Info for Info Course

Question

Sorry, if this post is not useful to you.
It will only be active for a week or so.
I accidently took this Java course. I thought it would be a more web page building type course. I never foresee myself ever using Java. I don't know why I can't program for shit. It sucks. I'm supposed to be smart but why can't I program?
Teacher says we can use java.sun.com for the practical portion of an exam. So I'm posting some useful code ( to me).
When I'm done, just let this forum die to the bottom of the list.
But in the meantime, if you need info on elementary Java stuff like GUI's, JDBC, Multithreading, etc., here it is.
Cheers

Answer 1

import javax.swing.*;
import java.awt.*;
// Generates the first application frame of the program.
public class CareerAdvisor
public static void main(String[] args)
     // Create application frame for User and Administrator JButton selections.
StartFrame f = new StartFrame();
f.setSize(350,300);
f.setLocation(340,210);
f.setVisible(true);
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
/* Loads the question panel and contains the buttons for the navigation
through the 5 question panels. */
public class CareerAdvisorFrame extends JFrame
     Connection con;
     Statement stmt;
     ResultSet rs;     
     // Accesses the previous question.
     JButton jbPrevious = new JButton("Previous");
     // The user clicks the 'Done' button when she has completed all questions.
     JButton jbDone = new JButton("Done");
     // Accesses the next question.
     JButton jbNext = new JButton("Next");
     int currentQuestion;
     /* There are 5 questions for the user to answer. Each question has its own
     question panel. */
     QuestionPanel[] qP = new QuestionPanel[5];
     /* The CareerAdvisorFrame GUI needs to be put into a container, which is
     activated.*/
     Container c = this.getContentPane();
     // The center panel contains the question.
     JPanel pCenter = new JPanel();
     // The south panel contains the 3 navigation buttons.
     JPanel pSouth = new JPanel();
     JFrame thisFrame;          
     String messageA = "";
     // GUI created.
     public CareerAdvisorFrame()
               thisFrame = this;
               currentQuestion = 1;
               // For each question, a question panel is generated.
               for (int i = 0; i<5; i++)
                    qP= new QuestionPanel(i+1);
               /* Specifying Border Layout for the container and the center panel. This
               is because     the question panel is created in its own class using the Grid
               Layout for the GUI construction. The south panel is constructed in this
               class and Grid Layout is used because 1 row of 3 columns is needed for
               the 3 navigation buttons. */
               c.setLayout(new BorderLayout());
               pCenter.setLayout(new BorderLayout());
               pSouth.setLayout(new GridLayout(1,3));
               // The 3 navigation buttons are added to the south panel.
               pSouth.add(jbPrevious);
               pSouth.add(jbDone);
               pSouth.add(jbNext);
               // The question panel is added to the center panel.
               pCenter.add(qP[0], BorderLayout.CENTER);
               // The south panel and center panels are added to the container.
               c.add(pSouth, BorderLayout.SOUTH);
               c.add(pCenter, BorderLayout.CENTER);
               /* To listen for mouse clicks on the 3 navigation buttons, action
               listeners must be added. Then, action handler parameters are passed. */
               ActionHandler actH = new ActionHandler();
               jbDone.addActionListener(actH);
               jbPrevious.addActionListener(actH);
               jbNext.addActionListener(actH);
     /* The location of the mouseclick is determined. Each of the 3 buttons have
     a specific function to accomplish and so methods are called. */
     public class ActionHandler implements ActionListener
          // The button source of the click is stored in ActionEvent e.
          public void actionPerformed(ActionEvent e)
               /* If the user clicks 'Next' the next() method is accessed. Different
               methods are accessed for the 'Previous' and 'Done' buttons. */
               if (e.getSource() == jbNext)
                    next();
               else if (e.getSource() == jbPrevious)
                    previous();
               else if (e.getSource() == jbDone)
                    done();
     /* The current question advances and the next question panel is put into the
     frame with the next question. When question 5 is reached, the 'Next' button
     is disabled because there are no further questions for the user to access.
