Enlisting Java in the War Against SPAM: Training the Body Screener

class Pop302e extends Frame{

  BufferedReader inputStream;
  PrintWriter outputStream;
  TextArea textArea = new TextArea(10,50);
  Button postButton = new Button("Post Word");
  Button deleteButton = new Button(
                    "Delete Local File/NextMsg");
  Button nextButton = new Button("Next Msg");
  Button selectIpButton = new Button(
                                    "Select IP");
  Button selectUrlButton = new Button(
                                   "Select URL");
  int prevUrl = 0;
  TextField fromField = new TextField(
                "From data will appear here",50);
  TextField subjField = new TextField(
             "Subject data will appear here",50);
  TextField outputWordField = new TextField(
             "User pastes output words here",50);
  TextField operMsgField = new TextField(
      "User instructions appear here. " +
      "Press Next Msg to process first message.",
                                             50);
  TreeSet bodyWordList;
  String[] dirList;
  int fileCounter = 0;
  //Change the following to move message files
  // to a more permanent location on the disk.
  File dataDir = new File("c:/MailFiles");
  String msgToUser =
           "\nPost phrases for this message.\n" +
           "Then press Next Msg to process " +
           "next message.";

Listing 1

  public static void main(String[] args){
    Pop302e thisObj = new Pop302e();
    thisObj.makeBodyWordList();
  }//end main

Listing 2

  Pop302e(){//constructor
    this.addWindowListener(
      new WindowAdapter(){
        public void windowClosing(WindowEvent e){
          writeBodyWordList();
          System.exit(0);
        }//end windowClosing
      }//end WindowAdapter()
    );//end addWindowListener

    setLayout(new FlowLayout());  

Listing 3

    //Register an ActionListener on the
    // nextButton.  This is an anonymous
    // class definition.
    nextButton.addActionListener(
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          //Do this to assist the action listener
          // on the selectUrlButton
          prevUrl = 0;

          //Protect against ArrayIndexOutOfBounds
          if((fileCounter >= 0) &&
                 (fileCounter < dirList.length)){

            //The user clicked the Next button
            // but there are no more files.
            if(fileCounter ==
                           (dirList.length - 1)){

              //Write the modified word list
              // stored in the TreeSet object to
              // an output file.  This also
              // happens when the user clicks the
              // close button on the Frame.
              writeBodyWordList();
              msgToUser = "\n\nNo more messages."
                  + "\nPost phrases for this "
                  + "message.\n Then press "
                  + "close to terminate.";
              //Disable the Next button so that
              // the user cannot fire any more
              // events of this type.
              nextButton.setEnabled(false);
            }//end if

            //Identify the file being processed
            textArea.setText("Processing " +
                    dirList[fileCounter] + "\n");

            //Provide instructions to the user.
            operMsgField.setText("Paste a phrase"
              + " in the output field and press "
              + "Post. Post as many new phrases "
              + "as you want. Press next to "
              + "process next message.");
            outputWordField.setText("Paste "
              + "output phrase here and then "
              + "press Post.");

            try{
              //Open the file containing a local
              // copy of the message.  Note that
              // the message has been mangled by
              // inserting asterisks in an
              // attempt to protect against
              // viruses.
              BufferedReader inData
                        = new BufferedReader(
                        new FileReader(dataDir.
                        getAbsolutePath() + File.
                        separator + dirList[
                                  fileCounter]));
              String data; //temp holding area

              //Precondition the display of
              // Subject in the GUI by skipping
              // header lines prior to the
              // Subject line. Mark the beginning
              // of the file.  Set the
              // readAheadLimit to 10000
              // characters before the mark will
              // be lost.
              inData.mark(10000);
              //Some messages may not contain a
              // Subject or From line.  Don't
              // want the old one to continue to
              // be visible in the GUI.
              subjField.setText(
                       "No Subj line found yet");
              fromField.setText(
                       "No From line found yet");
              while((data = inData.readLine())
                                        != null){
                //A null result indicates end of
                // file.

