CIS3306 Project
Report
Design of a Java
Applet Computer Organization Problem Generator
John Phillips
bocaweb@hotmail.com
June 26, 2003
Executive Summary
A Java Applet was created for use in the CIS-3330 Computer Organization course
that I teach. Many students have problems with number conversions and terminology.
This program quizzes students with problems that are randomly generated. The
program is easily upgraded to other question types and topics by relying on
an abstract Problem class and the use of polymorphism.
The program can be launched in a new window by visiting the web page located
at http://www.programbetter.com/ts8802/project.html.
The project page for this program is located at http://www.programbetter.com/ts8802/index.html.
Introduction
I teach an online computer organization course each fall semester. Many of
the students seem to struggle with number conversion problems such as converting
a binary number into a decimal number. In addition, the students could benefit
by taking practice quizzes over terminology and other course topics.
The solution to this problem was to create an online program that would generate
random numeric practice problems as well as allow for terminology review and
other multiple choice and fill-in-the-blank type questions. The program was
coded as a Java Applet allowing easy access over the Internet by the students.
Another advantage of using an Applet is that updates can be made to the program
and the question set such that the students will always be using the latest
version.
The User Interface Design
I wanted to keep the user interface as simple as possible. A drop down selection
box is provided to allow the students to choose the type of problem they want
to practice. Clicking the 'New Problem' button displays a new question in
the question area on the screen. The student then types in an answer in the
answer text box and clicks the 'Check It' button. The program indicates whether
the students answer was correct. If not correct, the student can try to answer
it again as many times as is necessary. In addition, the student can click
on the 'Show Hint' button for a hint on how to solve this type of problem.
If the student still cannot get it then they can click the 'Show Answer' button
to see the correct answer. Clicking the 'New Problem' button will then generate
the next problem for the student to solve. Below is a screen shot of the student's
view of the applet.
The UML Design
Two UML documents were generated. The first is the overall class
diagram. The class diagram shows all of the classes used by the applet.
In addition, it show the relationships between the classes as well as the
attributes and behaviors that each class has. The second is a general activity
diagram. It shows a high-level view of the steps that occur as the applet
runs and as the user interacts with the applet.
The Code
As mentioned, the applet was coded using the Java programming language. The
focus of this project was to experiment with the latter ideas covered in the
CIS3306 course. The main program contains the GUI code and extends Java's JApplet
class. This program displays all of the buttons and text on the screen and
handles the events triggered when the buttons are clicked. When the 'New Problem'
button is clicked, the applet checks to see what type of problem is currently
selected in the problem type drop down box. It then creates a new myProb object
of that type and displays the question on the screen. The student can type
in their solution and click the 'Check It' button to have the solution checked
for correctness.
The interesting thing is that myProb is declared to be an object of the Problem
class yet it is instantiated as an object of the BinToDec class (or whatever
the selected problem type is). Throughout the rest of the applet the myProb
object is referred to as a Problem object and yet gets treated as a BinToDec
object. This polymorphism greatly simplifies adding new types of problems
to the applet as very few changes need to be made to the applet. In addition,
through inheritance, only a couple of methods need to be added to any new
type of problem class. Most of the methods that are needed are inherited from
the abstract Problem class.
The code is organized as follows:
project.html - code for the web
page that launches the applet
Project.java - code for the Applet
and GUI
Problem.java - code for the abstract
Problem class
The following are the polymorphic classes that inherit from Problem.java:
BinToDec.java - code for binary
to decimal conversions
DecToBin.java - code for decimal
to binary conversions
BinToOct.java - code for binary
to octal conversions
OctToBin.java - code for octal
to binary conversions
BinToHex.java - code for binary
to hexadecimal conversions
HexToBin.java - code for hexadecimal
to binary conversions
Terms.java - code for random terminology
questions
Conclusion
The program has only been tested on my home computer system running Windows
XP and using Internet Explorer 6. It seems to work quite well on this system.
However, this is the same operating system and browser my school is using
so I do not expect any major compatibility problems.
I would like to extend the program a bit more by redoing the Terms class.
I would like for it to retrieve problems either from a file or a database
located on the web server. Then adding new multiple choice questions about
terminology will be as simple as updating a text file with new questions and
answers. In addition, I would like to create at least two other problem types,
one for logical operators and one for 2's complement number conversions. I
would like each of these classes to generate random problems as well.
References
Deitel & Deitel (2003). Java How To Program, 5th ed. Prentice
Hall, NJ
Phillips, John (2003). Mansfield University CIS3306 project. http://www.programbetter.com/ts8802/.
June 26, 2003.
Schmuller, Joseph (1999). Sams Teach Yourself UML in 24 Hours. Sams,
IN
Sun Corporation (2003). Java 2 Platform Standard Edition v1.4.1 API.
Sun Corporation. http://java.sun.com/j2se/1.4.1/docs/api/.
June 26, 2003.
