How can I put JTree into drop-down List of JCombobox

Question

I want to create a drop-down list which shows a list of nodes. When the user clicks on a node, it should open to show the leafs. Clicking on a leaf should close the ComboboxPopup and show its value. Creating a renderer only represent my tree, but I can't trap the events.
Here is my simplified code.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.border.*;
import java.util.*;
public class ComboBoxTreeDemo  extends JPanel
     static JFrame frame;
     ComboBoxRenderer renderer;
     JTree tree;
     public ComboBoxTreeDemo()
          setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
          DefaultMutableTreeNode root =  new DefaultMutableTreeNode("top");
          DefaultMutableTreeNode sub1 =  new DefaultMutableTreeNode("sub1");
          DefaultMutableTreeNode sub2 =  new DefaultMutableTreeNode("sub2");
          root.add(sub1);
          root.add(sub2);
          tree = new JTree(root);
          String[] string = {"1" };
          JComboBox jcb = new JComboBox(string);
          renderer = new ComboBoxRenderer(this);
          jcb.setPreferredSize(new Dimension(100,22));
          jcb.setEditable(true);
          jcb.setRenderer(renderer);
          JPanel jpa = new JPanel();
          jpa.setLayout(new BoxLayout(jpa, BoxLayout.PAGE_AXIS));
          jpa.setAlignmentX(Component.LEFT_ALIGNMENT);
          jpa.add(jcb);
          add(jpa);
          setBorder(BorderFactory.createEmptyBorder(10,10,10,10));
     private static void createAndShowGUI()
          JFrame.setDefaultLookAndFeelDecorated(true);
          JFrame frame = new JFrame("ComboBoxTreeDemo");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          JComponent newContentPane = new ComboBoxTreeDemo();
          newContentPane.setOpaque(true);
          frame.setContentPane(newContentPane);
          frame.pack();
          frame.setVisible(true);
      class ComboBoxRenderer extends JPanel implements ListCellRenderer
          ComboBoxTreeDemo cbt;
          public ComboBoxRenderer(ComboBoxTreeDemo cbt)
               this.cbt = cbt;
               setLayout(new BorderLayout());
               add(cbt.tree);
          public Component getListCellRendererComponent(JList list,Object value,int index, boolean isSelected,boolean cellHasFocus)
               return this;
     public static void main(String[] args)
          javax.swing.SwingUtilities.invokeLater(new Runnable()
               public void run()
                    createAndShowGUI();
}

Answer 1

Thank you for the excellent reference Peddi. I had played with the OAMessageChoiceBean component yesterday, but I was able to tell from your instructions that "Picklist Display Attribute" and "Picklist Value Attribute" really are not for binding to the database EO. That was the key piece of information that had me confused.
In addition to adding the messageChoice component to the page, I needed to write some code to synchronize the picklist value with the corresponding code value, which I placed in am OAFormValueBean (hidden form field) which I could then bind to my application's database EO in the controller, running in the processFormRequest procedure:
/** Synchronize the catalog code with the selected catalog name */
protected void syncCatalogValues(OAPageContext pageContext,
OAWebBean webBean, MyApplicationAMImpl am) {   
OAMessageChoiceBean mcb =
(OAMessageChoiceBean) webBean.findChildRecursive("CatalogName");
OAFormValueBean cc =
(OAFormValueBean) webBean.findChildRecursive("CatalogCode");
String catalogDescription = mcb.getText(pageContext);
if (catalogDescription != null) {
String catalogCode = am.getCatalogCode(catalogDescription);
cc.setValue(pageContext, catalogCode);
Along with a little code to get the catalogCode value from the LOVVO, that's all it took.
Thanks again. This was a great help.
Pete