                //Remove the asterisks that were
                // inserted into the data when
                // the file was written in an
                // attempt to protect against
                // viruses.  Append two asterisks
                // to the end of each line.
                data = removeStars(data);

                //Trap the Subject line, convert
                // it to upper case, and display
                // it in a field on the GUI.
                if(data.startsWith("Subject:")){
                  subjField.setText(
                             data.toUpperCase());
                  break;//No need to keep reading
                }//end if
              }//end while loop on null

              //Reset back to beginning of file.
              // The Subject for this message is
              // now showing in the GUI.
              inData.reset();

              //Precondition the display of From
              // line in the GUI by skipping
              // header lines prior to the From
              // line.  Code is similar to that
              // discssed above.
              while((data = inData.readLine())
                                        != null){
                data = removeStars(data);
                if(data.startsWith("From:")){
                  fromField.setText(
                             data.toUpperCase());
                  break;
                }//end if
              }//end while loop on null

              //Reset back to beginning of file.
              // The From line for this message
              // is now showing  in the GUI. Read
              // and display the entire file.
              // This is the data that the user
              // will analyze to determine the
              // new words or phrases that will
              // be added to the word list.
              inData.reset();

              //Read and display strings until
              // eof is indicated by null.
              while((data = inData.readLine())
                                        != null){
                data = removeStars(data);
                textArea.append(data + "\n");
              }//end while loop

              //Display messages to the user at
              // the end of the data in the text
              // area.
              textArea.append(msgToUser + "\n");
              inData.close();//Close file
            }catch(Exception ex){
                           ex.printStackTrace();}

            //Increment the fileCounter so that
            // the next time the Next button
            // fires an ActionEvent, the next
            // file in the directory listing will
            // be processed.
            fileCounter++;

          }//end if on fileCounter in bounds
          else{
            //File counter out of bounds.  This
            // happens if you delete all the
            // files.
            textArea.setText(
                 "No more files. Press Close to "
                 + "terminate.");
          }//end else
        }//end actionPerformed
      }//end ActionListener
    );//end addActionListener

Listing 4

    ActionListener postListener =
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          //Get the word or phrase from the field
          // and add it to the TreeSet object.
          String tempWord =
                       outputWordField.getText();
          bodyWordList.add(tempWord);

          //Provide feedback to confirm that it
          // has been posted.  This tells the
          // user that she is free to post
          // another word if she desires.
          outputWordField.setText(
                           tempWord + " posted");
        }//end actionPerformed
      };//end ActionListener

      //Register the ActionListener object on
      // the two source objects.
      postButton.addActionListener(postListener);
      outputWordField.addActionListener(
                                   postListener);

Listing 5

...
Received: from mailhub1.austin.cc.tx.us 
(root@mailhub1.austin.cc.tx.us [206.77.151.36])
	by omnistarhost.com (8.11.6/8.11.6) 
with ESMTP id i0QFxtc12960
	for <Baldwin@DickBaldwin.com>; 
Mon, 26 Jan 2004 09:59:55 -0600
Received: from monk.austincc.edu 
(root@monk.austin.cc.tx.us [198.213.3.10])
	by mailhub1.austin.cc.tx.us 
(8.12.3/8.12.3/Debian-6.4) with ESMTP id 
i0QFtIxS028428;
	Mon, 26 Jan 2004 09:55:18 -0600
Received: from D3093X31 (m198214191169.
austin.cc.tx.us [198.214.191.169])
	by monk.austincc.edu 
(8.12.3/8.12.3/Debian -4) with SMTP id 
i0QFt8De001872;
	Mon, 26 Jan 2004 09:55:08 -0600
Message-ID: <000a01c3e425$60bc1e50$a9bfd6c6@
D3093X31>

Figure 4

Search results for: 198.214.191.169  
          
Univ. of Texas System Office of Telecom. 
Services NETBLK-THENET-CIDR-C2
(NET-198-214-0-0-1) 
198.214.0.0 - 198.214.255.255
Austin Community College AUS-COM-COL2 
(NET-198-214-176-0-1)
198.214.176.0 - 198.214.191.255

