Enlisting Java in the War Against SPAM: Training the Subject Line Screener

class Pop302d extends Frame{

  BufferedReader inputStream;
  PrintWriter outputStream;
  TextArea textArea = new TextArea(12,50);
  Button copyButton = new Button(
                           "Copy Selected Text");
  Button postButton = new Button("Post Text");
  Button deleteButton = new Button(
                            "Delete Local File");
  Button nextButton = new Button("Next");
  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 to process first message.",50);
  TreeSet subjWordList;
  String[] dirList;
  int fileCounter = 0;
  //Change the following to move to message files
  // to a different location on the disk.
  File dataDir = new File("c:/MailFiles");
  String msgToUser =
      "\nPost phrases for this message.\n" +
      "Then press Next to process next message.";

Listing 1

  public static void main(String[] args){
    Pop302d thisObj = new Pop302d();
    thisObj.makeSubjWordList();
  }//end main

Listing 2

  void makeSubjWordList(){
    subjWordList = new TreeSet();

    try{
      BufferedReader inData
        = new BufferedReader(new FileReader(
                                 "Pop302a.txt"));
      String data; //temp holding variable

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

      inData.close();//Close input file

Listing 3

      int N = 0;
      File theFile = null;
      for(N = 0;N < 6;N++){
        theFile = new File("Pop302a.bak" + N);
        if(!(theFile.exists()))break;
      }//end for loop

Listing 4

      if(N == 5){//del file 0 for use next time
        new File("Pop302a.bak0").delete();
      }//end if

Listing 5

      else{//delete the next file in sequence
        if(new File(
              "Pop302a.bak" + (N + 1)).exists()){
          new File(
               "Pop302a.bak" + (N + 1)).delete();
        }//end if
      }//end else

Listing 6

      DataOutputStream dataOut =
                          new DataOutputStream(
                            new FileOutputStream(
                                       theFile));

Listing 7

      Iterator iter = subjWordList.iterator();

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

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

Listing 8

  Pop302d(){//constructor
    this.addWindowListener(
      new WindowAdapter(){
        public void windowClosing(WindowEvent e){
          writeSubjWordList();
          System.exit(0);
        }//end windowClosing
      }//end WindowAdapter()
    );//end addWindowListener

Listing 9

    setLayout(new FlowLayout());

Listing 10

    nextButton.addActionListener(
      new ActionListener(){

Listing 11

        public void actionPerformed(
                                  ActionEvent e){

          if((fileCounter >= 0) &&
                 (fileCounter < dirList.length)){

Listing 12

            if(fileCounter ==
                           (dirList.length - 1)){
              writeSubjWordList();
              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 no more messages

Listing 13

            textArea.setText("Processing " +
                    dirList[fileCounter] + "\n");

            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.");

Listing 14

            try{
              BufferedReader inData
                        = new BufferedReader(
                        new FileReader(dataDir.
                        getAbsolutePath() + File.
                        separator + dirList[
                                  fileCounter]));

              String data; //temp holding area

              inData.mark(10000);

              subjField.setText(
                       "No Subj line found yet");
              fromField.setText(
                       "No From line found yet");

Listing 15

              while((data = inData.readLine())
                                        != null){

                data = removeStars(data);

                if(data.startsWith("Subject:")){
                  subjField.setText(
                             data.toUpperCase());
                  break;//No need to keep reading
                }//end if
              }//end while loop on null

Listing 16

              inData.reset();

              while((data = inData.readLine())
                                        != null){
                data = removeStars(data);

                if(data.startsWith("From:")){
                  fromField.setText(
                             data.toUpperCase());
                  break;
                }//end if
              }//end while loop on null

Listing 17

              inData.reset();

              while((data = inData.readLine())
                                        != null){
                data = removeStars(data);
                textArea.append(data + "\n");
              }//end while loop

Listing 18

              textArea.append(msgToUser + "\n");
              inData.close();//Close file
            }catch(Exception ex){
                           ex.printStackTrace();}

Listing 19

            fileCounter++;
          }//end if on fileCounter in bounds

Listing 20

          else{//file counter is out of bounds
            textArea.setText(
                 "No more files. Press Close to "
                 + "terminate.");
              nextButton.setEnabled(false);
          }//end else counter is out of bounds

        }//end actionPerformed
      }//end ActionListener
    );//end addActionListener

Listing 21

    ActionListener postListener =
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          String tempWord =
                       outputWordField.getText();
          subjWordList.add(tempWord);

          outputWordField.setText(
                           tempWord + " posted");
        }//end actionPerformed
      };//end ActionListener

Listing 22

      postButton.addActionListener(postListener);
      outputWordField.addActionListener(
                                   postListener);

Listing 23

    copyButton.addActionListener(
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          outputWordField.setText(
                    subjField.getSelectedText());
        }//end actionPerformed
      }//end new ActionListener
    );//end addActionListener

Listing 24

    deleteButton.addActionListener(
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          File tempFile = new File(
                      dataDir.getAbsolutePath() +
                      File.separator +
                      dirList[fileCounter-1]);
          if(tempFile.exists()){
            tempFile.delete();//Delete the file
          }//end if