     The button is enabled for the first 4 questions. The 'Previous' button is
     enabled at start up, even for the first question. This is to give a uniform
     appearance for the user when she first sees the Career Advisor Frame. The
     'Previous' button is also enabled if the current question does not equal 5.*/
     private void next()
          if (currentQuestion < 5)
               currentQuestion++;
               if (currentQuestion == 5)
                    jbNext.setEnabled(false);
                    // The panel is being refreshed with the new information.
                    pCenter.validate();
               else
                    jbPrevious.setEnabled(true);
                    pCenter.validate();
               // The current question is removed to add the next question.     
               pCenter.removeAll();
               pCenter.add(qP[currentQuestion - 1], BorderLayout.CENTER);
               pCenter.validate();
               // The next question is physically repainted onto the panel.
               repaint();
     /* After the current question decreases by one, the previous question panel
     is put into the frame with the previous question. When question 1 is
     reached, the 'Previous' button is disabled, since there is no question
     before the first one. The 'Next' button is enabled, when the current
     question is not equal to 1. */
     private void previous()
          if (currentQuestion > 1)
               currentQuestion--;
               if (currentQuestion == 1)
                    jbPrevious.setEnabled(false);
                    pCenter.validate();
               else
                    jbNext.setEnabled(true);
                    pCenter.validate();
               // The current question is removed to add the previous question.     
               pCenter.removeAll();
               pCenter.add(qP[currentQuestion - 1], BorderLayout.CENTER);
               pCenter.validate();
               repaint();
     /* The user's name is being stored in the Career database after the user
     provides it and then the career result is displayed. */
     private void done()
          // The 'Done' button is disabled after the user clicks it once
          jbDone.setEnabled(false);     
          String userName = "";
          /* The user enters his name in the input dialog. If he presses cancel, the
          program will exit. If he enters his name, he will be allowed to view his
          career result.*/
          do
               userName = JOptionPane.showInputDialog(
                    null,"Please enter your name:", "Career Result Access", 1);
               if (userName == null)
                    System.exit(0);
          }while (userName.equals(""));
     updateDataBase(userName);
ColoredJOptionPane c = new ColoredJOptionPane(new Color(255,236,139));
          c.showMessageDialog(null,message, "Career Result", 1);
          // The Career Advisor Frame dies after the user hits 'ok' on the dialog.     
          this.setVisible(false);                    
     // The user's answers and user's name are updated in the Career database.
     private void updateDataBase(String userName)
          String sourceURL = "jdbc:odbc:career";
          String query1 = "SELECT * FROM UserRecord";
          try
               /* The Microsoft Access Driver is loaded. The program is
                    connecting to the database. The stament object executes SQL
                    statements. */
     Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
     con = DriverManager.getConnection(sourceURL);
     stmt = con.createStatement(     ResultSet.TYPE_SCROLL_SENSITIVE,
                                                                                ResultSet.CONCUR_UPDATABLE);
     /* Querying the UserRecord table of the Career database and storing the
     statement in result set. */                                                                                     
                    rs = stmt.executeQuery(query1);
                    // The result set is moving to insert a row into the table.
                    rs.moveToInsertRow();
          /* Each column, 1-7, of the table is being updated with the user's name
          and each of his 5 answers to the questions. The 7th column is updated
          with the career title, messageA, that was outputted to the user in the
          dialog with the career result. The row is appended at the end of the
          table for these strings to be loaded into. */
          rs.updateString(1, userName);     
          rs.updateString(2, qP[0].getAnswer());
          rs.updateString(3, qP[1].getAnswer());
          rs.updateString(4, qP[2].getAnswer());
          rs.updateString(5, qP[3].getAnswer());
          rs.updateString(6, qP[4].getAnswer());          
          rs.updateString(7, messageA);     
          rs.insertRow();
          // The result set, statement, and database connection are closed.
     rs.close();
     stmt.close();
     con.close();                                                                                
          // Exceptions are declared.
          catch(SQLException sqle)
               System.err.println("Error creating connection");
     catch(ClassNotFoundException cnfe)
               System.err.println(cnfe.toString());
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
// A question panel is created. It connects to a database.
class QuestionPanel extends JPanel
     int questionNumber;
     String answer;
     int numberOfAnswers;
     // The background of the question panel is stored in SwimTiled.jpg.