# ARIN WHOIS database, last updated 
2004-01-26 19:15

Figure 5

OrgName:    Austin Community College
OrgID:      ACC-9
Address:    Riverside Campus
Address:    1020 Grove Blvd.
City:       Austin
StateProv:  TX
PostalCode: 78741
Country:    US

NetRange:   198.214.176.0 - 198.214.191.255
CIDR:       198.214.176.0/20
NetName:    AUS-COM-COL2
NetHandle:  NET-198-214-176-0-1
Parent:     NET-198-214-0-0-1
NetType:    Reassigned
Comment:
RegDate:    1995-02-23
Updated:    1995-02-23

TechHandle: GK87-ARIN
TechName:   --Name removed by Baldwin--
TechPhone:  --Phone number removed by Baldwin--
TechEmail:  --Email address removed by Baldwin--

Figure 6

      selectIpButton.addActionListener(
        new ActionListener(){
          public void actionPerformed(
                                  ActionEvent e){
            //Create a String replica of the
            // contents of the textArea.
            String theString =
                              textArea.getText();
            //Get the index of the line
            // containing the originating
            // IP address.
            int receivedIndex =
              theString.lastIndexOf("Received:");
            //Scroll to make that line visible
            // in the text area.
            textArea.select(
                  receivedIndex,receivedIndex+9);
            //Get the indices of the square
            // brackets containing the IP address
            int leftIpIndex = theString.indexOf(
                              '[',receivedIndex);
            if(leftIpIndex != -1){
              int rightIpIndex =
                               theString.indexOf(
                                ']',leftIpIndex);
              //Select the IP address and write
              // it into the outputWordField.
              textArea.select(leftIpIndex+1,
                                   rightIpIndex);
              outputWordField.setText(
                     textArea.getSelectedText());
            }//end if not -1
            else{//leftIpIndex == -1
              outputWordField.setText(
               "No [...] on this Received line");
            }//end else
          }//end actionPerformed
        }//end ActionListener
      );//end addActionListener

Listing 6

      selectUrlButton.addActionListener(
        new ActionListener(){
          public void actionPerformed(
                                  ActionEvent e){
            //Create an upper-case String
            // replica of the contents of the
            // textArea, and convert the contents
            // of the text area to upper case.
            String theString =
                textArea.getText().toUpperCase();
            textArea.setText(theString);

            //Get the index of the next URL and
            // save it as previous URL for
            // initialization purposes.
            int urlIndex =
              theString.indexOf(
                              "HTTP://",prevUrl);
              prevUrl = urlIndex + 1;

            //Get the index of the first / in the
            // URL following the //.  Also deal
            // with the possibility that no URL
            // was found.  This slash character
            // signals the end of the server name
            // and the beginning of a directory
            // on the server.  Don't include the
            // directory name in the selected
            // text.
            if(urlIndex != -1){
              //A URL was found.
              int slashIndex = theString.indexOf(
                               '/',urlIndex + 7);
              //Deal with the possibility that
              // the URL doesn't contain a slash
              // in the body of the URL and
              // there is no slash later in the
              // message.
              if(slashIndex != -1){
                //Deal with URLs that don't have
                // a slash in them causing the
                // program to find the next slash
                // somewhere in the body of the
                // text instead. Limit the amount
                // of selected text to 80 
                // characters.  The extra text
                // will require editing in the
                // text field by the user.
                if(slashIndex - urlIndex > 80){
                  slashIndex = urlIndex + 80;
                }//end if
                //Select the URL, beginning after
                // the second slash, and write it
                // into the outputWordField.
                //Discard HTTP:// to reduce run
                // time later when screening
                // for SPAM messages on the
                // server.
                textArea.select(
                          urlIndex+7,slashIndex);
                //Put the selected URL into the
                // output word field.
                outputWordField.setText(
                     textArea.getSelectedText());
              }//if slashIndex != -1
              else{
                //Program doesn't handle this
                // unusual situation.
                outputWordField.setText("Can't "
                   + "find / following HTTP://");
              }//end else
            }//end if urlIndex != -1
            else{//urlIndex == -1
              outputWordField.setText(
                           "Can't find HTTP://");
            }//end else
          }//end actionPerformed
        }//end ActionListener
      );//end addActionListener

