FULL PRODUCT VERSION :
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0-b64)
Java HotSpot(TM) Client VM (build 1.5.0-b64, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
When using the static method Spring.width(), created spring does not track the current size of the component given but the preffered size. That is contrary to the API doc. This is due to the fact that getValue() method inherited form AbstractSpring is not overriden to provide the value. It should say

public int getValue() {
       return size != UNSET ? size : c.getSize().width;
   }

 instead of inherited

public int getValue() {
       return size != UNSET ? size : getPreferredValue();
}


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Use the code in the test case


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
When you run the code and resize the window in any direction, button should resize as well to fill all the internal space.

ACTUAL -
Width and height of the button do not track the changes.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Spring;
import javax.swing.SpringLayout;

/*
 * Created on 12-Oct-2004
 *
 */

/**
 * @author kundrisl
 *
 */
public class SpringLayoutTest extends JFrame {

    public static void main(String[] args) {
        SpringLayoutTest frame = new SpringLayoutTest();
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                if (e!=null) {} /*NOT USED*/
                System.exit(0);
            }
        });
    }

    public SpringLayoutTest() {
        super("SpringLayoutTest");

        Container contentPane = getContentPane();
        contentPane.setLayout(new GridLayout(1,1,1,1));
        
        SpringLayout layout = new SpringLayout();
        JPanel strip = new JPanel(layout);
        strip.setBackground(Color.RED);
        strip.setPreferredSize(new Dimension(100,100));
        contentPane.add(strip);
        
        JButton col1 = new JButton("A");
        strip.add(col1);
        
        SpringLayout.Constraints cons1 = new SpringLayout.Constraints(
                Spring.constant(0),
                Spring.constant(0),
                Spring.width(strip),
                Spring.height(strip)
        );
        layout.addLayoutComponent(col1,cons1);
        
        pack();
        setVisible(true);
    }
}


---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Use your own Spring sublass. Something like this:

=MyWidthSpring.java=====================================
import java.awt.Component;

import javax.swing.Spring;

/*
 * Created on 13-Oct-2004
 *
 */

/**
 * @author kundrisl
 *
 */
public class MyWidthSpring extends Spring {

   Component c;

   protected int size = UNSET;

   public MyWidthSpring(Component c) {
       this.c = c;
   }

   public int getValue() {
       return size != UNSET ? size : c.getSize().width;
   }

   public void setValue(int size) {
       if (size == UNSET) {
           clear();
           return;
       }
       this.size = size;
   }

   protected void clear() {
       size = UNSET;
   }
    public int getMinimumValue() {
        return c.getMinimumSize().width;
    }

    public int getPreferredValue() {
        return c.getPreferredSize().width;
    }

    public int getMaximumValue() {
        // We will be doing arithmetic with the results of this call,
        // so if a returned value is Integer.MAX_VALUE we will get
        // arithmetic overflow. Truncate such values.
        return Math.min(Short.MAX_VALUE, c.getMaximumSize().width);
    }
}
###@###.### 2004-11-08 18:44:12 GMT