School of Computer Science: assessment brief
Module title Networks
Module code COMP2221
Assignment title Coursework
Assignment type
and description
Programming assignment in Java
Rationale
Design and develop client and multi-threaded server ap plications in Java to solve a specified problem
Guidance Detailed guidance provided later in this document
Weighting 30%
Submission dead line
2pm Monday 24th March
Submission
method Gradescope
Feedback provision
Marks and comments for the submitted code returned
via Gradescope
Learning outcomes
assessed
Design, implement and test network protocols and ap plications.
Module lead David Head
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1. Assignment guidance
For this coursework, you will implement client and multi-threaded server applications
for a simple voting system in which the server is initialised with the options to vote
for, and clients can view the current number of votes for each option. Clients can also
vote for one of the options, which is then updated on the server.
This coursework specification is for school Unix machines only, including the remote
access feng-linux.leeds.ac.uk. We cannot guarantee it will work on any other
environment.
2. Assessment tasks
To get started, unarchive the file cwk.zip (you can do this from the command line
by typing unzip cwk.zip). You should then have a directory cwk with the following
structure:
cwk --- client --- Client.java
|
-- server --- Server.java
Empty .java files for the client and server have been provided. Do not change the
names of these files, as we will assume these file and class names when assessing.
You are free to add additional .java files to the client and server directories.
The requirements for the server application are as follows:
• Accept at least two options that can be voted for, each consisting of a single word,
as command line arguments when launched, e.g.
java Server rabbit squirrel duck
• The server should immediately quit with an error message for less than two options.
• Otherwise, it should run continuously.
• Use an Executor to manage a fixed thread-pool with 30 connections.
• If the client makes a vote for <option>, the vote count for <option> should be
increased by 1 (note all vote counts should initially be zero).
• However, if <option> does not exist, an error message should be returned.
• Following a request by a client, return the current state of the poll with one line
per option, where each line contains at least the option and the current count. See
below for an example of valid output.
• Create the file log.txt on the server directory and log every valid client request,
with one line per request, in the following format:
date|time|client IP address|request
where request is one of list or vote, i.e. you do not need to log the option for
vote operations. Do not add other rows (e.g. headers, blank lines) to the log file.
Note that you must create the log file, not overwrite or append an existing file. Any
log.txt file in your submission will be deleted at the start of the assessment.
The requirements for the client application are as follows:
• Accept one of the following commands as command line arguments, and perform
the stated task:
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• list, which displays the current state of the poll from the server and displays
it to the user. Each option should be output on the same line as their current
vote count, with a different line for each option. See below for an example of
valid output.
• vote <option>, which requests that the server increases the vote count for
<option> by 1, and display the message returned by the server.
• Exits after completing each command.
Your server application should listen to the port number 7777. Both the client and the
server should run on the same host, i.e. with hostname localhost.
All communication between the client and server must use sockets – they cannot access
each other’s disk space directly. Your solution must use TCP, but otherwise you are
free to devise any communication format you wish, provided the requirements above
are met.
Neither the client nor the server should expect interaction from the user once they are
executed. In particular, instructions to the Client application must be via command
line arguments. In the case of an invalid input, your client application should quit with
a meaningful error message.
3. General guidance and study support
If you have any queries about this coursework, visit the Teams page for this module. If
your query is not resolved by previous answers, post a new message. Support will also
be available during the timetabled lab sessions.
You will need the material up to and including Lecture 11 to complete this coursework.
You may like to first develop Client.java and Server.java to provide minimal func tionality, following the examples covered in Lectures 7 and 8. You could then add
another class that handles the communication with a single client. This will make
it easier to implement the multi-threaded server using the Executor. Multi-threaded
servers were covered in Lectures 10 and 11. You will need to use input and output
streams; these were covered in Lecture 6.
Example session
First cd to cwk/server, compile, and launch the server with two options to vote for:
> java Server rabbit squirrel
Now in another tab or shell, cd to cwk/client and compile. If you execute the following
commands, the output should be something like that shown below.
>java Client list
’rabbit’ has 0 vote(s).
’squirrel’ has 0 vote(s).
> java Client vote rabbit
Incremented the number of votes for ’rabbit’.
>java Client list
’rabbit’ has 1 vote(s).
’squirrel’ has 0 vote(s).
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> java Client vote duck
Cannot find option ’duck’.
Note your application does not need to follow exactly the same output as in this exam ple, as long as the requirements above are followed.
4. Assessment criteria and marking process
Your code will be checked using an autograder on Gradescope to test for functionality.
Staff will then inspect your code and allocate the marks as per the provided mark
scheme below. This includes the meaningful nature (or not) of error messages output
by your submission.
5. Submission requirements
Remove all extraneous files (e.g. *.class, any IDE-related files etc.). You should then
archive your submission as follows:
(a) cd to the cwk directory
(b) Type cd ..
(c) Type zip -r cwk.zip cwk
This creates the file cwk.zip with all of your files. Make sure you included the -r
option to zip, which archives all subdirectories recursively.
To check your submission follows the correct format, you should first submit using the
link Coursework: CHECK on Gradescope. Only once it passes all of the tests should
you then submit to the actual submission portal, Coursework: FINAL.
The autograder is set up to use the standard Ubuntu image (base image version 22.04)
with OpenJDK 21 installed as follows,
apt-get -y install openjdk-21-jdk
This version of Java most closely matches the RedHat machines in the Bragg teaching
cluster and on feng-linux.leeds.ac.uk.
The following sequence of steps will be performed when we assess your submission.
(a) Unzip the .zip file.
(b) cd to cwk/client directory and compile all Java files: javac *.java
(c) cd to cwk/server directory and do the same.
(d) If there is a log.txt file on the server directory, it will be deleted.
(e) To launch the server, cd to the cwk/server directory and type e.g. java Server
mouse rabbit
(f) To launch a client, cd to the cwk/client directory and type e.g. java Client
list
If your submission does not work when this sequence is followed, you will lose marks.
6. Academic misconduct and plagiarism
Academic integrity means engaging in good academic practice. This involves essential
academic skills, such as keeping track of where you find ideas and information and
referencing these accurately in your work.
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By submitting this assignment you are confirming that the work is a true expression
of your own work and ideas and that you have given credit to others where their work
has contributed to yours.
There is a three-tier traffic light categorisation for using Gen AI in assessments. This
assessment is amber category: AI tools can be used in an assistive role. Use comments
in your code to declare any use of generative AI, making clear what tool was used and
to what extent.
Code similarity tools will be used to check for collusion, and online source code sites
will be checked.
7. Assessment/marking criteria grid
This coursework will be marked out of 30.
11 marks : Basic operation of the Server application, including use of thread
pool and log file output.
11 marks : Implementation of the list and vote commands.
4 marks : Meaningful error messages.
4 marks : Sensible code structure with good commenting.
Total: 30


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