Listing 7

    deleteButton.addActionListener(
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          //Delete the local file currently being
          // displayed in the GUI. Must subtract
          // one from the value of the file
          // counter to cause it to reference the
          // current file because it has already
          // been incremented by the event
          // handler for the Next button in
          // preparation for processing the next
          // file.

          //Create a File object that represents
          // the current file.
          File tempFile = new File(
                      dataDir.getAbsolutePath() +
                      File.separator +
                      dirList[fileCounter-1]);
          if(tempFile.exists()){
            tempFile.delete();//Delete the file
          }//end if

          //Fire a synthetic event on the Next
          // button to cause the program to
          // process the next file in the
          // directory listing.
          Toolkit.getDefaultToolkit().
          getSystemEventQueue().
          postEvent(new ActionEvent(
                              nextButton,
                              ActionEvent.
                                ACTION_PERFORMED,
                              "Next"));
        }//end actionPerformed
      }//end ActionListener
    );//end addActionListener

Listing 8

    add(postButton);
    add(nextButton);
    add(deleteButton);
    add(selectIpButton);
    add(selectUrlButton);
    add(fromField);
    add(subjField);
    add(outputWordField);
    add(operMsgField);
    add(textArea);
    setTitle("Copyright 2004, R.G.Baldwin");
    //You should increase the width to at least
    // 750 pixels, and increase the width of the
    // text fields and the text area to at least
    // 100 characters to make the GUI more
    // usable.
    setSize(400,400);
    //Make the GUI visible.
    setVisible(true);

Listing 9

/*File Pop302e.java Copyright 2004, R.G.Baldwin
Rev 01/26/05

The purpose of this program is to process text
files produced by P302.java for the purpose of
using the information contained in those files to
update the word list stored in Pop302b.txt

Tested using SDK 1.4.2 under WinXP
************************************************/
import java.io.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;

class Pop302e extends Frame{

  BufferedReader inputStream;
  PrintWriter outputStream;
  TextArea textArea = new TextArea(10,50);
  Button postButton = new Button("Post Word");
  Button deleteButton = new Button(
                    "Delete Local File/NextMsg");
  Button nextButton = new Button("Next Msg");
  Button selectIpButton = new Button(
                                    "Select IP");
  Button selectUrlButton = new Button(
                                   "Select URL");
  int prevUrl = 0;
  TextField fromField = new TextField(
                "From data will appear here",50);
  TextField subjField = new TextField(
             "Subject data will appear here",50);
  TextField outputWordField = new TextField(
             "User pastes output words here",50);
  TextField operMsgField = new TextField(
      "User instructions appear here. " +
      "Press Next Msg to process first message.",
                                             50);
  TreeSet bodyWordList;
  String[] dirList;
  int fileCounter = 0;
  //Change the following to move message files
  // to a more permanent location on the disk.
  File dataDir = new File("c:/MailFiles");
  String msgToUser =
           "\nPost phrases for this message.\n" +
           "Then press Next Msg to process " +
           "next message.";

  public static void main(String[] args){
    Pop302e thisObj = new Pop302e();
    thisObj.makeBodyWordList();
  }//end main
  //===========================================//

  Pop302e(){//constructor
    //Register a window listener to service
    // the close button on the Frame.  This is
    // an anonymous class defiition.
    this.addWindowListener(
      new WindowAdapter(){
        public void windowClosing(WindowEvent e){
          //Write the updated word list stored in
          // a TreeSet object to an output file
          // on shutdown.  It is also written
          // when you click the Next button and
          // there are no remaining files to be
          // processed.
          writeBodyWordList();
          System.exit(0);
        }//end windowClosing
      }//end WindowAdapter()
    );//end addWindowListener

    setLayout(new FlowLayout());

