CS706 Fall 2009
Homework #2
Due: Tuesday, September 29.

You may work on this homework in groups.

1. Exercise 3-6

2. Exercise 3-9

3. Exercise 3-11

4. Exercise 3-7

   You must have three separate and different solutions for parts (a), (b), and (c).

   Note: For part (c):
   - you probably want to keep track of the number of waiting
     men and women.
   - once one man enters the bathroom, he can let other waiting
     men enter too; same for when a woman enters the bathroom.

   Test your solutions to parts (a), (b), and (c) by implementing them 
   as Java programs with multiple man/woman threads. 

   I created a template for you in file UnisexBathroom.java. Complete 
   this code by completing class BathroomController. You need to declare 
   any variables you need and complete methods manEnter, manExit,
   womanEnter, and womanExit.

   Java classes binarySemaphore and countingSemaphore are in the
   Modern Multithreading (MM) library on the website for the 
   textbook:

      http://cs.gmu.edu/~rcarver/ModernMultithreading/LangLibTools.htm 

   I recommend downloading the Java JAR version in ModernMultithreadingJavaJar.zip.

   Use operations V and P, but *not* VP. (There is no need to use VP.) 
 
   You should have counters "numMen" and "numWomen" in your program, which count
   the number of men and women, respectively, who have entered the bathroom.
   At the point where men actually enter the bathroom, add the check:

    if (numWomen>0) System.out.println("Error: concurrent access");

   This detects when men and women are both in the bathroom. Do 
   the same check with numMen when women enter the bathroom.
   Perhaps this will help you detect errors.

   After your program appears to be running correctly, use the RTDriver
   to run your program in reachability testing mode with deadlock detection on.

   Assuming that you are using the jar file:

     Windows: java -classpath .;ModernMultithreading.jar -Dmode=rt 
                   -DdeadlockDetection=on -DVPReduction=on RTDriver UnisexBathroom

     Unix:    java -classpath .:ModernMultithreading.jar -Dmode=rt 
                   -DdeadlockDetection=on -DVPReduction=on RTDriver UnisexBathroom

   (Here I am assuming the jar file is in the same directory as your 
    UnisexBathroom.java file.)

   If you are using the source code files instead:

     java -Dmode=rt -DdeadlockDetection=on -DVPReduction=on RTDriver UnisexBathroom
 
   (Here I am assuming the source code files are in the same directory as your 
   UnisexBathroom.java file.)

   You may want to comment out any calls to Thread.sleep() and any output statements 
   before you run in rt mode. The file RTDriver is in the library.

   Reachability testing will go a lot faster if you use the "symmetry reduction":

     Windows: java -classpath .;ModernMultithreading.jar -Dmode=rt 
                   -DdeadlockDetection=on -DVPReduction=on -DsymmetryReduction=on RTDriver UnisexBathroom

     Unix:    java -classpath .:ModernMultithreading.jar -Dmode=rt 
                   -DdeadlockDetection=on -DVPReduction=on -DsymmetryReduction=on RTDriver UnisexBathroom

   or if you are using the source code files instead of the jar file:

     java -Dmode=rt -DdeadlockDetection=on -DVPReduction=on -DsymmetryReduction=on RTDriver UnisexBathroom
  
   Make sure you create the symmetry.txt file as explained in UserManual.pdf. For example, 
   my symmetry.txt file for part (a) contained the following 2 lines:

   2 3 4
   5 6 7

   The first line contains the IDs of the men (4, 5, and 6) and the second line contains
   the IDs of the women. Your symmetry.txt file may be different, depending on how many 
   semaphores you defined in your solution. To capture the IDS that are being used:
   1. Run reachability testing for a few seconds *without* symmetry reduction; this will 
      create a file named ThreadID.txt, which records the IDs used for the men and women threads.
   2. Use the IDs in ThreadID.txt to create your symmmetry.txt file.

   Note: You may need a different symmetry.txt file for parts (a), (b), and (c).

   Submit your source code and a "statement of correctness" in which you 
   either state that your program is (believed to be) correct or you 
   describe any problems that you are aware of. Also, state the results
   of reachability testing (i.e., the number of sequences that were
   exercised and whether any deadlocks were detected).

   Note: If you downloaded the library files, you can put your UnisexBathroom.java
   file in the same directory as the library files and compile them all using:
    
     javac *.java

   If you are using the jar file, you can put your UnisexBathroom.java
   file in the same directory as the jar file and compile it using:

   Windows: javac -classpath .;ModernMultithreading.jar UnisexBathroom.java
   Unix:    javac -classpath .:ModernMultithreading.jar UnisexBathroom.java

   There are other ways to do it, but this is a simple way that works. If you 
   put your UnisexBathroom.java file and the library/jar files in different 
   directories, you'll need to set your classpath so all the files will be found.

   Note: the Zip file for the library and for the jar file has a UserManual file
   in it. You don't need to read it all now, but take a look when you get a chance.
   There are example program directories in the Zip file also.