Java代写 | CS 5010 Build a Chatroom

本次Java代写是实现一个聊天室

Fall 2019 CS 5010 (PDP): Northeastern University, Seattle Page 1 of 6
A8: Build a Chatroom
CS 5010
Northeastern University—Seattle
Fall 2019
Adrienne Slaughter
[email protected]
This assignment is due 2 December 2019, 6pm. Submissions should be made using your group
repo.
In this assignment, you will build a simple chat room. It will consist of a client and a server. The
server will be responsible for managing the client connections (up to 10 clients can be
connected and in a chat room at one time), accepting messages from one client and sending
the messages to all attached clients. Clients will be able to either send a message that is public
in the chat room, or that goes directly to a single, specified client.
To add some interest to the chatroom, participants can also send a randomly generated insult
to another client in the chatroom. You’ll add this feature by incorporating your random
sentence generator from Assignment 7.
Objectives
• Build competence with socket programming
• Apply your multi-threading skills
• Re-use code you’ve built before as a library
• Programming to an interface (that is, the protocol)
Details
Server
The server is responsible for allowing clients to connect, get a list of all other clients connected,
and disconnect. It also handles sending messages to all clients or just one.
When the server starts up, it should start listening on any available port. Once it is up and
listening, it should print a reasonable message on the console that includes what port it is
listening on (so clients can connect).
The server will need to continually listen for more connections (handling them appropriately),
as well as handle each connected client. The server should handle up to 10 clients connected at
a single time. The server will responsible for listening for commands from the client as well as
sending messages to the client.
Fall 2019 CS 5010 (PDP): Northeastern University, Seattle Page 2 of 6
Client
The client will open a socket to communicate with the server. It will maintain the socket to
listen for incoming messages from the server (public or private messages), as well as listen to
the UI (terminal) for messages from the user to send to the server.
When starting the client, you will need to pass in the IP address (or localhost) and port for
the server. Not providing these details should result in a graceful failure.
Client interface
In addition to your client allowing a user to send messages and all chat room messages to be
displayed, it will require additional commands.
Your client must list all commands when the user types a ? (alone on a line—you can ignore
question marks as part of a message).
Other commands your client must provide for:
• logoff: sends a DISCONNECT_MESSAGE to the server
• who: sends a QUERY_CONNECTED_USERS to the server
• @user: sends a DIRECT_MESSAGE to the specified user to the server
• @all: sends a BROADCAST_MESSAGE to the server, to be sent to all users connected
• !user: sends a SEND_INSULT message to the server, to be sent to the specified user
While the above commands must be implemented, you do not need to call them these words
specifically (you may choose to use different words, and possibly include shortcut commands),
but this functionality needs to exist. You *ARE*, however, required to implement the ‘?’ to print
the command menu. You may have an additional menu command if you would like.
Chatroom Protocol
The application data for the chatroom consists of a sequence of data. The format depends on
what kind of message is being sent. All frames of application data begin with a message
identifier. Strings are sent as a byte array; before a string is sent, an int indicating the length of
the array/string is sent. Each field of a frame will be separated by a single space character.
Example:
The following frame sends a message that a new client is connecting to the server with the
username of “aha”:
19 3 aha
Or as a string: “19 3 aha”.
All of the supported messages/frames are described below.
Fall 2019 CS 5010 (PDP): Northeastern University, Seattle Page 3 of 6
Connect message:
int Message Identifier: CONNECT_MESSAGE
int size of username: integer denoting size of the username being sent
byte[]: username
Connect response:
int Message Identifier: CONNECT_RESPONSE
boolean success: true if connection was successful
int msgSize: size of message sent in response
byte[] message: String in byte[]. If the connect was successful, should respond with a
message such as “There are X other connected clients”. If the connect failed, a message
explaining.
Disconnect message:
int Message Identifier: DISCONNECT_MESSAGE
int size of username: integer denoting size of the username being sent
byte[]: username

