JTree

[karunakaran Perumal]

I Created a jtree .Now i need a method to find whether any element is there in the tree with name x.I want to know is any method is there like this.


Jtree.ischildNode(String name);


thanks

[Craig Wood]

    TreeModel model = tree.getModel();
    int index = model.getIndexOfChild(rootNode, childNode);
    if(index != -1)
        // rootNode contains childNode

[KathySmith SmithL]

I too need to do something like that..
how do I get this value and the index of it, so that I can add more children to it if it is equal to my value??

For example, I have a Vector with objects that have 3 values like
Vector(0) = Obj1 where Obj1(0)=C1, Obj1(1)=F1, Obj1(2)=S1
Vector(1) = Obj2 where Obj2(0)=C1, Obj2(1)=F1, Obj2(2)=S2
Vector(2) = Obj3 where Obj3(0)=C2, Obj3(1)=F2, Obj3(2)=S2
Vector(3) = Obj4 where Obj4(0)=C1, Obj4(1)=F2, Obj4(2)=S1

now how will I construct a tree from this? I'm trying a lot to get this working.. but somehow the constructed tree doesn't exactly match my requirement. Can somebody please help me..
the output tree I need is :
Root
-C1
_|-F1
____|-S1
____|-S2
_|-F2
____|-S1
-C2
_|-F2
____|-S2

and so on..
[ October 22, 2004: Message edited by: KathySmith SmithL ]

[Craig Wood]

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.util.List;
import javax.swing.*;
import javax.swing.tree.*;
 
public class TreeSearch
{
    JLabel resultLabel;
 
    public TreeSearch()
    {
        JTree tree = createTree();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(getSearchPanel(tree), "North");
        f.getContentPane().add(new JScrollPane(tree));
        f.getContentPane().add(getResultLabel(), "South");
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private JTree createTree()
    {
        String[] names = {
          // branches   |<--      child leaf nodes       -->|
            "hawks",   "gray",    "red-tailed", "rough-legged",
            "falcons", "harrier", "kestrel",    "kite", 
            "owls",    "barred",  "saw-whet",   "snowy"
        };
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("birds");
        DefaultMutableTreeNode[] nodes = new DefaultMutableTreeNode[12];
        for(int j = 0; j < nodes.length; j++)
            nodes[j] = new DefaultMutableTreeNode(names[j]);
        for(int j = 0; j < 9; j += 4)
        {
            root.insert(nodes[j], j % 3);
            for(int k = j + 1; k < j + 4; k++)
                nodes[j].insert(nodes[k], k - j - 1);
        }
        DefaultTreeModel model = new DefaultTreeModel(root);
        return new JTree(model);
    }
 
    private JPanel getSearchPanel(final JTree tree)
    {
        final JTextField tf = new JTextField(12);
        JButton search = new JButton("search for name");
        search.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                String text = tf.getText();
                String s = "no, the name \"" + text + "\" is not found in tree";
                if(search(tree, text))
                    s = "yes, the name \"" + text + "\" is found in the tree";
                resultLabel.setText(s);
            }
        });
        JPanel panel = new JPanel();
        panel.add(new JLabel("search name"));
        panel.add(tf);
        panel.add(search);
        return panel;
    }
 
    private JLabel getResultLabel()
    {
        resultLabel = new JLabel();
        resultLabel.setHorizontalAlignment(JLabel.CENTER);
        Dimension d = resultLabel.getPreferredSize();
        d.height = 20;
        resultLabel.setPreferredSize(d);
        return resultLabel;
    }
 
    private boolean search(JTree tree, String text)
    {
        DefaultMutableTreeNode root =
            (DefaultMutableTreeNode)tree.getModel().getRoot();
        Enumeration e = root.breadthFirstEnumeration();
        while(e.hasMoreElements())
        {
            DefaultMutableTreeNode node = (DefaultMutableTreeNode)e.nextElement();
            String userObject = node.getUserObject().toString();
            //System.out.println("userObject = " + userObject);
            if(userObject.equals(text))
                return true;
        }
        return false;
    }
 
