CIS 636 Spring 2004 Assignment 6 – Simple Threads in Java 100 points

Assigned: 03/18/2004

Due: 03/25/2004 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 the correct folder structure, your files, any other of my classes that you use, and the corresponding Byte-code files. I should be able to get into the IDE and run your program without any messing with your files and folders. So test what you are handing in, even if you already tested it on a hard drive or wherever.
• Print out of your code. Make sure you change the print options in the IDE so that comments show up

To avoid needless long waits, I recommend working on this on the c: drive, then upon completion, copying it to the a: drive, testing it there, creating an extra backup for yourself, then (if working in lab) deleting it from the c: drive.

Miscellaneous:

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

· Put YOUR NAME, and e-mail address, date, AND where to mount filesystem in the IDE, in comments at the beginning of the program.

· Also, comment any significant code to document it (each method, each loop, each if, and each significant calculation should have a comment. In particular, each method needs to have a JAVADOC compatible comment).

· Indent code following standard conventions (indent to show that something is “inside” or “part of” the preceding code (e.g. inside if’s or loops, or statements continued on a new line). The IDE should handle this if you hit ENTER and move on to the next line (If you make changes, you may need to TAB to make things right).

· Name your variables meaningfully, to describe their use in the program.

Sample Interaction (I named all test papers John X to aid kludging setup, and didn’t name threads)

TestPaper: John 1 a d c a a b e d e c

TestPaper: John 2 a e c c d c e e d d

TestPaper: John 3 c c c e d e a b b b

TestPaper: John 4 e c a e d e e d d b

TestPaper: John 5 c a e c e c c d a e

TestPaper: John 6 d e c e e e a c c a

TestPaper: John 7 e a a c d c a b b d

TestPaper: John 8 e a c a e b c a e a

TestPaper: John 9 a c e e d b a b a d

TestPaper: John 10 b e b c b d e b d d

TestPaper: John 11 e d d a e a e a d e

TestPaper: John 12 b b b e a a b b a c

TestPaper: John 13 c a a e d c b e c c

TestPaper: John 14 d c e e c d b b d c

TestPaper: John 15 d a b d a d d d c d

Thread: Thread-1 pct: 0.2

Thread: Thread-2 pct: 0.2

Thread: Thread-3 pct: 0.2

Thread: Thread-4 pct: 0.0

Thread: Thread-5 pct: 0.4

Thread: Thread-6 pct: 0.2

Thread: Thread-7 pct: 0.1

Thread: Thread-8 pct: 0.3

Thread: Thread-9 pct: 0.3

Thread: Thread-10 pct: 0.2

Thread: Thread-11 pct: 0.2

Thread: Thread-12 pct: 0.3

Thread: Thread-13 pct: 0.0

Thread: Thread-14 pct: 0.2

Thread: Thread-15 pct: 0.2

Correct Answers:

a b c d e d c b a e

High Score: 0.4

Low Score: 0.0

Average: 0.20000000000000004

Number above mean: 4: