Project 3: GWack (GW Slack Simulator) | CS 2113 Software Engineering - Spring 2022

Project 3: GWack (GW Slack Simulator) #

Watch the videos for this project on this YouTube Playlist

In this project, you will be write a client and server that implements a chat room, similar to Slack (or GWack!). Your client software should be GUI based, and your server software will be command line based.

Preliminaries #

Github Classroom Link:

Testing/Grading #

There is no test scripts. You will be grading based on functionality and OOP design.

What to submit #

You should submit at least the two files:

Compiling and Running your Code #

While you may submit other code, we should be able to compile and run your programs using the following commands.

For the server:

java GwackChannel port

Where port is replaced by the port for the server to bind to.

And for the client GUI, it is run as such.

java GwackCliengGUI

While there is no starter code, and you may design as you see fit, you MAY NOT USE any packages other than what ships with Java. We will not install any third party packages to compile/run your code.

GWack Slack Protocol #

GWack, the GW Slack simulation, is a chat room where multiple clients can message each other. Any message posted to the chatroom will be sent to the server and then relayed to all connected clients. As part of this project, you will be implement both a client GUI that connect to a server and the server that hosts the chat room, or GWack channel.

Public channels for testing #

To facilitate testing, we are hosting three channels you can connect to and interact with:

host: port: 8886
host: port: 8887
host: port: 8888

IMPORTANT: These channels are shared for the entire class. We will monitor the connections and what is posted to these channels. Any behavior considered hateful (broadly defined) may result in disciplinary and academic actions.

Client/Server Protocol #

So that everyone’s GWack client to can interact with each other and the public channels, we must define a standard protocol.

Initial Handshake #

When a client first connect, it sends the following information to the server.


Note that there are newlines \n here. It is important for parsing you send each as a complete line. So your server can read a line, then expect the next line, and so on.

Note that username should be replace with whatever this client chooses as a username. Like if they were named george it would be george instead of username

If successful, the server responds with the member list (see below), otherwise, the server will simply close the connection.

Member List Updates #

One feature of the GWack chanel is that you can view all the members of the channel. This is done by the server regularly distributing a list of members in the channel. These messages are always of the following form


Note that username1 … will be the names chosen by the users.

... is indicate that all the clients should be listed here, and is not part of the protocol.

Sending/Receiving Messages #

All other communications are considered as channel messages. Client simply sends one line a message at a time to the server. For example, supposer username send the following message to the server

GWack is so much better than slack

When the server receives that message, it then distributes it to all the clients, including the client that just sent the message inset in []

[username] GWack is so much better than slack

When a client receives a message from the server, it will display that it in the display panel.

GWack Client (70 points) #

You will implemented a threaded, GUI GWack client. Here’s a visual of my implementation of the GWack Client. Yours can have different design and features, as long as the major features are there.

Here’s a visual of a connected client mid-message.

GUI Display

Connecting and Disconnecting #

You should have a mechanism for clients to set a name, a host/ip address and a port to connect to. There should also be a button for connecting and disconnecting. There also needs to be visuals for when the user is connected vs. not connected.

For example, here is the menu options for a connected

GUI Display Connected

and disconnected

GUI Display Disconnected

You should also consider making the text-areas non-editable once connected as well.

ERROR reporting #

You should have some mechanism for reporting errors with connections. I choose to use message dialogs, like the following. You can use something else, but you have to have something.

GUI Display Error

Some errors to consider:

Message Sending and Display #

You have should have two text display areas.

The first is to display all the messages that have been received. This text area should not be editable.

GUI Display messages

For second messages, this should be editable. There should be some sort of button to initiate a send.

GUI send messages

Additionally, you should have a key listener so that messages send when the user hits ENTER.

Important: the user can either send a message by hitting “ENTER” or clicking the button.

Members in the channel #

There should be a display for the current members in the channel. This should update as the members come and go, but it should not be editable by the user.

GUI members display

GWack Server (20 points) #

Your GWack server (GWackChannel) should host a single chatroom or channel at a specified port, provided as a command line argument. The remaining requirements of the server are as follows:

Extra Features (up to 30 points) #

Pick any (or all) the following features to add your GWack client and server. The max points you can achieve is 20 points — that is you can earn a grade as high as 120/100 – but you can choose to do any subset of the following additional features to receive credit.

IMPORTANT: be sure to clearly describe which of the features you implemented in your README and how we can test them effectively.

YES – you can do the extra features, if they do not affect the server, and earn points instead of implementing the server. We’ve noted some features that are server dependent with (SERVER) tag

Possible feature upgrades: