E-Voting Plan

After brainstorming (writing down single ideas), make some categories of features.  
Then organize the ideas into these categories.  Try to complete each category by adding
ideas that fit and augment the ideas that are already there. This takes the form of an outline.

== E-Voting ==

A.   Voting   (input)

1.   Show candidate names on [buttons]
2.   User presses a button
3.   Show the vote on the screen in a textField
4.   Allow corrections/changes ( [Reset Button] )
5.   Press [submit] button to finish ("cast vote")

B.   Saving   (storage)

1.   Count vote(s)
2.   At end of program, save total counts in a file

C.   Checking  (processing)

1.   Load list of voters
2.   Check voter-name - don't let them vote twice
3.   If they [submit] before voting, warn them and let them cancel

D.   Show Resuts (output)

1.   Check password so only a supervisor can see the votes
2.   Display totals in an output box, so they don't stay on screen  
3.   Print ballot on paper after [submit]

E.    Robustness  (error handling)

1.   Check user-id (password) before allowing voting
2.   Don't allow voting for more than one candidate
3.   Check admin-password before showing totals
4.   Don't allow same person to vote twice
5.   Don't allow program shut-down before [submit]
6.   Ensure saving totals before shut-down

Interface

A good plan also includes a user-interface design, for example:

This could be drawn with a pencil or using MS-Word, or by making
a simple prototype Java program.

How-To

We know we need to print paper ballots, save totals, load names of voters, and produce
and output box, but we need to find out how to program these in Java.  

== Output (and Input) ==

    javax.swing.JOptionPane.showMessageDialog(null,"You win!");

This displays "You win!" in a dialog box in the center of the screen.  If you had
an int variable named votes, you could display it with:

    javax.swing.JOptionPane.showMessageDialog(null,"" + votes);

Rather than always typing this very long command, you can encapsulate it in a method,
and then call that whenever you want to output some information.

    public static void output(String message)
    {
       javax.swing.JOptionPane.showMessageDialog(null, message );
    }

Now you can use the command   output("You win!");    to display some text.
So it's easy to put lots of output commands in your program.

Although it's not needed for the eVoting program, you might also want to know how-to
make and input box.

   public static String input(String message)
   {  
      return javax.swing.JOptionPane.showInputDialog(null, message);  
   }

You can use this to ask a question and input the answer, like this:

    String name = input("What is your name?");
    

== Saving in a File ==

Java has lots of different classes that can be used for file access.  They are all found in the java.io....
package.  The following uses a PrintWriter wrapped around a FileWriter to save text into a file.

   public static void save(String fileName, String message)
      throws java.io.IOException
   {
      java.io.PrintWriter file = 
            new java.io.PrintWriter(new java.io.FileWriter(fileName));

      file.println(message);

      file.close();
   }

The command file.println... is very similar to System.out.println - but instead of printing on the
screen, it prints into the file.  To print more text into the file, just add more file.println...
commands before closing the file.

== Loading from a File ==

   public static String load(String fileName)
       throws java.io.IOException
   {
      java.io.BufferedReader file = 
        new java.io.BufferedReader(new java.io.FileReader(fileName));

      String food = file.readLine();

      return food;
   }

This method opens a file and reads one line of text.  To read more lines of text,
you could add more file.readLine... commands, but you would need to put the
data into a bunch of different variables.  This would normally use a loop to do the
reading, and put the various lines of text into an array.

== Printing on Paper ==

Printing is a horrible, messy problem.  One of the big successes of Windows 3.0 was the fact
that Windows would take care of the messy problems of controlling printers.  The original
Java version 1 had NO features for printing - not even a sensible way of asking the operating
system to do the printing.  Later versions of Java have some printing features, but they are
messy to use.

The simplest solution is to write the information into a file (see save above), and then ask
another program to print it.  Notepad will print text files if you ask it nicely, like this:

  ...
     runProgram("notepad.exe /p c:\\food.txt");
  ...

This is a very simple and limited solution.  It only prints text-files, and automatically sends
the job to the default printer without asking any questions.  In a network, this is not always
the best solution.  And remember you must first save your text into the file food.txt,
before you can print it.  In the case of a voting program, this is a bit of a security issue,
as the voter probably doesn't want their name or vote saved in a file.

This also assumes the runProgram method below is available:

== Running Another Program ==

Even the best programmers cannot write every program they need.  All programmers share
and use the software written by other programmers.  This method runs a program -
the programName must tell the method where to find the program (complete path),
unless the program is in a common folder like the Windows OS folder.

  public static Process runProgram(String programName)
  {
      Process handle = null;
      try
      { 
         handle = Runtime.getRuntime().exec(programName);    
      }
      catch(java.io.IOException ex){ };

      return handle;
  }