searching in JTree

[SValmont2000]

Hey @ll,

I have a problem and am somewhat stuck. I have a JTree, with the DefaultTreeModel. I have a DefaultMutableTreeNode where othere Def.Mut.TN are attached. How can I get a specific TreeNode, e.g. in my TreeNodes are always Strings stored, so how can I get the TreeNode with an specific String.

Thanks for the help.

S. V.

 

[toolkit]

The DefaultMutableTreeNode class defines two public methods which may be of use to you:

public java.util.Enumeration breadthFirstEnumeration();
public java.util.Enumeration depthFirstEnumeration();

So I guess you can find the node you want with code similar to:

public DefaultMutableTreeNode findNode( DefaultMutableTreeNode root, String search ) {

    Enumeration nodeEnumeration =
        root.breadthFirstEnumeration();
    while( nodeEnumeration.hasMoreElements() ) {
        DefaultMutableTreeNode node =
            (DefaultMutableTreeNode)nodeEnumeration.nextElement();
        String found = (String)node.getUserObject();
        if( search.equals( found ) ) {
            return node;
        }
    }
    return null;
}

Note, I haven't actually tested this code Hope it works for you... Cheers, Neil

 

[toolkit]

A more complete code example.

import java.awt.*;
import javax.swing.*;
import javax.swing.tree.*;
import java.util.Enumeration;

public class TestTree extends JFrame {

  private JTree jTree;
  DefaultTreeModel defaultTreeModel;

  public TestTree() {
    super( "Test Tree" );
    setSize( 600, 450 );
  }

  public void buildTree( DefaultMutableTreeNode root ) {
    // tree to look like:
    // root
    //  a -> b c
    //  A -> B C
    DefaultMutableTreeNode a = new DefaultMutableTreeNode( "a" );
    DefaultMutableTreeNode b = new DefaultMutableTreeNode( "b" );
    DefaultMutableTreeNode c = new DefaultMutableTreeNode( "c" );

    DefaultMutableTreeNode A = new DefaultMutableTreeNode( "A" );
    DefaultMutableTreeNode B = new DefaultMutableTreeNode( "B" );
    DefaultMutableTreeNode C = new DefaultMutableTreeNode( "C" );

    a.add( b );
    a.add( c );
    root.add( a );

    A.add( B );
    A.add( C );
    root.add( A );
  }

  public void init( String search )  {
    DefaultMutableTreeNode root = new DefaultMutableTreeNode( "root" );
    buildTree( root );
    defaultTreeModel = new DefaultTreeModel( root );
    jTree = new JTree( defaultTreeModel );
    getContentPane().add( new JScrollPane( jTree ), BorderLayout.CENTER );
    DefaultMutableTreeNode foundNode = findNode( root, search );
    TreePath path = new TreePath( foundNode.getPath() );
    System.out.println( "path: " + path.toString() );
    jTree.setEditable( true );
    jTree.makeVisible( path );
    jTree.setSelectionPath( path );
  }

  public DefaultMutableTreeNode findNode( DefaultMutableTreeNode root, String search ) {
    Enumeration nodeEnumeration = root.breadthFirstEnumeration();
    while( nodeEnumeration.hasMoreElements() ) {
      DefaultMutableTreeNode node =
        (DefaultMutableTreeNode)nodeEnumeration.nextElement();
      String found = (String)node.getUserObject();
      if( search.equals( found ) ) {
        return node;
      }
    }
    return null;
  }

  public static void main( String[] args ) {
    try {
      if( args.length != 1 ) {
        System.out.println(
          "Usage: java TestTree " +
          "[search for node]" );
        System.exit(0);
      }
      TestTree testTree = new TestTree();
      testTree.init( args[0] );
      testTree.setVisible( true );
    } catch( Exception e ) {
      e.printStackTrace();
    }
  }
}

Cheers, Neil