CIS 636 Spring 2003 Assignment 6 – Simple Threads in Java 100 points

Assigned: 03/17/2003

Due: 03/24/2003 at the start of class

You may work individually or in pairs for this assignment. But all work must be the work of the person/people whose name is on the code! If working in pairs, the individual contributions should be relatively equal. One possibility is to work together tonight, then finish separately (to avoid communication difficulties).

Main Assignment:

We are going to use related but unsynchronized threads to work in (sort of) parallel on a problem. The task is part of a computer-grading application for multiple choice tests. The task will be divided up among threads so that each thread works on a particular student’s test paper (A TestPaper class is provided – and is available on my WWW page under assignments). Each thread will calculate the score for the test paper that it is responsible for. The thread code will need to call code from the TestPaper class; for instance, the TestPaper class provides a method that does a lot of work for grading a test paper, and access methods that will enable storing the number correct, incorrect, and pct correct on the test for the test paper. You task is to 1) write a class that provides thread capabilities for this task. The class should include an instance variable to hold a TestPaper that the thread is to work on. You may set up your threads either extending Thread or implementing Runnable. 2) write main that a) kludges up the contents of the correct answers array, and kludges together an array of test papers to run the threads on (let my student constructor generate the student’s answers (saves you work)); b) starts a thread for each test paper; c) retrieves the results from each thread, and d) produces final summary results.

Once all of the threads have run (make sure all are done!), calculate the high score, low score, and mean score, and how many students were above the mean. Make sure your code will work even with “unlucky” timing.

Hand in:

• Disk with an entire folder containing all your relevant files (including the corresponding Byte-code files), in the appropriate folder structure for your package declarations and imports.
• Print out of your code.

Miscellaneous:

· MAKE YOUR WORK ROBUST!

· Make sure that your main demonstrates that your code works.

· Put YOUR NAME, and e-mail address in comments at the beginning of the program.

· Remember: Indentation, meaningful variable names, and meaningful comments. Weaknesses in any of these could result in points off. You MUST include comments that explain your program in order to get full credit.