    public static void main(String[] args)
    {
        new TreeSearch();
    }
}

[Craig Wood]

import java.awt.*;
import javax.swing.*;
import javax.swing.tree.*;
 
public class MakingATree
{
    public MakingATree()
    {
        JTree tree = createTree();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(tree);
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private JTree createTree()
    {
        DefaultMutableTreeNode
            root = new DefaultMutableTreeNode("root"),
                c1 = new DefaultMutableTreeNode("c1"),
                    f1 = new DefaultMutableTreeNode("f1"),
                        s1 = new DefaultMutableTreeNode("s1"),
                        s2 = new DefaultMutableTreeNode("s2"),
                    f2 = new DefaultMutableTreeNode("f2"),
                        s3 = new DefaultMutableTreeNode("s3"),
                c2 = new DefaultMutableTreeNode("c2"),
                    f3 = new DefaultMutableTreeNode("f3"),
                        s4 = new DefaultMutableTreeNode("s4");
        root.insert(c1, 0);
        c1.insert(f1, 0);
        f1.insert(s1, 0);
        f1.insert(s2, 1);
        c1.insert(f2, 1);
        f2.insert(s3, 0);
        root.insert(c2, 1);
        c2.insert(f3, 0);
        f3.insert(s4, 0);
        DefaultTreeModel model = new DefaultTreeModel(root);
        return new JTree(model);
    }
 
    public static void main(String[] args)
    {
        new MakingATree();
    }
}

[ October 23, 2004: Message edited by: Craig Wood ]

[KathySmith SmithL]

Originally posted by Craig Wood:

Thanks for the code Craig.. but u have hardcoded the values.. so it is easy to directly add the values.. but when I have dynamically input values, how do I do the same ?? I don't even know the order in which I'll get the values.. like C1 may first come and then C2 may come in the vector that contains the objects and then again I might get a C1-F1-S2 value.
[ October 23, 2004: Message edited by: KathySmith SmithL ]

[Craig Wood]

import java.awt.*;
import java.awt.event.*;
import java.util.Enumeration;
import javax.swing.*;
import javax.swing.tree.*;
 
public class NodeInsertion
{
    DefaultMutableTreeNode lastMatch;  // state for locateNodes method
 
    public NodeInsertion()
    {
        JTree tree = createTree();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(getEntryPanel(tree), "North");
        f.getContentPane().add(new JScrollPane(tree));
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
 
    private JTree createTree()
    {
        DefaultMutableTreeNode
            root = new DefaultMutableTreeNode("root"),
                c1 = new DefaultMutableTreeNode("c1"),
                    f1 = new DefaultMutableTreeNode("f1"),
                        s1 = new DefaultMutableTreeNode("s1"),
                        s2 = new DefaultMutableTreeNode("s2"),
                    f2 = new DefaultMutableTreeNode("f2"),
                        s3 = new DefaultMutableTreeNode("s3"),
                c2 = new DefaultMutableTreeNode("c2"),
                    f3 = new DefaultMutableTreeNode("f3"),
                        s4 = new DefaultMutableTreeNode("s4");
        root.insert(c1, 0);
        c1.insert(f1, 0);
        f1.insert(s1, 0);
        f1.insert(s2, 1);
        c1.insert(f2, 1);
        f2.insert(s3, 0);
        root.insert(c2, 1);
        c2.insert(f3, 0);
        f3.insert(s4, 0);
        DefaultTreeModel model = new DefaultTreeModel(root);
        JTree tree = new JTree(model);
        expandAllNodes(tree, root);
        return tree;
    }
 
    /**
     * expand tree nodes for ease in testing
     */
    private void expandAllNodes(JTree tree, DefaultMutableTreeNode node)
    {
        tree.expandPath(new TreePath(node.getPath()));
        if(node.getChildCount() >= 0)
        {
            Enumeration e = node.children();
            while(e.hasMoreElements())
            {
                DefaultMutableTreeNode n =
                    (DefaultMutableTreeNode)e.nextElement();
                expandAllNodes(tree, n);
            }
        }
    }
 
