COMP5461- Assignment 3: Dining Philosophers Problem Solved

1 Objective

Implement the dining philosopher’s problem using a monitor for synchronization.

2   Source Code
There are five files that come with the assignment. A soft copy of the code is available to download from the course web site. This time the source code is barely implemented (though compiles and runs). You are to complete its implementation.

2.1  File Checklist
      Files distributed with the assignment requirements:

common/BaseThread.java - unchanged

DiningPhilosophers.java - the main()

Philosopher.java - extends from BaseThread

Monitor.java - the monitor for the system

Makefile - take a look

3   Background
This assignment is a slight extension of the classical problem of synchronization – the Dining Philosophers problem. You are going to solve it using the Monitor synchronization construct built on top of Java’s synchronization primitives. The extension refers to the fact that sometimes philosophers would like to talk, but only one (any) philosopher can be talking at a time while they are not eating. If you need help, consult the references at the bottom.

4   Tasks
Make sure you put comments for every task that involves coding to the changes that you’ve made. This will be considered in the grading process.

Task 1: The Philosopher Class

Complete the implementation of the Philosopher class, that is all its methods according to the comments in the code. Specifically, eat(), think(), talk(), and run() methods have to be implemented entirely.

Non-mandatory hints are provided within the code.

Task 2: The Monitor
Implement the Monitor class for the problem. Make sure it is correct, deadlock- and starvation-free implementation that uses Java’s synchronization primitives, such as wait() and notifyAll(); no use of Semaphore objects is allowed. Implement the four methods of the Monitor class; specifically, pickUp(), putDown(), requestTalk(), and endTalk(). Add as many member variables and methods to monitor the conditions outlined below as needed:

A philosopher is allowed to pickup the chopsticks if they are both available. That implies having states of each philosopher as presented in your book. You might want to consider the order in which to pick the chopsticks up.
If a given philosopher has decided to make a statement, they can only do so if no one else is talking at the moment. The philosopher wishing to make the statement has to wait in that case.
Task 3: Variable Number of Philosophers
Make the application to accept a positive integer number from the command line, and spawn exactly that number of philosophers instead of the default one. If there are no command line arguments, the given default should be used. If the argument is not a positive integer, report this fact to the user, print the usage information as in the example below:

% java DiningPhilosophers -7.a

"-7.a" is not a positive decimal integer

Usage: java DiningPhilosophers [NUMBER_OF_PHILOSOPHERS]

%

Use Integer.parseInt() method to extract an int value from a character string.

Test your implementation with the varied number of philosophers. Submit your output from “make regression”.

IMPORTANT: You are allowed to work on a team of 2 students at most (including yourself!). You and your teammate must be in the same section. Any teams of 3 or more students will result in 0 marks for all team members. If your work on a team, ONLY one copy of the assignment is to be submitted for both members. You must make sure that you upload the assignment to the correct directory of Programming Assignment 3 using Moodle. Your instructor will indicate the exact location. Assignments uploaded to the wrong directory will be discarded and no resubmission will be allowed.

Naming convention for uploaded file: Create one zip file, containing all needed files for your assignment using the following naming convention: 

The zip file should be called pa3_studentID, where pa3 is the number of the assignment and studentID is your student ID number.

2   References
Java API: http://java.sun.com/j2se/1.3/docs/api/
http://java.sun.com/docs/books/tutorial/essential/TOC.html#threads