Disconnect response:
int Message Identifier: CONNECT_RESPONSE
int msgSize: size of message sent in response
byte[] message: String in byte[]. If the disconnect was successful, the message should
be “You are no longer connected.”. If the disconnect failed, a message explaining.
Query users:
int Message Identifier: QUERY_CONNECTED_USERS
int size of username: integer noting the size of the username
byte[] username: username (who’s requesting)
Query response:
int Message Identifier: QUERY_USER_RESPONSE
int numberOfUsers: if the request fails this will be 0. If there are no other users
connected, this will be 0.
int usernameSize1: length of the first username
byte[] username: username1

int usernameSize2: length of the last username
byte[] username: usernameX
When responding to a query, the server must make sure the request is coming from an
already connected user. A list of all the OTHER connected users will be sent.

Note: The server will need to send a block of data for every connected user.
Broadcast Message:
int Message Identifier: BROADCAST_MESSAGE
int sender username size: length of sender’s username
Fall 2019 CS 5010 (PDP): Northeastern University, Seattle Page 4 of 6
byte[]: sender username
int message size: length of message
byte[]: Message
Server will broadcast this message to all connected users, specifying that it came from
sender. If the sender username is invalid, the server will respond with a
FAILED_MESSAGE.
Direct Message:
int Message Identifier: DIRECT_MESSAGE
int sender username size: length of sender’s username
byte[]: sender username
int recipient username size: length of recipient’s username
byte[]: recipient username
int message size: length of message
byte[]: Message
Sending a direct message will fail if the sender or recipient ID is invalid.
Failed Message:
int Message Identifier: FAILED_MESSAGE
int message size: length of message
byte[]: Message describing the failure.
Send Insult:
int Message Identifier: SEND_INSULT
int sender username size: length of sender’s username
byte[]: sender username
int recipient username size: length of recipient’s username
byte[]: recipient username
The server will randomly generate an insult (from A7’s Random Sentence Generator)
and broadcast it to the chat room. Something like the following should be posted:
aha -> sparky: You mutilated goat.
When the client receives either a BROADCAST_MESSAGE or a DIRECT_MESSAGE, it should print
the message out to the console. When printing out a message, please indicate which username
sent the message in some way.
Message Identifiers
Message Type Value
CONNECT_MESSAGE 19
CONNECT_RESPONSE 20
DISCONNECT_MESSAGE 21
Fall 2019 CS 5010 (PDP): Northeastern University, Seattle Page 5 of 6
QUERY_CONNECTED_USERS 22
QUERY_USER_RESPONSE 23
BROADCAST_MESSAGE 24
DIRECT_MESSAGE 25
FAILED_MESSAGE 26
SEND_INSULT 27
Tips
• Do not simply copy and paste your code from A7 into A8. Package it up into a jar and
include it as a library.
• Be sure to program to the protocol, and ask questions if you have any.
• When you program to the protocol, your server can communicate with someone else’s
client, and vice versa.
• If you would like to enhance the protocol by ADDING message types, you may. If you do
so:
o Be sure to document the new message types and include the documentation (as
an .md or .pdf file) in your project repo
o Ensure that your client and server work with the base protocol, and is NOT
DEPENDENT on the enhanced protocol to work properly
• This is an example of a program that will use multiple threads, but not for the purpose
of attempting to improve throughput.
o It is not possible to implement this project properly without multiple threads.
• It would be lovely to send compliments rather than insults. If you would like to
implement a compliment grammar rather than the insult grammar, you are welcome to
replace the insults with compliments. Feel free to share it with the class if you like.
Logistics
Grading
The correctness grade for this assignment will be based on:
• Following and implementing the protocol correctly
• Properly handling multiple clients on the server side
• Properly handling the UI, sending messages to the server and receiving messages from
the server on the client side.
• Utilizing A7 as a library
Gradle and Github
The Gradle requirements are the same as for the previous assignments.


程序代写代做C/C++/JAVA/安卓/PYTHON/留学生/PHP/APP开发/MATLAB


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