Question

Write an algorithm each for TCP client and TCP server based on the following specifications: a. TCP client will send a list of 10 numbers to the TCP server. b. TCP server can handle maximum 4 client at a time. TCP server will find the smallest number from the given list and return to the respective client.

Answer 1

//Client
import java.net.*;
import java.io.*;
import java.util.Scanner;

public class Client {
    private Socket socket = null;
    private ObjectInputStream input = null;
    private ObjectOutputStream out = null;

    public Client(String address, int port) {
        try {
            Data data = new Data();
            data.input = new int[10];
            Scanner scanner = new Scanner(System.in);
            socket = new Socket(address, port);
            System.out.println("Connected to the server, enter 10 numbers:");
            for (int i = 0; i < 10; i++) {
                data.input[i] = scanner.nextInt();
            }
            out = new ObjectOutputStream(socket.getOutputStream());
            input = new ObjectInputStream(socket.getInputStream());
            out.writeObject(data);
            System.out.println("Minimum value received from server: " + (Integer)input.readObject());
            input.close();
            out.close();
            socket.close();
        } catch (UnknownHostException u) {
            System.out.println(u);
        } catch (IOException i) {
            System.out.println(i);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    public static void main(String args[]) {
        Client client = new Client("127.0.0.1", 1234);
    }
}

//Server
import java.net.*;
import java.io.*;

public class Server {
    private Socket socket = null;
    private ServerSocket server = null;
    static int NumberOfClients = 0;
    final static int MaximumClients = 4;
    public Server(int port) {
        try {
            server = new ServerSocket(port);
            System.out.println("Server started");
            System.out.println("Waiting for clients");
            while(true) {
                socket = server.accept();
                if(NumberOfClients < MaximumClients) {
                    new ClientManager(socket).start();
                    System.out.println((NumberOfClients+1) + " Clients connected");
                    NumberOfClients++;
                } else {
                    System.out.println("Maximum clients connected");
                    socket.close();
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String args[]) {
        Server server = new Server(1234);
    }
}

//ClientManager to manage single client
import java.io.*;
import java.net.Socket;

public class ClientManager extends Thread {
    private Socket socket = null;
    private ObjectInputStream in = null;
    private ObjectOutputStream out = null;
    public ClientManager(Socket socket) {
        this.socket = socket;
    }
    public void run() {
        try {
            in = new ObjectInputStream(socket.getInputStream());
            out = new ObjectOutputStream(socket.getOutputStream());
            Data data = (Data)in.readObject();
            int min = Integer.MAX_VALUE;
            for(int i = 0; i < 10; i++) {
                if(min > data.input[i]) {
                    min = data.input[i];
                }
            }
            out.writeObject(min);
            out.close();
            in.close();
            socket.close();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            Server.NumberOfClients--;
            e.printStackTrace();
        }
    }
}

//Data that is sent by the client to server
import java.io.Serializable;

public class Data implements Serializable {
    public int input[];
}