    //Register an ActionListener on the
    // nextButton.  This is an anonymous
    // class definition.
    nextButton.addActionListener(
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          //Do this to assist the action listener
          // on the selectUrlButton
          prevUrl = 0;

          //Protect against ArrayIndexOutOfBounds
          if((fileCounter >= 0) &&
                 (fileCounter < dirList.length)){

            //The user clicked the Next button
            // but there are no more files.
            if(fileCounter ==
                           (dirList.length - 1)){

              //Write the modified word list
              // stored in the TreeSet object to
              // an output file.  This also
              // happens when the user clicks the
              // close button on the Frame.
              writeBodyWordList();
              msgToUser = "\n\nNo more messages."
                  + "\nPost phrases for this "
                  + "message.\n Then press "
                  + "close to terminate.";
              //Disable the Next button so that
              // the user cannot fire any more
              // events of this type.
              nextButton.setEnabled(false);
            }//end if

            //Identify the file being processed
            textArea.setText("Processing " +
                    dirList[fileCounter] + "\n");

            //Provide instructions to the user.
            operMsgField.setText("Paste a phrase"
              + " in the output field and press "
              + "Post. Post as many new phrases "
              + "as you want. Press next to "
              + "process next message.");
            outputWordField.setText("Paste "
              + "output phrase here and then "
              + "press Post.");

            try{
              //Open the file containing a local
              // copy of the message.  Note that
              // the message has been mangled by
              // inserting asterisks in an
              // attempt to protect against
              // viruses.
              BufferedReader inData
                        = new BufferedReader(
                        new FileReader(dataDir.
                        getAbsolutePath() + File.
                        separator + dirList[
                                  fileCounter]));
              String data; //temp holding area

              //Precondition the display of
              // Subject in the GUI by skipping
              // header lines prior to the
              // Subject line. Mark the beginning
              // of the file.  Set the
              // readAheadLimit to 10000
              // characters before the mark will
              // be lost.
              inData.mark(10000);
              //Some messages may not contain a
              // Subject or From line.  Don't
              // want the old one to continue to
              // be visible in the GUI.
              subjField.setText(
                       "No Subj line found yet");
              fromField.setText(
                       "No From line found yet");
              while((data = inData.readLine())
                                        != null){
                //A null result indicates end of
                // file.

                //Remove the asterisks that were
                // inserted into the data when
                // the file was written in an
                // attempt to protect against
                // viruses.  Append two asterisks
                // to the end of each line.
                data = removeStars(data);

                //Trap the Subject line, convert
                // it to upper case, and display
                // it in a field on the GUI.
                if(data.startsWith("Subject:")){
                  subjField.setText(
                             data.toUpperCase());
                  break;//No need to keep reading
                }//end if
              }//end while loop on null

              //Reset back to beginning of file.
              // The Subject for this message is
              // now showing in the GUI.
              inData.reset();

              //Precondition the display of From
              // line in the GUI by skipping
              // header lines prior to the From
              // line.  Code is similar to that
              // discssed above.
              while((data = inData.readLine())
                                        != null){
                data = removeStars(data);
                if(data.startsWith("From:")){
                  fromField.setText(
                             data.toUpperCase());
                  break;
                }//end if
              }//end while loop on null

              //Reset back to beginning of file.
              // The From line for this message
              // is now showing  in the GUI. Read
              // and display the entire file.
              // This is the data that the user
              // will analyze to determine the
              // new words or phrases that will
              // be added to the word list.
              inData.reset();

              //Read and display strings until
              // eof is indicated by null.
              while((data = inData.readLine())
                                        != null){
                data = removeStars(data);
                textArea.append(data + "\n");
              }//end while loop

              //Display messages to the user at
              // the end of the data in the text
              // area.
              textArea.append(msgToUser + "\n");
              inData.close();//Close file
            }catch(Exception ex){
                           ex.printStackTrace();}