     ImageIcon icon = new ImageIcon ("SwimTiled.jpg");
     JRadioButton[] rbAnswer = new JRadioButton[12];
     Connection con;
Statement stmt;
ResultSet rs;
/* The question panel reads each of 5 questions stored in the Career
database. There are 5 queries made for 5 tables, Q1 through Q5. Each question
has it's own table. */
public QuestionPanel(int qNum)
          questionNumber = qNum;
          /* Creating a button group allows only one radio button to be clicked per
          question. */
          ButtonGroup bg = new ButtonGroup();
          /* There are 14 rows created for the grid layout. One row is taken up by
          the question, one row for a blank space, and up to 12 rows for 12 radio
          button lines of text. The first question has the maximum number of radio
          buttons, named from 'a' to 'l'. The other questions require less than 12
          radio buttons.*/
          this.setLayout(new GridLayout(14,1));
          String sourceURL = "jdbc:odbc:career";
     String query1 = "SELECT * FROM Q1";
     String query2 = "SELECT * FROM Q2";
     String query3 = "SELECT * FROM Q3";
     String query4 = "SELECT * FROM Q4";
     String query5 = "SELECT * FROM Q5";
          try
          /* The Microsoft Access Driver is loaded. The program is
          connecting to the database. The stament object executes SQL
          statements. */
     Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
     con = DriverManager.getConnection(sourceURL);
     stmt = con.createStatement(     ResultSet.TYPE_SCROLL_SENSITIVE,
                                                                           ResultSet.CONCUR_UPDATABLE);
     /* When the qNum, or question number, equals 1, then Q1 is loaded into
     the result set as per query 1. This occurs for queries 2-5 as well.*/                    
          switch (qNum)
                    case 1:
                    rs = stmt.executeQuery(query1);break;
                    case 2:
                         rs = stmt.executeQuery(query2);break;
                    case 3:
                         rs = stmt.executeQuery(query3);break;
                    case 4:
                         rs = stmt.executeQuery(query4);break;
                    case 5:
                         rs = stmt.executeQuery(query5);break;
     // Exception handling
     catch(SQLException sqle)
          System.err.println("Error creating connection");
     catch(ClassNotFoundException cnfe)
          System.err.println(cnfe.toString());
     try
          // The result set proceeds to the next row.
          rs.next();
          /* The first part of the question, the non-radio button part is read
          from the 1st column of the corresponding question table in the
          database and put into a JLabel on the question panel. */
          this.add(new JLabel(rs.getString(1)));
          // This dummy JLabel creates a blank row in the question panel.
          this.add(new JLabel(""));
          // Action Handler created to handle actions on the radio buttons.
          ActionHandler actH = new ActionHandler();
          int k = 0;
          while(rs.next())
               /* The result set cycles through one of the question tables, Q1-Q5,
               and reads the radio button parts of the question into the button
               group and then the question panel until rs.next reveals no new data.
               These radio button parts are all in column 1 of the database table.
               An action listener with an action handling parameter is added to the
               rbAnswer array. */
               rbAnswer[k] = new JRadioButton(rs.getString(1));
               bg.add(rbAnswer[k]);
               this.add( rbAnswer[k]);
               rbAnswer[k].addActionListener(actH);
               /* The radio button array is kept visible to see the writing,
               despite the background. */
               rbAnswer[k].setOpaque( false );
               k++;
          numberOfAnswers = k;
     catch(SQLException sqle)
               System.err.println("Error in read next");
               /* Allows only some of the question panel to be painted with the
               background file, not the radio buttons in this case. */
               this.setOpaque( false );     
     // Returns one of the answers listed in the switch statement below.
     public String getAnswer()
          return answer;
     /* Listening for which radio button is clicked and getting the source of the
     radio button or answer that is clicked. The choice of radio buttons for a
     given question is between 1 and the amount stored in 'numberOfAnswers'.
     The switch statement assigns a particular radio button to a particular
     answer. */
     public class ActionHandler implements ActionListener
          public void actionPerformed(ActionEvent e)
               for (int i=0; i < numberOfAnswers; i++)
                    if (e.getSource() == rbAnswer[i])
                              switch (i)
                                   case 0: answer = "a"; break;
                                   case 1: answer = "b"; break;
                                   case 2: answer = "c"; break;
                                   case 3: answer = "d"; break;
                                   case 4: answer = "e"; break;
                                   case 5: answer = "f"; break;
                                   case 6: answer = "g"; break;
                                   case 7: answer = "h"; break;
                                   case 8: answer = "i"; break;
                                   case 9: answer = "j"; break;
                                   case 10: answer = "k"; break;
                                   case 11: answer = "l"; break;
     // Background image is being painted onto question panel.
     protected void paintComponent(Graphics g)
          // Scale image to size of component.
