How to list/access swing components?

Question

hi all,
Can anyone give me a clue, how can I access or simply list swing components I have on a frame, long after I created them. E.g. I'd like to change their setEnabled() attribute at a later time, not at creation time, but I don't know how to access them.
Does Swing/AWT/JFC provides a component hierarchy? can someone share some code on this issue?
Thanks for any help.
Thomas

Answer 1

I guess, you are saying the use of getComponent(int n)?
Since I'm a beginner in Swing see my short code below:
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JTextArea;
public class EasyFrame {
    public EasyFrame() {
        super();
        startHere();
    public void startHere() {
        JFrame frame = new JFrame("SwingApplication");
        JButton button = new JButton("click here");
        JTextArea area = new JTextArea();
        frame.setSize(300, 200);
        frame.getContentPane().setLayout(new BorderLayout());
        frame.getContentPane().add(area, BorderLayout.CENTER);
        frame.getContentPane().add(button, BorderLayout.SOUTH);
        area.setText("Hello World");
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("A Menu");
        menuBar.add(menu);
        JMenuItem menuItem = new JMenuItem("A text item");
        menu.add(menuItem);
        menu.addSeparator();
        menuItem = new JMenuItem("hello");
        menu.add(menuItem);
        JMenu subMenu = new JMenu("submenu");
        menuItem = new JMenuItem("sub1");
        subMenu.add(menuItem);
        menuItem = new JMenuItem("sub2");
        subMenu.add(menuItem);
        menu.add(subMenu);
        frame.getContentPane().add(menuBar, BorderLayout.NORTH);
        frame.show();
     public static void main(String[] args) {
     EasyFrame ef = new EasyFrame();
}If I make a System.out.println(frame.getContentPane().getComponentCount());I get 3. But I should dig deeper (with getComponent(2)) to access JMenuBar. But this way I receive a AWT Component / not a JMenuBar Swing component to get its JMenu / and its JMenuItems. And I cannot make it cast to JMenuBar since this walk-through routine should be a universal while(isThereMoreCompenent){} procedure, I don't know when to cast to what (JMenu, JMenuItem, Button and so on).
My problem is that how can I access the JMenuItems one by one, and change e.g. the setEnabled attribute of the "hello" menu?
I hope you can make it clear to me.
Please help if so.