JTree Focus Test

import java.awt.Dimension;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;

import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JTree;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeSelectionModel;

public class JTreeFocusTest extends JFrame{
    private static final long serialVersionUID = 1L;
    public JTreeFocusTest() {
        super("JTree Focus Test");
        JPanel panel = new JPanel(true);
        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
        MyTree tree = new MyTree();
        panel.add(tree);
        panel.add(Box.createVerticalStrut(20));
        panel.add(new MyTextField(tree));
        panel.add(Box.createVerticalStrut(20));
        panel.add(new JTextField(30));
        getContentPane().add(panel);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
    }

    public static void main(String[] args){
        new JTreeFocusTest();
    }
}

class MyTree extends JTree{
    private static final long serialVersionUID = 1L;
    public MyTree() {
        DefaultMutableTreeNode root = new DefaultMutableTreeNode(new MyNode("Root", "Root"));
        DefaultMutableTreeNode child1 = new DefaultMutableTreeNode(new MyNode("Child 1", "DOC122122"));
        root.add(child1);
        DefaultMutableTreeNode child2 = new DefaultMutableTreeNode(new MyNode("Child 2", "DOC134342"));
        root.add(child2);
        DefaultTreeModel model = new DefaultTreeModel(root, true);
        setModel(model);
        getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
        setSelectionPath(getPathForRow(0));
    }
}

class MyTextField extends JTextField implements FocusListener, TreeSelectionListener{
    private static final long serialVersionUID = 1L;
    private MyTree tree;
    public MyTextField(MyTree tree) {
        this.tree = tree;
        setText("Some");
        addFocusListener(this);
        this.tree.addTreeSelectionListener(this);
        Dimension dim = new Dimension(200, 20);
        setPreferredSize(dim);
        setMaximumSize(dim);
        setMinimumSize(dim);
    }
    @Override
    public void focusGained(FocusEvent e) {System.out.println("TextField gained focus");}
    @Override
    public void focusLost(FocusEvent e) {
        getSelectedNodeUserObj().setValue(getText());
    }
    @Override
    public void valueChanged(TreeSelectionEvent e) {
        setText(getSelectedNodeUserObj().getValue());
    }
    private MyNode getSelectedNodeUserObj(){
        return ((MyNode)((DefaultMutableTreeNode)this.tree.getSelectionPath().getLastPathComponent()).getUserObject());
    }
}

class MyNode{
    private String label = "";
    private String value = "";

    public MyNode(String label, String value) {
        this.label = label;
        this.value = value;
    }
    public void setValue(String value){
        this.value = value;
    }
    public String getValue(){
        return value;
    }
    public String toString(){
        return label;
    }
}