Plan for writing project2. When necessary you must fill in the parameters
for the methods. A methods here is refered to as  method() whether or not
it has parameters.

1. init()
number = JOptionPane.showInputDialog.

2. paint()
Calls process_all_lines()

3.  process_all_lines() 
In a loop extracts the substring, calculates IntNumber, from it, by
using Integer.parseInt() and adds that to sum.  Calls process_line().
Draws a line and then calls final_sum().

4. process_line() 
Calls print_line() and increments y.

5. print_line()
Calls process_digit() for each character in the substring.

6.  process_digit()
Using a case statement branching on a character calls drawBars()

7. drawBars()
Prtints the bar code digit.

8. final_sum()
Forms a string from the final sum integer and uses print_line()
to print it