          Dimension d = getSize();
          g.drawImage(icon.getImage(), 0, 0, d.width, d.height, null);
          super.paintComponent(g);
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* StartFrame and StartFramePanel used to be one class upon initial design.
Separating them out allows the Panel to be painted with a background icon.
The container is created and made with border layout. The StartFramePanel
is put into the StartFrame. */
public class StartFrame extends JFrame
Container c = this.getContentPane();
public StartFrame()
          c.setLayout(new BorderLayout());
          StartFramePanel p = new StartFramePanel();
          // The StartFramePanel is centered in the container with a border layout.
          c.add(p, BorderLayout.CENTER);
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
// This class tracks the number of users and their individual data.
class AdminList extends JFrame
     Connection con;
Statement stmt;
ResultSet rs;
Container c = this.getContentPane();
     /* The information displayed in a frame that is used by the Administrator. The
     information is read from the UserRecord Table in the Career database. */
     public AdminList()
          /* There are 45 rows in the container with a grid layout so that at least
          43 new records can be added to the administrator list. The 1st row contains
          the titles of each column and the 2nd row is a blank line.*/
          c.setLayout(new GridLayout(45,1));
          String sourceURL = "jdbc:odbc:career";
     String query = "SELECT * FROM UserRecord";               
     /* The Microsoft Access Driver is loaded. The program is
connecting to the database. The stament object executes SQL
statements. */
          try
     Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
     con = DriverManager.getConnection(sourceURL);
     stmt = con.createStatement(     ResultSet.TYPE_SCROLL_SENSITIVE,
                                                                           ResultSet.CONCUR_UPDATABLE);
               rs = stmt.executeQuery(query);
     // Exception statements
     catch(SQLException sqle)
          System.err.println("Error creating connection");
     catch(ClassNotFoundException cnfe)
          System.err.println(cnfe.toString());
          // Adding titles to the 7 columns of the admin list.
          c.add(new JLabel("Name"));
          c.add(new JLabel("Question 1"));
          c.add(new JLabel("Question 2"));
          c.add(new JLabel("Question 3"));
          c.add(new JLabel("Question 4"));
          c.add(new JLabel("Question 5"));
          c.add(new JLabel("Advice"));
          // Create a blank row of 7 empty string columns.
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          try
          int count = 0;
          /* Each row of the UserName table is being read by the result set. The
          1-7 represent the columns being read from the database. */
          while(rs.next())
          count ++;
          c.add(new JLabel(rs.getString(1)));
          c.add(new JLabel(rs.getString(2)));
          c.add(new JLabel(rs.getString(3)));
          c.add(new JLabel(rs.getString(4)));
          c.add(new JLabel(rs.getString(5)));
          c.add(new JLabel(rs.getString(6)));
          c.add(new JLabel(rs.getString(7)));
     /* When the last row of data is reached, rs.next stops. For the
     remaining rows, the for loop uses the counter to add blank lines to the
     Admin List with dummy JLabels. */
     for (int i = count+1; i <= 43; i++)
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
          c.add(new JLabel(""));
     // Exception statements.
     catch(SQLException sqle)
               System.err.println("Error in read next");
import java.awt.*;
import javax.swing.*;
// Used to color dialog boxes in other classes.
class ColoredJOptionPane extends JOptionPane
public ColoredJOptionPane(){}
public ColoredJOptionPane(Color c)
     // Controls the color of the panel and option pane background in the dialog.
UIManager.put("OptionPane.background",c);
UIManager.put("Panel.background",c);
/* The following line would only be used if we wanted to change the color of
the buttons in the dialog. */
// UIManager.put("Button.background",c);
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* The start frame is the first frame that comes up for the user. Here, he can
select whether to use the Career Advisor program by clicking the 'User' button
or see the results of other users by clicking the 'Administrator' button.
This panel is put into the start frame. */
class StartFramePanel extends JPanel
     JButton jbUser = new JButton("User");
     JButton jbAdministrator = new JButton("Administrator");
     // This image is placed in the background of the 2 buttons.
