CheckLinks To Use Spider

import java.awt.*;
import javax.swing.*;
import java.net.*;
import java.io.*;

/**
 * This example uses a Java spider to scan a Web site
 * and check for broken links. Written by Jeff Heaton.
 * Jeff Heaton is the author of "Programming Spiders,
 * Bots, and Aggregators" by Sybex. Jeff can be contacted
 * through his web site at http://www.jeffheaton.com.
 *
 * @author Jeff Heaton(http://www.jeffheaton.com)
 * @version 1.0
 */
public class CheckLinks extends javax.swing.JFrame implements Runnable,ISpiderReportable {

  /**
   * The constructor. Perform setup here.
   */
  public CheckLinks()
  {
    //{{INIT_CONTROLS
    setTitle("Find Broken Links");
    getContentPane().setLayout(null);
    setSize(405,288);
    setVisible(false);
    label1.setText("Enter a URL:");
    getContentPane().add(label1);
    label1.setBounds(12,12,84,12);
    begin.setText("Begin");
    begin.setActionCommand("Begin");
    getContentPane().add(begin);
    begin.setBounds(12,36,84,24);
    getContentPane().add(url);
    url.setBounds(108,36,288,24);
    errorScroll.setAutoscrolls(true);
    errorScroll.setHorizontalScrollBarPolicy(javax.swing.ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
    errorScroll.setVerticalScrollBarPolicy(javax.swing.ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
    errorScroll.setOpaque(true);
    getContentPane().add(errorScroll);
    errorScroll.setBounds(12,120,384,156);
    errors.setEditable(false);
    errorScroll.getViewport().add(errors);
    errors.setBounds(0,0,366,138);
    current.setText("Currently Processing: ");
    getContentPane().add(current);
    current.setBounds(12,72,384,12);
    goodLinksLabel.setText("Good Links: 0");
    getContentPane().add(goodLinksLabel);
    goodLinksLabel.setBounds(12,96,192,12);
    badLinksLabel.setText("Bad Links: 0");
    getContentPane().add(badLinksLabel);
    badLinksLabel.setBounds(216,96,96,12);
    //}}

    //{{INIT_MENUS
    //}}

    //{{REGISTER_LISTENERS
    SymAction lSymAction = new SymAction();
    begin.addActionListener(lSymAction);
    //}}
  }

  /**
   * Main method for the application.
   *
   * @param args Not used
   */
  static public void main(String args[])
  {
    (new CheckLinks()).setVisible(true);
  }

  /**
   * Add notifications.
   */
  public void addNotify()
  {
    // Record the size of the window prior to calling parents addNotify.
    Dimension size = getSize();

    super.addNotify();

    if ( frameSizeAdjusted )
      return;
    frameSizeAdjusted = true;

    // Adjust size of frame according to the insets and menu bar
    Insets insets = getInsets();
    javax.swing.JMenuBar menuBar = getRootPane().getJMenuBar();
    int menuBarHeight = 0;
    if ( menuBar != null )
      menuBarHeight = menuBar.getPreferredSize().height;
    setSize(insets.left + insets.right + size.width, insets.top + insets.bottom + size.height + menuBarHeight);
  }

  // Used by addNotify
  boolean frameSizeAdjusted = false;

  //{{DECLARE_CONTROLS
  javax.swing.JLabel label1 = new javax.swing.JLabel();

  /**
   * The begin or cancel button
   */
  javax.swing.JButton begin = new javax.swing.JButton();

  /**
   * The URL being processed.
   */
  javax.swing.JTextField url = new javax.swing.JTextField();

  /**
   * Scroll the errors.
   */
  javax.swing.JScrollPane errorScroll = new javax.swing.JScrollPane();

  /**
   * A place to store the errors created.
   */
  javax.swing.JTextArea errors = new javax.swing.JTextArea();
  javax.swing.JLabel current = new javax.swing.JLabel();
  javax.swing.JLabel goodLinksLabel = new javax.swing.JLabel();
  javax.swing.JLabel badLinksLabel = new javax.swing.JLabel();
  //}}

