BoxLayout sizing accross the box

Question

I find the behaviour of BoxLayout in the "cross" direction (i.e. side to side for a vertical box, vertical for a horizontal box) confusing.
For example I've just put together a veritcal box with three buttons whose natural sizes differ, with glue between them. I'd expect that the buttons would be stretched horizontally to the width of the widest, but they're just left justified. Even if I copy the preferred size from the widest button to the others it has no effect. Think I'll have to switch to a SpringLayout to give me the degree of control I need.
How can I force these widths to match in a BoxLayout? I've done a lot of fumbling about with this.

Answer 1

boxlayout respects maximumSize, and, at least in 1.5.0_05, it seems to set
everything to their maximumSize. the logic seems strange.
import javax.swing.*;
import java.awt.*;
class Testing
  public void buildGUI()
    JPanel p = new JPanel();
    p.setLayout(new BoxLayout(p,BoxLayout.Y_AXIS));
    JButton b1 = new JButton("OK");
    JButton b2 = new JButton("OKOKOK");
    JButton b3 = new JButton("OKOKOKOKOKOK");
    b1.setMaximumSize(b3.getPreferredSize());
    b2.setMaximumSize(b3.getPreferredSize());
    p.add(b1);p.add(b2);p.add(b3);
    JFrame f = new JFrame();
    f.getContentPane().add(p);
    //f.pack();
    f.setSize(600,400);
    f.setLocationRelativeTo(null);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
  public static void main(String[] args)
    SwingUtilities.invokeLater(new Runnable(){
      public void run(){
        new Testing().buildGUI();
}