Help : Usage of FocusTraversalPolicy in 1.4.2_07

Question

Dear All,
My existing application written in Jdk 1.3.1_15.Now,upgrading to 1.4.2_07.
Compilation in 1.4.2_07 throws so many warnings about the deprecated method setNextFocusableComponent(Component c);
Usage of setNextFocusableComponent
Assume 10 components are added in a container like Panel.
We can set the focus in random manner like comp1 ->comp3->comp5->comp4 etc.
So, the coding will be like,
comp1.setNextFocusablecomponent(comp3);
comp3.setNextFocusableComponent(comp5);
comp5.setNextFocusableComponent(comp4); etc ..etc..
Since this particular method is deprecated in 1.4.2_07, i get warnings.
I don't prefer this warnings and need clean compilation.
The alternative solution is implementing FocusTraversalPolicy class.
FocusTraversalPolicy class
It is an abstract class has subclasses ContainerOrderFocusTraversalPolicy and InternalFrameFocusTraversalPolicy .
I have an option to set ContainerOrderFocusTraversalPolicy to my container by the following line .
ContainerOrderFocusTraversalPolicy CTP= new ContainerOrderFocusTraversalPolicy();
panel.setFocusTraversalPolicy(CTP);
The above lines of coding let componets have the sequential order of focus like comp1->comp2->comp3 etc...
But i need to assign the random order of focus to components.
Could anyone please help me in this regard ? what i need to do further ?
Please help me to understand how to use this policy class for my need.Appreciate your responses.
Sample test program
import java.awt.*;
import javax.swing.*;
public class TestPanel {
public static void main(String args[]) {
JFrame frame = new JFrame();
Container content = frame.getContentPane();
JLabel l1,l2,l3,l4,l5;
JTextField jt1,jt2,jt3;
JComboBox jcb1;
JCheckBox jchb1;
JPanel jp= new JPanel();
l1=new JLabel();
l1.setText("name");
l2=new JLabel();
l2.setText("Age");
l3=new JLabel();
l3.setText("Qualification");
l4=new JLabel();
l4.setText("Male - Yes");
l5=new JLabel();
l5.setText("DOB");
jt1=new JTextField(10);
jt2=new JTextField(20);
jt3=new JTextField(20);
jcb1=new JComboBox();
jchb1=new JCheckBox();
jp.add(l1);
jp.add(jt1);
jp.add(l2);
jp.add(jt2);
jp.add(l3);
jp.add(jcb1);
jp.add(l4);
jp.add(jchb1);
jp.add(l5);
jp.add(jt3);
// deprecated methods commented to avoid warnings in 1.4.2_07
/* jt1.setNextFocusableComponent(jcb1);
jcb1.setNextFocusableComponent(jt3);
jt3.setNextFocusableComponent(jchb1);
jchb1.setNextFocusableComponent(jt2);
jt2.setNextFocusableComponent(jt1);*/
// New policy class
ContainerOrderFocusTraversalPolicy CTP= new ContainerOrderFocusTraversalPolicy();
// setting the policy class in panel
jp.setFocusTraversalPolicy(CTP);
content.add(jp, BorderLayout.CENTER);
frame.pack();
frame.show();
jp.getComponent(1).requestFocusInWindow();
Thanks and Regards
David Menfields

Answer 1

You need to actually write your own FocusTraversalPolicy class.
It's actually pretty easy - just subclass FocusTraversalPolicy and override all the methods. You need to have your own algorithm for determining the next/first/last/etc components and after a short look at your code my guess would be to hold a reference to each component on your form in an array in the order you want the focus to move in and then you can easily return the "next" or "previous" component by looking up the array.
Some of the methods can call others - e.g. getDefaultComponent, getFirstComponent, and getInitialComponent usually all return the same value.
Regards,
Tim