CST 8221 – JAP - Assignment #2, Part 2

CST 8221 – JAP - Assignment #2, Part 2

Earnings: 7% of your total course mark
Purpose: Writing the Client and Server code
The purpose of Assignment 2 is to build a simple socket based multi-threaded
client/server chat application. In Part 1 of the assignment you have built the GUI
component of the application. In Part 2 of the assignment you are to write the client and
the server code. The application must behave exactly as specified below and shown in
the ClientServerChatScreenCaptures_W20 .pdf.
Requirements Specification:
You have to implement the following classes and interfaces: Accessible,
ChatProtocolConstants, ConnectionWrapper, ChatRunnable, Client, ClientChatUI,
Server, ServerChatUI.
Swing Implementation
Interface Accessible
The interface must contain the following methods:
JTextArea getDisplay()
void closeChat()
Class ChatProtocolConstants
The class must only contain the following static string constants:
CHAT_TERMINATOR="Bye";
DISPLACMENT="\t\t";
LINE_TERMINATOR="\r\n";
HANDSHAKE="hello";
Class ConnectionWrapper
The class must contain the following fields, constructor, and methods:
Fields
ObjectOutputStream outputStream
ObjectInputStream inputStream
Socket socket
Constructor
ConnectionWrapper(Socket socket)
The constructor initializes the socket field only.
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Methods
Socket getSocket()
ObjectOutputStream getOutputStream()
ObjectInputStream getInputStream()
ObjectInputStream createObjectIStreams() throws IOException
The method instantiates an object of ObjectInputStream using the input stream of the
socket, assigns the reference to the inputStream field and returns the inputStream
reference.
ObjectOutputStream createObjectOStreams() throws IOException
The method instantiates an object of ObjectOutputStream using the output stream of
the socket , assigns the reference to the outputStream field and returns the
outputStream reference.
void createStreams() throws IOException
The method instantiates an object of ObjectOutputStream and assigns the reference to
the outputStream field. Then it instantiates an object of ObjectInputStream and assigns
the reference to the inputStream field.
public void closeConnection()throws IOException
The method closes the output stream, the input stream, and the socket. Make sure that
you do not call the close() method on null references. Also make sure that you do not
call close() on a closed socket.
Class ChatRunnable
The class ChatRunnable has the following declaration:
ChatRunnable <T extends JFrame & Accessible> implements Runnable
The class must contain the following fields, constructor, and methods:
Fields
The class must have the following final fields
final T ui
final Socket socket
final ObjectInputStream inputStream
final ObjectOutputStream outputStream
final JTextArea display
Constructor
ChatRunnable (T ui, ConnectionWrapper connection)
The constructor uses the connection parameter and its get methods to initialize the
socket, inputStream, and outputStream fields. It uses the ui parameter to initialize the
display and the ui fields.
Methods
void run()
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The method declares a local variable strin of type String.
Then in an endless loop it performs the following:
1. If the socket is not closed it uses the inputStream to read an object and assign it
to the strin variable. If the socket has been closed it breaks the loop.
2. Trim the strin and compare it to the CHAT_TERMINATOR string. If the trimmed
strin equal to the CHAT_TERMINATOR string, a final string terminate is declared.
Then terminate is assigned a string made of the following substrings:
DISPLACMENT, current date and time, LINE_TERMINATOR, and strin.
For the current date and time you must use the DateTimeFormmater class to
format the date and time returned by the LocalDateTime now() method. The
format must display the name of the month, the day of the month followed by a
comma (,), the time, and the AM or PM. For example: October 31, 13:13 PM
Finally, it uses the display field append() method to append the terminate string
and then it breaks the loop.
3. If during the above operations exceptions are thrown they must be caught and
the loop must be broken.
4. If the strin is not equal to the CHAT_TERMINATOR string, a final string append is
declared. Then append is assigned a string made of the same substrings as
described in item 2 above. Finally, it uses the display field to append the append
string.
If the loop is broken and if the socket is not closed, the outputStream is used to write
the following string:
ChatProtocolConstants.DISPLACMENT+
ChatProtocolConstants.CHAT_TERMINATOR+
ChatProtocolConstants.LINE_TERMINATOR
Finally, before run() method returns it calls the closeChat() method of ui.
Class Server
The Server class is responsible for creating a server socket and starting a server side
chat GUI that will communicate with each individual client.
The main() method should perform the following tasks:
 If command line string is supplied at launch, the method converts the string to an
integer port number. Otherwise, the server must use 65535 as a default port
number and prints on the console that the default port is used.
 The method creates a TCP/IP server socket bound to the specified port.
 The method declares a local variable friend and initializes it to 0.
 In an endless loop the method calls accept() on the server socket instance.
Once a connection with the client is established, the accept() method will return a
Socket instance. Assign that instance to a local Socket variable socket. Use the
following lines statements to set the socket.
 if(socket.getSoLinger()!= -1) socket.setSoLinger(true,5)
 if(!socket.getTcpNoDelay()) socket.setTcpNoDelay(true);
The method prints the socket information on the console screen and increments
the friend variable.