            //Increment the fileCounter so that
            // the next time the Next button
            // fires an ActionEvent, the next
            // file in the directory listing will
            // be processed.
            fileCounter++;

          }//end if on fileCounter in bounds
          else{
            //File counter out of bounds.  This
            // happens if you delete all the
            // files.
            textArea.setText(
                 "No more files. Press Close to "
                 + "terminate.");
          }//end else
        }//end actionPerformed
      }//end ActionListener
    );//end addActionListener

    //Register an object of the following
    // anonymous class on both the Post button
    // and the outputWordField. That way, the
    // contents of the outputWordField can be
    // posted to the new word list by either
    // clicking the Post button, or pressing the
    // Enter key when the outputWordField has the
    // focus.  Note that this is an anonymous
    // class, but it is not an anonymous object.
    ActionListener postListener =
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          //Get the word or phrase from the field
          // and add it to the TreeSet object.
          String tempWord =
                       outputWordField.getText();
          bodyWordList.add(tempWord);

          //Provide feedback to confirm that it
          // has been posted.  This tells the
          // user that she is free to post
          // another word if she desires.
          outputWordField.setText(
                           tempWord + " posted");
        }//end actionPerformed
      };//end ActionListener

      //Register the ActionListener object on
      // the two source objects.
      postButton.addActionListener(postListener);
      outputWordField.addActionListener(
                                   postListener);

      //Register an action listener on the
      // selectIP button.  This listener finds
      // and selects the IP address of the
      // originator of the message.  Then it
      // writes the selected characters into the
      // outputWordField where it can be added
      // to the word list by pressing the Post
      // button.
      //The IP address of the originator is the
      // first IP address in square brackets that
      // occurs in the last line in the message
      // that starts with "Received:"
      selectIpButton.addActionListener(
        new ActionListener(){
          public void actionPerformed(
                                  ActionEvent e){
            //Create a String replica of the
            // contents of the textArea.
            String theString =
                              textArea.getText();
            //Get the index of the line
            // containing the originating
            // IP address.
            int receivedIndex =
              theString.lastIndexOf("Received:");
            //Make that line visible
            textArea.select(
                  receivedIndex,receivedIndex+9);
            //Get the indices of the square
            // brackets containing the IP address
            int leftIpIndex =theString.indexOf(
                              '[',receivedIndex);
            if(leftIpIndex != -1){
              int rightIpIndex =
                               theString.indexOf(
                                ']',leftIpIndex);
              //Select the IP address and write
              // it into the outputWordField.
              textArea.select(leftIpIndex+1,
                                   rightIpIndex);
              outputWordField.setText(
                     textArea.getSelectedText());
            }//end if not -1
            else{//leftIpIndex == -1
              outputWordField.setText(
               "No [...] on this Received line");
            }//end else
          }//end actionPerformed
        }//end ActionListener
      );//end addActionListener


      //Register an action listener on the
      // selectUrl button.  This listener finds
      // and selects the next URL that appear in
      // the message.  When it finds a URL, it
      // writes the selected characters into the
      // outputWordField where it can be added
      // to the word list by pressing the Post
      // button.
      //URLs are located by searching for HTTP://
      //A good upgrade would be to eliminate WWW
      // when it is included in the URL, because
      // it doesn't add much information and
      // consumes processing time later when
      // messages on the server are being
      // screened.
      selectUrlButton.addActionListener(
        new ActionListener(){
          public void actionPerformed(
                                  ActionEvent e){
            //Create an upper-case String
            // replica of the contents of the
            // textArea, and convert the contents
            // of the text area to upper case.
            String theString =
                textArea.getText().toUpperCase();
            textArea.setText(theString);

            //Get the index of the next URL and
            // save it as previous URL.
            int urlIndex =
              theString.indexOf(
                              "HTTP://",prevUrl);
              prevUrl = urlIndex + 1;

