// Uses Internet Explorer to programmatically retrieve contents
// of a web-site, walk the tree-structure of the HTML (DOM)
// and display the structure in a JTree.

import iexplorer.InternetExplorer; 
import iexplorer.IWebBrowserApp;  

import mshtml.IHTMLElement;
import mshtml.IHTMLElementCollection;
import mshtml.IHTMLDocument3;
import ezjcom.JComVariant;
import ezjcom.JComObject;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTree;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import java.awt.GridLayout;
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.BorderLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.DefaultMutableTreeNode;

public class TreeWalk extends JFrame {

    IWebBrowserApp app = null;
    WebLoadListener webLoadListener;

    DefaultMutableTreeNode root = 
            new DefaultMutableTreeNode( "Enter URL and click Navigate" );
    JTree tree = new JTree( root );
    JTextField url = new JTextField( 24 );

    static final int FRAME_WIDTH = 600;
    static final int FRAME_HEIGHT = 400;

    public TreeWalk( String title )
    {
        super( title );
    }

    // This method is called when the Navigate button is clicked.
    // The URL is loaded, its contents are analyzed and displayed
    // in a tree structure.

    void onButtonClick()
    {
      try {
        String urlText = url.getText();
        root.setUserObject( urlText );

        // Navigate to the URL typed.
        System.out.println( "Retrieving " + urlText );
        webLoadListener.initialize();
        synchronized ( webLoadListener ) {
            app.Navigate( urlText );
            webLoadListener.wait();
        }
        System.out.println( "Examining contents of " + urlText );
 
        // Walk the HTML tree
        htmlTreeWalk();
        ((DefaultTreeModel) tree.getModel()).reload();

      } catch (Exception ex) {
        ex.printStackTrace();
      }
    }

    // Initialize Internet Explorer and GUI
    void initialize()
    {
        try {
            // Instantiate Internet Explorer
            InternetExplorer ie = new InternetExplorer();  

            // Get IWebBrowserApp  
            app = ie.getIWebBrowserApp();  

            // HINT:  While developing, make the browser visible!! 
            //   app.setVisible( true );  
            // NOTE: When browser is not visible, the following workaround must
            // be added for an Internet Explorer bug 
            // (http://support.microsoft.com/kb/259935)
            // Remove it or comment it out if setting the browser visible.
            app.setLeft( - app.getWidth());

            // If IE is trying to load any default pages, stop it.  
            app.Stop();  

            // Attach the events listener.
            webLoadListener = new WebLoadListener();
            ie.addJComEventListener( webLoadListener );

            // Setup a JTree in the JFrame, along with a pane for entering URLs

            getContentPane().setLayout( new BorderLayout());
            JPanel panel = new JPanel( new GridLayout(1,0));
            panel.add( tree );
            JScrollPane scrollView = new JScrollPane( panel );
            getContentPane().add( scrollView, BorderLayout.CENTER );
            JButton button = new JButton();
            JLabel label = new JLabel( "URL: " );;
            JPanel buttonPanel = new JPanel();

            button.setText( "Navigate" );
            buttonPanel.add( label );
            buttonPanel.add( url );
            buttonPanel.add( button );
            getContentPane().add( buttonPanel, BorderLayout.SOUTH );
            button.addActionListener( new ActionListener() {
                public void actionPerformed( ActionEvent e ) { onButtonClick(); }
            });


            // Center in frame, set visible
            setSize( FRAME_WIDTH, FRAME_HEIGHT );
            Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
            setLocation(( screenSize.width - FRAME_WIDTH ) / 2,
                        ( screenSize.height - FRAME_HEIGHT ) / 2 );
            setVisible(true);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    // Walk the nodes of the HTML tree structure recursively,
    // adding to the JTree.
    void recursiveWalk( IHTMLElement element, DefaultMutableTreeNode node )
    {
        try {
            JComObject obj = element.getChildren();
            boolean leafNode = true;
            if ( obj != null ) {
                IHTMLElementCollection children = (IHTMLElementCollection)
                    element.getChildren().JComCoerceObjectToAnotherType( IHTMLElementCollection.class );
                // Process all the children.
                if ( children != null && children.getLength() > 0 ) {
                    for ( int i = 0; i < children.getLength(); i++ ) {
                        IHTMLElement child = (IHTMLElement) children.item(
                              new JComVariant( i )).JComCoerceObjectToAnotherType( IHTMLElement.class );
                        DefaultMutableTreeNode newNode = new DefaultMutableTreeNode( child.getTagName());
                        node.add( newNode );
                        recursiveWalk( child, newNode );
                    }
                    leafNode = false; // Node has children
                }
            }

            // Make some guesses to see if it is a textual node.
            String tag = element.getTagName();
            if ( tag != null &&
                ( tag.equalsIgnoreCase( "P" ) || tag.equalsIgnoreCase( "LI" ))) {
                // Add text for paragraph nodes.
                DefaultMutableTreeNode newNode =
                    new DefaultMutableTreeNode( element.getInnerText());
                node.add( newNode );
            } else if ( leafNode ) {
                // Leaf node, add HTML as a child node.
                DefaultMutableTreeNode newNode =
                    new DefaultMutableTreeNode( element.getOuterHTML());
                node.add( newNode );
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    // Start point of the recursive tree walk
    void htmlTreeWalk()
    {  
        try {  
            // Now retrieve and examine the contents of the website.
            IHTMLDocument3 doc3 = (IHTMLDocument3)
                 app.getDocument().JComCoerceObjectToAnotherType( IHTMLDocument3.class );

            // Get the document root element
            IHTMLElement docElement = (IHTMLElement)
                doc3.getDocumentElement().JComCoerceObjectToAnotherType( IHTMLElement.class );
            // Walk the root element, adding leafs to the tree
            DefaultMutableTreeNode node =
                new DefaultMutableTreeNode( docElement.getTagName());
            root.removeAllChildren();
            root.add( node );
            recursiveWalk( docElement, node );
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    // Standard mechanism for initializing GUI with thread safety.
    private static void createAndShowGUI()
    {
        try {
            // Create and initialize a TreeWalk frame

            TreeWalk frame = new TreeWalk("HTML DOM Tree Walk");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            frame.initialize();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}