Example of TreeTable

The example program about TreeTable discussed in Sun’s article Creating TreeTables: Part 2 adds unnecessary complexity. The following is a much simpler one and will get you started much quicker.

Prerequisite: Download src.zip from the above url and compile the with both programs presented here.

Main.java:

import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.*;
import javax.swing.table.*;
import javax.swing.tree.*;
import java.awt.*;
import java.awt.event.*;
import java.text.NumberFormat;
 
public class Main extends JFrame {
   protected MyTreeTableModel  model;
   protected JTreeTable        treeTable;
 
   public Main() {
      super("Main");
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
 
      model     = new MyTreeTableModel();
      treeTable = new JTreeTable(model);
 
      getContentPane().add(new JScrollPane(treeTable));
 
      try {
         UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
         SwingUtilities.updateComponentTreeUI(this);
      }
      catch(Exception e) {
         e.printStackTrace();
      }
 
      pack();
      show();
   }
 
   public static void main(String[] args) {
      new Main();
   }
}

MyTreeTableModel.java:

import java.io.IOException;
import java.io.File;
import java.util.Date;
import java.util.Stack;
import javax.swing.SwingUtilities;
import javax.swing.tree.TreePath;
import java.util.*;
 
public class MyTreeTableModel extends AbstractTreeTableModel {
 
   // Names of the columns.
   static protected String[] cNames = {"Column 1", "Column 2", 
                                       "Column 3", "Column 4"};
   // Types of the columns.
   static protected Class[]  cTypes = { TreeTableModel.class, String.class, 
                                        String.class, String.class };
   static Entry rootEntry;  
 
   /******** Entry class represents the parent and leaf nodes **********/
   static class Entry {
      private String name; 
      private boolean isLeaf;
      private Vector children = new Vector();
 
      public Entry(String name, boolean isLeaf) {
         this.name = name;
         this.isLeaf = isLeaf;
      }
 
      public Vector getChildren() {
         return children;
      }
 
      public boolean isLeaf() {
         return isLeaf;
      }
 
      public String getName() {
         return name;
      }
 
      public String toString() {
         return name;
      }
   }
 
   static {
      rootEntry = new Entry("rootentry", false);
      rootEntry.getChildren().addElement(new Entry("test1", true));
      rootEntry.getChildren().addElement(new Entry("test2", true));

      Entry subEntry1 = new Entry("subentry1", false);
      subEntry1.getChildren().addElement(new Entry("test3", true));
      subEntry1.getChildren().addElement(new Entry("test4", true));
      Entry subEntry2 = new Entry("subentry2", false);
      subEntry2.getChildren().addElement(new Entry("test5", true));
      subEntry2.getChildren().addElement(new Entry("test6", true));
      rootEntry.getChildren().addElement(subEntry1);
      rootEntry.getChildren().addElement(subEntry2); 
   }
   /*************************************/
 
   public MyTreeTableModel() { 
      super(rootEntry);
   }
 
   public int getChildCount(Object node) { 
      if (!((Entry) node).isLeaf()) {
         return ((Entry) node).getChildren().size();
      }
      return 0;
   }
 
   public Object getChild(Object node, int i) { 
      return ((Entry) node).getChildren().elementAt(i);
   }
 
   public boolean isLeaf(Object node) {
      return ((Entry) node).isLeaf();
   }
 
   public int getColumnCount() {
      return cNames.length;
   }
 
   public String getColumnName(int column) {
      return cNames[column];
   } 
 
   public Class getColumnClass(int column) {
      return cTypes[column];
   }
 
   public Object getValueAt(Object node, int column) {
      switch(column) {
         case 0:
            return node;
         case 1:
            return "value1";
         case 2:
            return "value2";
         case 3:
            return "value3";
      }
   
      return null; 
   }
}

Having a JTextArea as a node of a JTree

Main.java:

import javax.swing.border.*;
import javax.swing.event.*;
import javax.swing.tree.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.net.*;
 
public class Main extends JFrame
{
   public Main() {
      DefaultMutableTreeNode root = createNodes();
      JTree tree = new JTree(root);
      //tree.setCellEditor(new DefaultCellEditor(new JTextField())); 
      tree.setCellRenderer(new DelegateDefaultCellRenderer());
      tree.setRowHeight(-1);
 
      getContentPane().add(new JScrollPane(tree));
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   }
 
   public static DefaultMutableTreeNode createNodes() {
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("Java");
      
      DefaultMutableTreeNode j2se = new DefaultMutableTreeNode("J2SE");
      DefaultMutableTreeNode j2ee = new DefaultMutableTreeNode("J2EE");
      DefaultMutableTreeNode j2me = new DefaultMutableTreeNode("J2ME");
 
      j2se.add(new DefaultMutableTreeNode("http://java.sun.com/j2se/"));
      j2ee.add(new DefaultMutableTreeNode("http://java.sun.com/j2ee/"));
      j2me.add(new DefaultMutableTreeNode("http://java.sun.com/j2me/"));
 
      root.add(j2se);
      root.add(j2ee);
      root.add(j2me);
 
      return root;
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(400, 400);
      main.setVisible(true);
   }
}
 
class DelegateDefaultCellRenderer extends DefaultTreeCellRenderer 
{
   TextAreaRenderer taRenderer = new TextAreaRenderer();
 
   public DelegateDefaultCellRenderer() {
      taRenderer.setBackgroundNonSelectionColor(getBackgroundNonSelectionColor());
      taRenderer.setBackgroundSelectionColor(getBackgroundSelectionColor());
      taRenderer.setTextNonSelectionColor(getTextNonSelectionColor());  
      taRenderer.setTextSelectionColor(getTextSelectionColor()); 
   }
 