  //{{DECLARE_MENUS
  //}}

  /**
   * The background spider thread.
   */
  protected Thread backgroundThread;

  /**
   * The spider object being used.
   */
  protected Spider spider;

  /**
   * The URL that the spider begain with
   */
  protected URL base;

  /**
   * How many bad links have been found
   */
  protected int badLinksCount = 0;

  /**
   * How many good links have been found
   */
  protected int goodLinksCount = 0;

  /**
   * Internal class used to dispatch events.
   *
   * @author Jeff Heaton
   * @version 1.0
   */
  class SymAction implements java.awt.event.ActionListener {
    public void actionPerformed(java.awt.event.ActionEvent event)
    {
      Object object = event.getSource();
      if ( object == begin )
        begin_actionPerformed(event);
    }
  }

  /**
   * Called when the begin or cancel buttons are clicked.
   *
   * @param event The event associated with the button.
   */
  void begin_actionPerformed(java.awt.event.ActionEvent event)
  {
    if ( backgroundThread==null ) {
      begin.setLabel("Cancel");
      backgroundThread = new Thread(this);
      backgroundThread.start();
      goodLinksCount=0;
      badLinksCount=0;
    } else {
      spider.cancel();
    }

  }

  /**
   * Perform the background thread operation. This method
   * actually starts the background thread.
   */
  public void run()
  {
    try {
      errors.setText("");
      spider = new Spider(this);
      spider.clear();
      base = new URL(url.getText());
      spider.addURL(base);
      spider.begin();
      Runnable doLater = new Runnable()
      {
        public void run()
        {
          begin.setText("Begin");
        }
      };
      SwingUtilities.invokeLater(doLater);
      backgroundThread=null;

    } catch ( MalformedURLException e ) {
      UpdateErrors err = new UpdateErrors();
      err.msg = "Bad address.";
      SwingUtilities.invokeLater(err);         

    }
  }

  /**
   * Called by the spider when a URL is found. It is here
   * that links are validated.
   *
   * @param base The page that the link was found on.
   * @param url The actual link address.
   */
  public boolean spiderFoundURL(URL base,URL url)
  {
    UpdateCurrentStats cs = new UpdateCurrentStats();
    cs.msg = url.toString();
    SwingUtilities.invokeLater(cs);

    if ( !checkLink(url) ) {
      UpdateErrors err = new UpdateErrors();
      err.msg = url+"(on page " + base + ")/n";
      SwingUtilities.invokeLater(err);         
      badLinksCount++;
      return false;
    }

    goodLinksCount++;
    if ( !url.getHost().equalsIgnoreCase(base.getHost()) )
      return false;
    else
      return true;
  }

  /**
   * Called when a URL error is found.
   *
   * @param url The URL that resulted in an error.
   */
  public void spiderURLError(URL url)
  {
  }

  /**
   * Called internally to check if a link is good.
   *
   * @param url The link that is being checked.
   * @return True if the link was good, false otherwise.
   */
  protected boolean checkLink(URL url)
  {
    try {
      URLConnection connection = url.openConnection();
      connection.connect();        
      return true;
    } catch ( IOException e ) {
      return false;
    }
  }

  /**
   * Called when the spider finds an email address.
   *
   * @param email The email address the spider found.
   */
  public void spiderFoundEMail(String email)
  {
  }
  /**
   * Internal class used to update the error information
   * in a Thread-Safe way.
   *
   * @author Jeff Heaton
   * @version 1.0
   */

  class UpdateErrors implements Runnable {
    public String msg;
    public void run()
    {
      errors.append(msg);
    }
  }
  /**
   * Used to update the current status information
   * in a "Thread-Safe" way.
   *
   * @author Jeff Heaton
   * @version 1.0
   */

  class UpdateCurrentStats implements Runnable {
    public String msg;
    public void run()
    {
      current.setText("Currently Processing: " + msg );
      goodLinksLabel.setText("Good Links: " + goodLinksCount);
      badLinksLabel.setText("Bad Links: " + badLinksCount);
    }
  }

 

}