    /**
     * ui panel goes in north section of gui
     */
    private JPanel getEntryPanel(final JTree tree)
    {
        /** enter nodes as three comma-separated strings **
         **   parsed into an array with (String) split   **/
        final JTextField tf = new JTextField("c2,f3,s5", 8);
        tf.selectAll();
        JButton insert = new JButton("insert nodes");
        insert.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                String[] nodeNames = tf.getText().split(",");
                insertNodesByName(tree, nodeNames);
            }
        });
        JPanel panel = new JPanel();
        panel.add(new JLabel("nodes to insert"));
        panel.add(tf);
        panel.add(insert);
        return panel;
    }
 
    /**
     * entry point for insertion of new nodes into JTree
     */
    private void insertNodesByName(JTree tree, String[] nodeNames)
    {
        DefaultMutableTreeNode root =
            (DefaultMutableTreeNode)tree.getModel().getRoot();
        lastMatch = null;
        String[] nodeNamesToAdd = null;
        locateNodes(tree, root, nodeNames, 0);
        if(lastMatch == root)                        // no matches, add to root
            nodeNamesToAdd = nodeNames;
        else                                         // prepare new name array
        {
            String userObject = lastMatch.getUserObject().toString();
            for(int j = 0; j < nodeNames.length; j++)
                if(userObject.equals(nodeNames[j]))
                {
                    int length = nodeNames.length - j - 1;
                    if(length == 0)  // nothing to insert
                        return;
                    nodeNamesToAdd = new String[length];
                    System.arraycopy(nodeNames, j + 1, nodeNamesToAdd, 0, length);
                    break;
                }
        }
        insertNewNodes(tree, lastMatch, nodeNamesToAdd);
    }
 
    /**
     * recursive method finds node in JTree that
     * the new children will be inserted into
     */
    private void locateNodes(JTree tree, DefaultMutableTreeNode node,
                             String[] names, int depth)
    {
        String userObject = node.getUserObject().toString();
        if(userObject.equals(names[depth]) ||
               node.equals(tree.getModel().getRoot()))
        {
            lastMatch = node;
            if(node.getChildCount() >= 0)
            {
                // one-time adjustment of depth counter so [depth == 0]
                // after tree root passes through on initial run
                if(node.equals(tree.getModel().getRoot()))
                    depth--;
                Enumeration e = node.children();
                while(e.hasMoreElements())
                {
                    DefaultMutableTreeNode n =
                        (DefaultMutableTreeNode)e.nextElement();
                    locateNodes(tree, n, names, depth + 1);
                }
            }
        }
    }
 
    /**
     * assemble the new nodes from names[] and insert them into node
     */
    private void insertNewNodes(JTree tree, DefaultMutableTreeNode node,
                                String[] names)
    {
        if(!node.getAllowsChildren())
            node.setAllowsChildren(true);
        DefaultTreeModel model = (DefaultTreeModel)tree.getModel();
        int nodeIndex = getInsertionIndex(node, names[0]);
        DefaultMutableTreeNode[] nodes = new DefaultMutableTreeNode[names.length];
        int nameIndex = 0;
        while(nameIndex < names.length)
        {
            nodes[nameIndex] = new DefaultMutableTreeNode(names[nameIndex]);
            if(nameIndex > 0)
                nodes[nameIndex - 1].add(nodes[nameIndex]);
            nameIndex++;
        }
        model.insertNodeInto(nodes[0], node, nodeIndex);
        model.nodeChanged(node);
    }
 
    /**
     * if node has children, determine index for first new child
     */
    private int getInsertionIndex(DefaultMutableTreeNode node, String name)
    {
        Enumeration e = node.children();
        int count = 0;
        while(e.hasMoreElements())
        {
            DefaultMutableTreeNode n = (DefaultMutableTreeNode)e.nextElement();
            String userObject = n.getUserObject().toString();
            if(userObject.compareTo(name) > 0)
                break;
            count++;
        }
        return count;
    }
 
    public static void main(String[] args)
    {
        new NodeInsertion();
    }
}