needs to know to look at
superclasses manually.

[about Roedy]

Really? He basically posted "The answers are here: http://etc etc etc"
and it was quite clearly his own web site.


True. His way of working appears to be to see a question, and if he
thinks the answer is generally applicable and/or the question is likely
to be asked again, then he writes up the answer on his web page and
gives a link, instead of writing the answer in a message.

I have missed nothing.
I have not made any mistakes.


Sorry Paul, I hadn't recognized your twisted writing style before.
Won't bother you again.
/L
--
Lasse Reichstein Nielsen
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