代做COMP2221、代写Java程序设计

日期：2025-03-22 03:41

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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