 Next, still in the same loop, a final variable title of type string is declared and
following string is assigned to it: "YourName's Friend "+friend
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 Finally, it call its launchClient() (see Assignment 2 Part 1) with the Socket
instance socket and the title.
The server does not have a GUI. It must started at the command prompt. In order to
stop the server the user must terminate the Java Virtual Machine (JVM) (Ctrl-C).
Class ServerChatUI
The ServerChatUI must inherit from JFrame and Accessible.
Fields
The class must have at least the following fields
JTextField message
JButton sendButton
JTextArea display
ObjectOutputStream outputStream
Socket socket
ConnectionWrapper connection
Constructor
ServerChatUI(Socket socket)
See Assignment 2 Part 1.
Methods
JTextArea getDisplay()
closeChat()
The method tries to close the connection and then disposes the frame.
JPanel createUI()
See Assignment 2 Part 1.
runClient()
The method initializes the connection field with a new ConnectionWrapper. Next, it
uses the connection to create streams and initialize the outputStream field.
Then it creates an object of type Runnable using the ChatRunnable constructor,
creates a thread passing the runnable reference to the Thread constructor and starts
the thread.
Inner Classes
Controller
See Assignment 2 Part 1.
Methods
actionPerformed()
In the actionPerformed() if the Send button is clicked the method call the private send()
method of the Controller.
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send()
The method gets the text from the message text field assigns it to a local variable
sendMessage, appends it to the display adding a line terminator, and then uses the
outputStream to write the following string object:
ChatProtocolConstants.DISPLACMENT
+ sendMessage
+ChatProtocolConstants.LINE_TERMINATOR
If some run-time errors occur during the operation of the method, it must display the
errors on the chat display text area.
WindowController
See Assignment 2 Part 1.
Methods
windowClosing()
First, the method prints on the console the following message:
ServerUI Window closing!
Second, using the outputStream it tries to write the following object:
ChatProtocolConstants.DISPLACMENT
+ChatProtocolConstants.CHAT_TERMINATOR
+ChatProtocolConstants.LINE_TERMINATOR
If an exception occurs during the writing, in the finally clause of the try-catch statement
it disposes the frame.
Third, the method prints on the console the following message:
Closing Chat!
Fourth, using the connection it tries to close the connection. If an exception occurs, in
the finally clause of the try-catch statement it disposes the frame.
Fifth, the method disposes the frame and prints on the console the following message:
Chat closed!
windowClosed()
The method prints on the console the following message:
Server UI Closed!
Class Client
See Assignment 2 Part 1.
Class ClientChatUI
The ClientChatUI must inherit from JFrame and Accessible.
Fields
The class must have at least the following fields
JTextField message
JButton sendButton
JTextArea display
ObjectOutputStream outputStream
Socket socket
ConnectionWrapper connection
Constructor
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ClientChatUI(String title)
See Assignment 2 Part 1.
Methods
JTextArea getDisplay()
closeChat()
If the socket is not closed the method tries to close the connection. Then it calls
enableConnectButton().
JPanel createClientUI()
See Assignment 2 Part 1.
runClient()
See Assignment 2 Part 1.
void enableConnectButton()
The private method enables the Connect button, sets the background of the Connect
button to red, disables the Send button, and request the focus to the host text field.
Inner Classes
Controller
See Assignment 2 Part 1.
Methods
actionPerformed()
First, the method declares a boolean variable connected and initializes it to false.
Second, if the Connect button has been clicked, the method declares a variable host
and assigns to it the string displayed currently in the host text field.
Third, the method declares a variable port of type int. It gets the selected item from the
combo box, converts it to integer and assigns it to the port variable.
Note: If you use only one event handler that implements the ActionListener interface,
you should use getSelectedItem() to get the port number from the combo box.
Fourth, it calls the method connect() and assigns the return value to the connect
variable. If the connect variable is true, the method disables the Connect button, makes
the background color of the Connect blue, enables the Send button, and requests the
focus to the message text field. Then, it creates an object of type Runnable using the
ChatRunnable constructor, creates a thread passing the runnable reference to the
Thread constructor and starts the thread. If the connect variable is false, it method
returns.
Fifth, if the Send button has been clicked, the method calls the private method send().
If some run-time errors occur during the operation of the method, it must display the
errors on the chat display and return.
boolean connect(String host, int port)
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First, the method tries to create a time-out socket. If the socket is successfully created it
assigns the instance to the socket field and then uses the following line to set the
socket:

 if(socket.getSoLinger()!= -1) socket.setSoLinger(true,5)
 if(!socket.getTcpNoDelay()) socket.setTcpNoDelay(true);
Next, it appends the socket information on the chat display text area.
Second, the method creates a new ConnectionWrapper and assigns the returned
reference to the connection field. Then it uses the connection to create streams, and
initializes the outputStream field.
Third, if the operation is successful, it returns true; otherwise it returns false.
If some run-time errors occur during the operation of the method, it must display the
errors on the chat display.
send()
The method gets the text from the message text field assigns it to a local variable
sendMessage, appends it to the display adding a line terminator, and then uses the
outputStream to write the following string object:
ChatProtocolConstants.DISPLACMENT
+ sendMessage
+ChatProtocolConstants.LINE_TERMINATOR
If some run-time errors occur during the operation of the method, it must first call
enableConnectButton() method and then must display the errors on the chat display.