   public Component getTreeCellRendererComponent(JTree tree, Object value,
                                  boolean selected, boolean expanded, boolean leaf,
                                  int row, boolean hasFocus)
   {
      if (!leaf) {
         return super.getTreeCellRendererComponent(tree, value, selected, 
                                                   expanded, leaf, row, hasFocus);
      }
      else {
         return taRenderer.getTreeCellRendererComponent(tree, value, selected, 
                                                        expanded, leaf, row, hasFocus);
      }
   }
}   
 
class TextAreaRenderer extends JScrollPane implements TreeCellRenderer
{
   JTextArea textarea;
   Color backgroundNonSelectionColor;
   Color backgroundSelectionColor;
   Color textNonSelectionColor;
   Color textSelectionColor;
 
   public TextAreaRenderer() {
      textarea = new JTextArea(3, 40);
      textarea.setLineWrap(true);
      textarea.setWrapStyleWord(true);
      textarea.setBorder(new TitledBorder("This is a JTextArea"));
      getViewport().add(textarea);
   }
 
   public void setBackgroundNonSelectionColor(Color c) {
      this.backgroundNonSelectionColor = c;
   }
 
   public void setBackgroundSelectionColor(Color c) {
      this.backgroundSelectionColor = c;
   }
  
   public void setTextNonSelectionColor(Color c) {
      this.textNonSelectionColor = c;
   }
  
   public void setTextSelectionColor(Color c) {
      this.textSelectionColor = c;
   }
 
   public Component getTreeCellRendererComponent(JTree tree, Object value,
                                  boolean selected, boolean expanded, boolean leaf,
                                  int row, boolean hasFocus)
   {
      if (selected) {
         setForeground(textSelectionColor);
         setBackground(backgroundSelectionColor);
         textarea.setForeground(textSelectionColor);
         textarea.setBackground(backgroundSelectionColor);
      } else {
         setForeground(textNonSelectionColor);
         setBackground(backgroundNonSelectionColor);
         textarea.setForeground(textNonSelectionColor);
         textarea.setBackground(backgroundNonSelectionColor);
      }
 
      textarea.setText(""+((DefaultMutableTreeNode) value).getUserObject()); 
      textarea.setCaretPosition(0);
 
      return this;
   }
}

Preventing a JTree to be expanded or collapsed

Use the TreeWillExpandListener interface!

The following example allows expanding of nodes, but prevents collapsing.

Main.java:

import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
 
public class Main extends JFrame
{
   public Main() {
      DefaultMutableTreeNode root = createNodes();
      JTree tree = new JTree(root);
 
      tree.addTreeWillExpandListener(new TreeWillExpandListener() {
         public void treeWillCollapse(TreeExpansionEvent event) 
                            throws ExpandVetoException 
         {
            // prevent collapsing
            throw new ExpandVetoException(event);
 
         }
         public void treeWillExpand(TreeExpansionEvent event) 
                            throws ExpandVetoException 
         {
            // do nothing
         }
      });
 
      getContentPane().add(new JScrollPane(tree));
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   }
 
   public static DefaultMutableTreeNode createNodes() {
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("Java");
      
      DefaultMutableTreeNode j2se = new DefaultMutableTreeNode("J2SE");
      DefaultMutableTreeNode j2ee = new DefaultMutableTreeNode("J2EE");
      DefaultMutableTreeNode j2me = new DefaultMutableTreeNode("J2ME");
 
      j2se.add(new DefaultMutableTreeNode("http://java.sun.com/j2se/"));
      j2ee.add(new DefaultMutableTreeNode("http://java.sun.com/j2ee/"));
      j2me.add(new DefaultMutableTreeNode("http://java.sun.com/j2me/"));
 
      root.add(j2se);
      root.add(j2ee);
      root.add(j2me);
 
      return root;
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(400, 400);
      main.setVisible(true);
   }
}

Allowing for multiple selections in a JTree

Use TreeSelectionModel.DISCONTIGUOUS_TREE_SELECTION!

Main.java:

import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
 
public class Main extends JFrame
{
   public Main() {
      DefaultMutableTreeNode root = createNodes();
      final JTree tree = new JTree(root);
 
      TreeSelectionModel model = new DefaultTreeSelectionModel();
      model.setSelectionMode(TreeSelectionModel.DISCONTIGUOUS_TREE_SELECTION);
      tree.setSelectionModel(model);
 
      JButton button = new JButton("Display selected values on stdout");
      button.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            TreePath[] treePaths = tree.getSelectionPaths();    
            for (int i=0; i<treePaths.length; i++) {
               System.out.println(treePaths[i].getLastPathComponent());    
            }
         }
      });
 
      getContentPane().setLayout(new BorderLayout());
      getContentPane().add(BorderLayout.CENTER, new JScrollPane(tree));
      getContentPane().add(BorderLayout.SOUTH, button);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   }
 
   public static DefaultMutableTreeNode createNodes() {
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("Java");
      
      DefaultMutableTreeNode j2se = new DefaultMutableTreeNode("J2SE");
      DefaultMutableTreeNode j2ee = new DefaultMutableTreeNode("J2EE");
      DefaultMutableTreeNode j2me = new DefaultMutableTreeNode("J2ME");
 
      j2se.add(new DefaultMutableTreeNode("http://java.sun.com/j2se/"));
      j2ee.add(new DefaultMutableTreeNode("http://java.sun.com/j2ee/"));
      j2me.add(new DefaultMutableTreeNode("http://java.sun.com/j2me/"));
 
      root.add(j2se);
      root.add(j2ee);
      root.add(j2me);
 
      return root;
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(400, 400);
      main.setVisible(true);
   }
}