            //Get the index of the first / in the
            // URL.  Deal with the possibility
            // that no URL will be found.
            if(urlIndex != -1){
              int slashIndex =theString.indexOf(
                               '/',urlIndex + 7);
              //Deal with the possibility that
              // the URL doesn't contain a slash
              // in the body of the URL and
              // there is no slash later in the
              // message.
              if(slashIndex != -1){
                //Deal with URLs that don't have
                // a slash in them causing the
                // program to find the next slash
                // somewhere in the body of the
                // text instead.
                if(slashIndex - urlIndex > 80){
                  slashIndex = urlIndex + 80;
                }//end if
                //Select the URL, beginning after
                // the second slash, and write it
                // into the outputWordField.
                //Discard HTTP:// to reduce run
                // time later when screening
                // for SPAM messages on the
                // server.
                textArea.select(
                          urlIndex+7,slashIndex);
                //Put the selected URL into the
                // output word field.
                outputWordField.setText(
                     textArea.getSelectedText());
              }//if slashIndex != -1
              else{
                outputWordField.setText("Can't "
                   + "find / following HTTP://");
              }//end else
            }//end if urlIndex != -1
            else{//urlIndex == -1
              outputWordField.setText(
                           "Can't find HTTP://");
            }//end else
          }//end actionPerformed
        }//end ActionListener
      );//end addActionListener

    //Register an ActionListener on the Delete
    // button to make it possible for the
    // user to remove a file from the local
    // directory.  The user would typically
    // delete files that are recognized as not
    // being SPAM.  Also, the user would
    // delete files for which analysis is
    // complete.  When a file is deleted using
    // this button, the next file is
    // automatically loaded ready for processing.
    deleteButton.addActionListener(
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          //Delete the local file currently being
          // displayed in the GUI. Must subtract
          // one from the value of the file
          // counter to cause it to reference the
          // current file because it has already
          // been incremented by the event
          // handler for the Next button in
          // preparation for processing the next
          // file.

          //Create a File object that represents
          // the current file.
          File tempFile = new File(
                      dataDir.getAbsolutePath() +
                      File.separator +
                      dirList[fileCounter-1]);
          if(tempFile.exists()){
            tempFile.delete();//Delete the file
          }//end if

          //Fire a synthetic event on the Next
          // button to cause the program to
          // process the next file in the
          // directory listing.
          Toolkit.getDefaultToolkit().
          getSystemEventQueue().
          postEvent(new ActionEvent(
                              nextButton,
                              ActionEvent.
                                ACTION_PERFORMED,
                              "Next"));
        }//end actionPerformed
      }//end ActionListener
    );//end addActionListener

    //Configure the GUI by placing the various
    // components on it.
    add(postButton);
    add(nextButton);
    add(deleteButton);
    add(selectIpButton);
    add(selectUrlButton);
    add(fromField);
    add(subjField);
    add(outputWordField);
    add(operMsgField);
    add(textArea);
    setTitle("Copyright 2004, R.G.Baldwin");
    //You should increase the width to at least
    // 750 pixels, and increase the width of the
    // text fields and the text area to at least
    // 100 characters to make the GUI more
    // usable.
    setSize(400,400);
    //Make the GUI visible.
    setVisible(true);

    //The following code creates a directory
    // listing containing only those files that
    // end in .txt.
    //This is an anonymous implementation of a
    // class that implements FilenameFilter.
    dirList = dataDir.list(
      new FilenameFilter(){
        public boolean accept(
                           File dir,String name){
          if(!(new File(dir,name).isFile()))
                                    return false;
          return name.endsWith(".txt");
        }//end accept
      }//end FilenameFilter
    );//end list

    //Create a message in the text area at
    // startup showing the list of files in the
    // directory that are available for
    // processing.
    this.textArea.append("Files to be processed"
                                         + "\n");
    //Display the list of files
    for(int cnt = 0;cnt < dirList.length;cnt++){
      this.textArea.append(dirList[cnt] + "\n");
    }//end for loop
    //Scroll back to the top of the text area
    textArea.select(0,0);
  }//end constructor
  //===========================================//