     ImageIcon icon = new ImageIcon ("RoseTiled.jpg");     
     /* The frame for the StartFramePanel is created in the CareerAdvisorFrame
     class.*/
public StartFramePanel()
     /* Since there are only 2 JButtons, the rest of the spaces are made dummy
     labels. There are 5 rows of 3 columns in the grid layout. No container is
     used since a JPanel is used rather than a frame. */
     this.setLayout(new GridLayout(5,3));
          this.add(new JLabel());
          this.add(new JLabel());
          this.add(new JLabel());
          this.add(new JLabel());
          this.add(jbUser);
          this.add(new JLabel());
          this.add(new JLabel());
          this.add(new JLabel());
          this.add(new JLabel());
          this.add(new JLabel());
          this.add(jbAdministrator);
          this.add(new JLabel());
          this.add(new JLabel());
          this.add(new JLabel());
          this.add(new JLabel());
          /* Allows only some of the panel to be painted with the
          background file, not the JButtons in this case. */
          this.setOpaque( false );
          /* An ActionListener is being added to the 2 JButtons, with the action
          handler actH as a parameter being passed.     */
          ActionHandler actH = new ActionHandler();
          jbUser.addActionListener(actH);
          jbAdministrator.addActionListener(actH);
/* After getting the source of the JButton click event, it is determined
whether it is the jbUser or the jbAdministrator. In the former case,
the user() method is called and in the latter, the administrator()
method is called.*/
public class ActionHandler implements ActionListener
               public void actionPerformed(ActionEvent e)
                    if (e.getSource() == jbUser)
                    user();
                    else if (e.getSource() == jbAdministrator)
                    administrator();
          // This method enables the administrator to view the Admin List.
          private void administrator()
               // Initializing string
               String password = null;
               /* A default color of white is used in the dialog. This is denoted by
               the numbers 255,255,255. */
               ColoredJOptionPane c = new ColoredJOptionPane(new Color( 255,255,255));
          int count = 0;
          /* If after prompting the individual for the password 4 times, he
          doesn't get it right, then he is shown a message dialog and then
          exited out of the program. */
               do{
                         if (count>3)
                              JOptionPane.showMessageDialog(
                                   null, "You have been timed out.", "Incorrect Password", 1);
                              System.exit(0);
                         /* The administrator is prompted for the correct password
                         in an input dialog. The password is "dcba".*/
                         password =
                              JOptionPane.showInputDialog(null,"Password:", "Login Screen", 1);
                         // Allows the individual to click 'Cancel' in the dialog.                         
                    if (password == null)
                              return;
                         count++;
                    }while (!password.equals("dcba"));
               /* The AdminList Frame is created with specificed size and location,
               and then made visible. */
               AdminList f = new AdminList();
f.setSize(900,650);
f.setLocation(20,20);
     f.setVisible(true);
          /* This method allows the user to see the Welcome Message and take the
          Career Advisor questionaire. It has the same features of the
          administrator() method. */
          private void user()
               String password = null;
               ColoredJOptionPane c = new ColoredJOptionPane(new Color( 255,255,255));
               int count =0;
               do
                    if (count>3)
                         JOptionPane.showMessageDialog(
                              null, "You have been timed out.", "Incorrect Password", 1);
                         System.exit(0);
                    password =
                         JOptionPane.showInputDialog(null,"Password:", "Login Screen", 1);
                    if (password == null)
                         return;     
                    count ++;
               }while ( !password.equals("abcd") );
     String welcome = "Welcome ";
     // A sky blue color is the background of the dialog.
               ColoredJOptionPane d = new ColoredJOptionPane(new Color( 176,226,255));
               /* The string 'welcome' is put into a message dialog. The title on the
               dialog is 'Career Advising Service'. */
               JOptionPane.showMessageDialog
                    (null,welcome,"Career Advising Service", 1);
// The CareerAdvisor frame with the question panel is shown.
CareerAdvisorFrame frame = new CareerAdvisorFrame();
frame.setSize(850,400);
frame.setLocation(55,180);
frame.setVisible(true);
     // Background image is being painted onto the start panel.
     protected void paintComponent(Graphics g)
          // Scale image to size of component
          Dimension d = getSize();
          g.drawImage(icon.getImage(), 0, 0, d.width, d.height, null);
          super.paintComponent(g);