WindowController
See Assignment 2 Part 1.
Methods
windowClosing()
The method using the outputStream tries to write the following object:
ChatProtocolConstants.CHAT_TERMINATOR
If exception occurs it calls System.exit(0); otherwise it calls System.exit(0).
CST8221 – JAP, Assignment 2, Part 2, MMXX Page 8 of 11
JavaFX Implementation
Interface Accessible
See Swing Implementation.
Class ChatProtocolConstants
See Swing Implementation.
Class ConnectionWrapper
See Swing Implementation.
Class ChatRunnable
The class ChatRunnable has the following declaration:
ChatRunnable<T extends Application&Accessable>implements Runnable
For the rest see the Swing Implementation.
Class Server
See Swing Implementation.
The following modification must be made in the Swing implementation:
Before the endless loop the following line must be included:
Platform.setImplicitExit(false);
launchClient(Socket in, String title)
See Assignment 2 Part1.
Class ServerChatUI
The ServerChatUI must inherit from Application and Accessible.
Fields
The class must have at least the following fields
TextField message
Button sendButton
TextArea display
ObjectOutputStream outputStream
Socket socket
ConnectionWrapper connection
Stage primaryStage
String title
Constructor
ServerChatUI(Socket socket, String title)
See Assignment 2 Part 1.
Methods
TextArea getDisplay()
closeChat()
First the method tries close the connection.
Next, the method tries to close the primaryStage.
Note: You must use Platform.runLater() to close the stage.
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Scene createScene()
See Assignment 2 Part 1.
start(Stage primaryStage)
See Assignment 2 Part 1.
Additionally, before showing the stage, the primaryStage must call
setOnCloseRequest(). As a parameter you must provide a lambda expression. In the
body of the lambda expression, you must first print on the console the following
message: Server UI Closed!. Next, you must use the outputStream field to write
the following object:
ChatProtocolConstants.DISPLACMENT,
+ChatProtocolConstants.CHAT_TERMINATOR
+ChatProtocolConstants.LINE_TERMINATOR);
After showing the stage the method call the runClient() method.
runClient()
See Swing implementation.
Inner Classes
BorderedTitledPane
See Assignment 2 Part 1.
Controller
See Assignment 2 Part 1.
Methods
handle()
In the handle() method, if the Send button is clicked the method call the private send()
method.
send()
The method gets the text from the message text field assigns it to a local variable
sendMessage, appends it to the display adding a line terminator, and then uses the
outputStream to write the following string object:
ChatProtocolConstants.DISPLACMENT
+ sendMessage
+ChatProtocolConstants.LINE_TERMINATOR
If some run-time errors occur during the operation of the method, it must display the
errors on the chat display text area.
Class Client
See Assignment 2 Part 1.
Class ClientChatUI
The ClientChatUI must inherit from Application and Accessible.
CST8221 – JAP, Assignment 2, Part 2, MMXX Page 10 of 11
Fields
The class must have at least the following fields
TextField message
Button sendButton
TextArea display
ObjectOutputStream outputStream
Socket socket
ConnectionWrapper connection
Methods
TextArea getDisplay()
closeChat()
See Swing Implementation.
Scene createScene()
See Assignment 2 Part 1.
start()
See Assignment 2 Part 1.
stop()
If the socket is not closed, the method tries to write the following object
ChatProtocolConstants.CHAT_TERMINATOR to the output stream.
void enableConnectButton()
The private method enables the Connect button, sets the background of the Connect
button to red, and disables the Send button.
Inner Classes
Controller
See Assignment 2 Part 1.
Methods
handle()
See Swing Implementation.
send()
See Swing Implementation.
INPORTANT NOTE:
You are allowed (but not required) to work in a team on this part of the assignment
(Assignment 2 Part 2). A team can have two members only. Both members must be
officially registered in the same theory section of the course and must have
demonstrated their Assignment 2 Part 1. If you decide to work in a team, one member
of the team must send me a notification e-mail with the names (first, last) and the
student numbers of the team members. Without a proper and timely (at least two week
before the assignment is due) notification the team work will not be accepted.
CST8221 – JAP, Assignment 2, Part 2, MMXX Page 11 of 11
What to Submit:
Paper submission:
No paper submission is required for this assignment.
Code submission:
Compress in one .zip file all relevant to the assignment .java and .class. Upload the
assignment zip file to Brightspace prior to or on the due date. The name of the zip
file must have the following structure: Student’s family name followed by the last
three digits of the student ID number followed by _JAP_A2P2 , and finally, followed
by your lab section number (for example, s301). Teams must submit one .zip file
only. The name of the file must contain the names of both members e.g.
Name345_Name123_JAP_A2P2_lab section(s).zip.
The submission must follow the course submission standards. The Assignment
Submission Standard and the Assignment Marking Guide are posted on
Brightspace.
Enjoy the assignment. And do not forget that:
“To have a chat you ought to have a friend first.” Society Rule #1
CST8221 – JAP, 27 February 2020, S^R