  //Purpose:  To create a TreeSet object
  // containing words used to filter the message
  // body lines in the program named
  // Pop302.java.
  //This method reads strings from a text file
  // named Pop302b.txt and creates the list as
  // a TreeSet object sorted in natural order
  // with no duplicates.
  //After creating the list, it writes the data
  // from the list into a backup file named
  // Pop302b.bakN, where N is the value of the
  // next available file name in the directory.
  //A new backup file with a unique name is
  // created each time the program is run. Once
  // the number of backup files reaches 5, the
  // program automatically deletes the oldest
  // file before creating a new backup
  // file.  Thus the program automatically
  // maintains a sequence of five backup files
  // with extensions .bak0 through bak5 with one
  // number missing.  The age-order of the files
  // should be determined by the modificatin date
  // and not by the name of the file.
  //The data read from the file is converted to
  // upper case before being added to the TreeSet
  // object.

  void makeBodyWordList(){
    bodyWordList = new TreeSet();

    //Read words or phrases from text file and
    // populate the TreeSet object.
    try{
      BufferedReader inData
        = new BufferedReader(new FileReader(
                                 "Pop302b.txt"));
      String data; //temp holding area

      while((data = inData.readLine()) != null){
        bodyWordList.add(data.toUpperCase());
      }//end while loop

      inData.close();//Close input file

      //Write a backup file before making any
      // modifications to the data.

      //First determine the name of the next
      // backup file allowed in the directory.
      int N = 0;
      File theFile = null;
      for(N = 0;N < 6;N++){
        theFile = new File("Pop302b.bak" + N);
        if(!(theFile.exists()))break;
      }//end for loop

      //Cause N to rotate from 0 through 5
      if(N == 5){//del file 0 for use next time
        new File("Pop302b.bak0").delete();
      }//end if
      else{//delete the next file in sequence
        if(new File(
              "Pop302b.bak" + (N + 1)).exists()){
          new File(
               "Pop302b.bak" + (N + 1)).delete();
        }//end if
      }//end else

      //Now write the output file
      DataOutputStream dataOut =
                          new DataOutputStream(
                            new FileOutputStream(
                                       theFile));

      //Use an Iterator object to access the data
      // in the TreeSet object.
      Iterator iter = bodyWordList.iterator();

      while(iter.hasNext()){
        data = (String)iter.next();
        dataOut.writeBytes(data + "\n");
      }//end while

      dataOut.close();
    }catch(Exception e){e.printStackTrace();}
  }//end makeBodyWordList
  //===========================================//

  //Purpose:  To write the data from a TreeSet
  // object into a file named Pop302b.txt that
  // is used in the program named Pop302.java to
  // filter the message body lines.
  //This method is the reverse of the method
  // named makeBodyWordList.

  void writeBodyWordList(){
    try{
      DataOutputStream dataOut =
                          new DataOutputStream(
                            new FileOutputStream(
                                 "Pop302b.txt"));

      //Use an iterator to access the data in
      // the TreeSet object.
      Iterator iter = bodyWordList.iterator();
      String data;

      while(iter.hasNext()){
        data = (String)iter.next();
        dataOut.writeBytes(data + "\n");
      }//end while

      dataOut.close();
    }catch(Exception e){e.printStackTrace();}
  }//end writeBodyWordList
  //===========================================//

  //Purpose of this method is to remove the
  // asterisks inserted into the data by the
  // method named insertStars when the data files
  // were stored on the disk.  In addition to
  // removing asterisks, two asterisks are
  // appended to the end of each line.
  String removeStars(String stringIn){
    StringBuffer stringBuf =
                      new StringBuffer(stringIn);
    int index = 0;
    while(index > -1){
      index = stringBuf.lastIndexOf("*");
      if(index > -1){
        stringBuf.delete(index,index+1);
      }//end if
    }//end while
    stringBuf.append("**");
    return new String(stringBuf);
  }//end removeStars()

}//end class Pop302e
//============================================//

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