Distributed System Project 2

This project is for COMP90015 Distributed System Project1, 2018 SM1

Team members: Linghan Zhou Xueyang Ding Chenfeng Liao Zhenyuan Ye

Jar file list:

ActivityStreamerClient.jar, ActivityStreamerServer.jar

1. client part Client.java -> the main function entrance of client front-end;

Clientskelecton.java -> the funtion to deal with the messages recieved and sent and response actions to the received messages;

TextFrame.java -> the graphic user interface development part provided to the client users to write activity message, send and disconnecting after connecting to selected server.

2. server part Server.java -> the main function entrance of server-end;

   Connection.java -> a defined data structure that provide the pattern of connections between servers and servers to clients, which contains the operation functions of connecting, disconnecting,writing message and running state screening;

   Listener.java -> the listening function to listen the connection requirement from servers and clients and send the message to the server the listener belongs to;

   Control.java -> this class helps to maintain the runing state of matching servers, which contains the functions of message dealing including the responses to register, authentication, login, activity broadcast, lock request and reply and matching operations for the responses.

   WaitingMessage.java -> a defined data structure that provide the message pattern stored in the waiting queue which used in lock situations while registering to matching the recieved lock messages.

3. other part Settings.java -> a class that defines the initialization settings of clients and servers, also contains the functions including getting information part and setting information.

1. client

demo:

Command (register):
java -jar ActivityStreamerClient.jar -rh 127.0.0.1 -rp 12345 -u username
Command (anonymous login):
java -jar ActivityStreamerClient.jar -rh 127.0.0.1 -rp 12345
Command (login):
java -jar ActivityStreamerClient.jar -rh 127.0.0.1 -rp 12345 -u username
-s secret

Set register and login operations at command line with cli options, -rh value means setting the ip address of remote server that the client is going to connect; -rp value means setting the remote port number on the erver that the client is going to connect; -u means setting the username, -s means setting the secret, a combination of username and secret is used to verify the whether the user is allowed to connect the server.

For example, -rh 178.18.9.16 -rp 2173 -u username1 -s secret1 means the client is going to connect server whose ip adress is 178.18.9.16 at port 2173, with the username of username1 and secret secret1. If the username1 and secret1 combination exist in the server 178.18.9.16, the client will connect to the server and the client-end will provide a GUI to send json-pattern activity message.

After the GUI appearance, users can write activity messages with json pattern in windows, then click send-button, the message will be send to all servers and clients connected in the system and the message recieved by the client will also appear in the window. While click the disconnect button, the connection between the client and the server connected will be closed.

The value of rh and rp must be setted before connection, but the value of username and secret is not necessary, if users wanna login anonymously, users can not set the value of username or set it with "anonymous"; also, if users set username without "anonymous" but do not set the value of secret, the server will register with the username first and then the client will try to login. A client secret will be generated randomly and shown on the command line.

2. server

demo:

Command (launch the first server):
java -jar ActivityStreamerServer.jar -lh 127.0.0.1 -lp 12345
Command (launch other servers):
java -jar ActivityStreamerServer.jar -lh 127.0.0.1 -lp 12345 
-rh 127.0.0.1 -rp 12346 -s secret

In the command line, the input -lh indidates setting the value of localhost, which is the hostname of this server, -lp for localport (port of this server), -rh for remotehost (server hostname it will connect to) and -rp for remoteport (server port it will connect to).

For the first server in the system, only the -lh and -lp should be indicated because there is no server it can connect. Then a random secret will be generated, shown on command window. That secret will be used for all other servers to authenticate.

For all the other servers, not only -lh & -lp but also -rh, -rp and -s should be indicated. Servers will automaticallly connect to another server and authenticate when launching.

1. client

demo;

input: {"hello":"world"}

output: { "command" : "ACTIVITY_BOARDCAST", "activity" : { "authenticated_user" : "anonymous", "hello" : "world" } }

When starting to run, the client will try to connect the a selected server. After successfully connect to the server, a GUI window for the client will automatically appear to provide a entrance to send activity messages. Users can write messages on the GUI window and click the send button, then all the connected clients and servers including the sender will receive a responsing activity_broadcast message. Notice all the message should be written in json pattern, like demo above. So that the system can recognize the information, or the system will refuse to send the wrong-format message.

If users want to end the connections between the client and the server connected, clicking disconnect button will make sense, but the relavent GUI will never be automatically closed.

2. server

Servers online should not be concerned, since we assume they never go down.

*** Warning *** While a client connecting to the servers is redirected to another server, the redirection operation will be done automatically, and the GUI window of the old connection will show the redirect message, but the window will never be closed automatically.

Once a server fails (crash/network problem), the system needs enough time to reform it self.