Listing 25

          Toolkit.getDefaultToolkit().
          getSystemEventQueue().
          postEvent(new ActionEvent(
                              nextButton,
                              ActionEvent.
                                ACTION_PERFORMED,
                              "Next"));
        }//end actionPerformed
      }//end ActionListener
    );//end addActionListener

Listing 26

    add(copyButton);
    add(postButton);
    add(nextButton);
    add(deleteButton);
    add(fromField);
    add(subjField);
    add(outputWordField);
    add(operMsgField);
    add(textArea);
    setTitle("Copyright 2004, R.G.Baldwin");
    setSize(400,400);
    setVisible(true);

Listing 27

    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

Listing 28

    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

  }//end constructor
}//end class Pop302d

Listing 29

/*File Pop302d.java Copyright 2003, R.G.Baldwin
Rev 01/11/04

The purpose of this program is to process a text
file produced by P302.java for the purpose of
using the information contained in that file to
update the word list stored in Pop302a.txt

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

class Pop302d extends Frame{

  BufferedReader inputStream;
  PrintWriter outputStream;
  TextArea textArea = new TextArea(12,50);
  Button copyButton = new Button(
                           "Copy Selected Text");
  Button postButton = new Button("Post Text");
  Button deleteButton = new Button(
                            "Delete Local File");
  Button nextButton = new Button("Next");
  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 to process first message.",50);
  TreeSet subjWordList;
  String[] dirList;
  int fileCounter = 0;
  //Change the following to move to 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 to process next message.";

  public static void main(String[] args){
    Pop302d thisObj = new Pop302d();
    thisObj.makeSubjWordList();
  }//end main
  //===========================================//

  Pop302d(){//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.
          writeSubjWordList();
          System.exit(0);
        }//end windowClosing
      }//end WindowAdapter()
    );//end addWindowListener

    //Note, it will be necessary to temporarily
    // make this Pop302d GUI narrower to produce
    // the figures for publication.
    setLayout(new FlowLayout());

    //Register an ActionListener on the
    // nextButton.  This is an anonymous
    // class definition.
    nextButton.addActionListener(
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){

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

            if(fileCounter ==
                           (dirList.length - 1)){
              //The user clicked the Next button
              // but there are no more files.
              //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 later,
              // but this write operation is
              // provided here just in case the
              // user terminates without pressing
              // the close button.  The user can
              // post additional words to the
              // TreeSet object after this write
              // operation occurs.  That is why
              // an additional write operation
              // occurs when the user presses
              // the close button.
              writeSubjWordList();
              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 no more messages

            //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 data is displayed for
              // informtion purposes only to help
              // the user decide what to do in
              // terms of updating the word list
              // used by Pop302 for processing
              // the Subject line.
              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.");
              nextButton.setEnabled(false);
          }//end else counter is out of bounds
        }//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.
    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();
          subjWordList.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 ActionListener on the
    // copyButton to copy selected text to the
    // outputWordField
    copyButton.addActionListener(
      new ActionListener(){
        public void actionPerformed(
                                  ActionEvent e){
          outputWordField.setText(
                    subjField.getSelectedText());
        }//end actionPerformed
      }//end new 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.  Thus, they shouldn't be used
    // to construct spam-blocker word lists.
    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(copyButton);
    add(postButton);
    add(nextButton);
    add(deleteButton);
    add(fromField);
    add(subjField);
    add(outputWordField);
    add(operMsgField);
    add(textArea);
    setTitle("Copyright 2004, R.G.Baldwin");
    //Will need to make the GUI narrower in order
    // to create the figures for publication.
    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

  }//end constructor
  //===========================================//

  //Purpose:  To create a TreeSet object
  // containing words used to filter the message
  // subject lines in the program named
  // Pop302.java.
  //This method reads strings from a text file
  // named Pop302a.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
  // Pop302a.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 makeSubjWordList(){
    subjWordList = new TreeSet();

    //Read words or phrases from text file and
    // populate the TreeSet object.
    try{
      BufferedReader inData
        = new BufferedReader(new FileReader(
                                 "Pop302a.txt"));
      String data; //temp holding area

      while((data = inData.readLine()) != null){
        subjWordList.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("Pop302a.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("Pop302a.bak0").delete();
      }//end if
      else{//delete the next file in sequence
        if(new File(
              "Pop302a.bak" + (N + 1)).exists()){
          new File(
               "Pop302a.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 = subjWordList.iterator();

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

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

  //Purpose:  To write the data from a TreeSet
  // object into a file named Pop302a.txt that
  // is used in the program named Pop302.java to
  // filter the message subject lines.
  //This method is the reverse of the method
  // named makeSubjWordList.

  void writeSubjWordList(){
    try{
      DataOutputStream dataOut =
                          new DataOutputStream(
                            new FileOutputStream(
                                 "Pop302a.txt"));

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

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

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

  //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. Note that
  // all asterisks will be removed, not just
  // those inserted earlier.
  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 Pop302d
//============================================//

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