Sharing objects across Tabs of a JTabbedPane

Question

I don't know whether this is an Object-Oriented design question or a JTabbedPane question.
I'm pretty new to Java, so be patient!
I wish to have a JTabbedPane with a tab to do 'Import' of data, and a tab to do 'Export' of data (the SAME data which was imported).
How do I share the data between the 2 tabs? It seems the data belongs at the JFrame level, but then how does the data in each tab access it? In other languages I would pass a reference to the data object in the window to each tab. Or how do I get (or set) the data when the tab changes? And how do I know when the tab changes?
I know if I had one tab with an import/export functionality then I could declare the Collection within that panel.
Help!!!
Thanks ;)

Answer 1

here's a starter
import javax.swing.*;
import java.awt.*;
import javax.swing.event.*;
class Testing
  int selectedIndex = 0;
  public void buildGUI()
    final JTabbedPane tp = new JTabbedPane();
    tp.setUI(new javax.swing.plaf.metal.MetalTabbedPaneUI(){
      protected void paintTab(Graphics g,int tabPlacement,Rectangle[] rects,int tabIndex,Rectangle iconRect,Rectangle textRect){
        if(tabIndex == selectedIndex) super.paintTab(g,tabPlacement,rects,tabIndex,iconRect,textRect);
    tp.addChangeListener(new ChangeListener(){
      public void stateChanged(ChangeEvent ce){
        selectedIndex = tp.getSelectedIndex();
    for(int x = 0; x < 5; x++) tp.addTab(""+(char)(x+65),new JPanel());
    tp.setPreferredSize(new Dimension(200,200));
    JFrame f = new JFrame();
    f.getContentPane().add(tp);
    f.pack();
    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();
}