Java Multi-threaded phone server A Client will: Request a connection with the se

Question

Java Multi-threaded phone server

A Client will:

Request a connection with the server

Send three types of messages through established connection:

STORE messages containing name and phone number

GET messages containing requests for phone number

REMOVE messages containing requests to remove a number from the list

Server will:

Accept requested connections and support multiple connections

Maintain an appropriate data structure (a list) that holds data received from a client. The data stored on server is a list of names and phone numbers which is empty at startup. It is not persistent.

Process messages received from the client:

If message is STORE with a pair of name and number, server will have to update the list of phone numbers.

If message is GET with a request (a name as a content), server has to send to the client the phone number of this name stored in the list

If message is REMOVE with a name, server has to remove this name and number associated with this name from the list.

Client request commands and its format:

STORE Name Phone number

GET Name

REMOVE Name Server response code and meaning:

Data message:

200

Phone number Acknowledgement message:

100 OK

Error message:

300 " Not Found"

Message not understood:

400 "Bad request"

The structure of the Phone server is shown below:

import java.io.*;

import java.util.*;

import java.net.*;

public class PhoneServer {

// The port number on which the server will be listening

private static int port = 2014;

// The server socket.

private static ServerSocket listener = null;

// The client socket.

private static Socket clientSocket = null;

public static void main(String[] args)throws Exception

{

/** Open a server socket on the specified port number(2014)

and monitor the port for connection requests. When a

connection request is received, create a client request

thread, passing to its constructor a reference to the

Socket object that represents the established connection

with the client.

*/

}

}

class ClientThread extends Thread {

Socket socket; //constructor

public ClientThread(Socket socket) { this.socket = socket; }

//implement the run method

public void run() { handleConnection(socket);

} //implement the handleConnection method here.

}

Explanation / Answer

import java.io.*;
import java.util.*;
import java.net.*;

public class PhoneServer { // The port number on which the server will be listening   

private static int port = 2014; // The server socket.

private static ServerSocket listener = null; // The client socket.

private static Socket clientSocket = null;

public static String word = "You bet";

public static void main(String[] args)throws Exception {

boolean listening = true;
try {
listener = new ServerSocket(port);
while (listening) {
new ClientThread(listener.accept()).start();
}
}
catch (Exception e)
{
System.out.println("I/O failure: " + e.getMessage());
}
listener.close();
/** Open a server socket on the specified port number(2014) and monitor the port for connection requests . When a connection request is received, create a client request thread, passing to its constructor a reference to the Socket object that represents the established connection with the client.
*/
}
}

class Contact
{
private String phoneNumber;
private String name;

public Contact(String n, String num) {
this.name = n;
this.phoneNumber = num;
}

public String getName() {
return this.name;
}

public String getNumber() {
return this.phoneNumber;
}
}

class ClientThread extends Thread {
Socket socket; //constructor

public ClientThread(Socket socket) {
this.socket = socket; //Establishes connection
}
// implement the run method
public void run()
{
handleConnection(socket);
}
//implement the handleConnection method here.
public void handleConnection(Socket socket)
{
List<Contact> contacts = new ArrayList<Contact>();

try {
BufferedReader in = new BufferedReader(new
InputStreamReader(socket.getInputStream()));
PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

String fromClient = null;
Boolean quit = false;

out.println("100 OK");

while (!in.ready()) {

}

while ((fromClient = in.readLine()) != null && !quit) {
System.out.println("Received: '" + fromClient + "' "); // Read one line and output it
String[] commands = fromClient.split(" ");
if(commands[0].equals("quit")) {
quit = true;
} else if(commands[0].equals("STORE")) {
contacts.add(new Contact(commands[1], commands[2]));
out.println("100 OK");
} else if(commands[0].equals("GET")) {
for(Contact c : contacts) {
if(c.getName().equals(commands[1])) {
out.println("200 " + c.getNumber());
break;
}
}
} else if(commands[0].equals("REMOVE")) {
for(Contact c : contacts) {
if(c.getName().equals(commands[1])) {
out.println("100 OK");
contacts.remove(c);
break;
}
}
} else {
out.println("400 "Bad request"");
}
}

in.close();
} catch (IOException e) {
//
}

//contact.add(new Contact(32, "OM"));

}
}

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