Nrthugu

I need to implement a program to transfer files. I decided to make it using a chat template I've made about 1 month ago so I would have a chat with file transfer option.
The transfer should follow the following points:

1- Server only keeps a list of all files provided by connected clients (No file are actually located in the server, only their names)

2- Client "1" requests file "A" then:

if file "A" is located ONLY in client "2", then client "2" should send 100% of the file to client "1"

if file "A" is located in client "2" and client "3" also has file "A", then client "2" should send 50% of the file to client "1" and client "3" should send the other 50%.

(if the file is located in 4 clients i should be 25% each....and so it goes...)

I've already managed to make the server find out wich client is requesting the file and wich clients have it. But now I'm stuck, I don't know how to make the transfer.

Could someone give me an exemple of how to do it? or point me through the right direction?

[I'm aware my code has some flaws and I will fix it later, right now I need to make the transfer happen before working on fixes, so please, unless it's related, try to focus on that]

Server:

package tor;



import java.util.*;

import java.io.*;

import java.net.*;



public class Server extends Thread {



private String cname;

private Socket client;

public static Vector<PrintStream> clients;

public static Vector<String> clientnames;

public static Vector<String> archives;

public Server(Socket client) {

    this.client = client;



}



public static void main(String args) {

    clients = new Vector<PrintStream>();

    clientnames = new Vector<String>();

    archives = new Vector<String>();



    try {



        ServerSocket server = new ServerSocket(2391);

        System.out.println("Server Started!!n");

        while (true) {

            Socket client = server.accept();

            Server s = new Server(client);

            s.start();

        }



    } catch (IOException e) {

        System.out.println("Server could not start ");



    }



}





@Override

public void run() {



    try {

        BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));

        PrintStream out = new PrintStream(client.getOutputStream());

        cname = in.readLine();

        System.out.println(cname + " Connected --- SERVER!");



        if (cname == null) {

            System.out.println("Unknown Name");

            return;

        }

        clientnames.add(cname);

        clients.add(out);

        connected(" ********** [", cname, "] Connected! **********");



        String arq;

        int size = in.read();

        System.out.println(size);

        for (int i = 0; i < size; i++) {

            arq = in.readLine();

            archives.add(arq);

        }

        String msg = in.readLine();

        String selected;

        while (true) {

            while (!(msg).equals("/exit") && !(msg).equals("/Exit") && !(msg).equals("/EXIT")) {



                if ((msg).equals("/list") || (msg).equals("/List") || (msg).equals("/list")) {

                    out.println("-------- Archives List --------");

                    for (int i = 0; i < archives.size(); i++) {

                        out.println(i+"- "+archives.get(i));

                    }

                    out.println("-------- ******************* --------");

                    msg = in.readLine();

                } else if (msg.equals("/get") || (msg.equals("/GET")) || (msg.equals("/Get"))){

                    msg = in.readLine();

                    int gnum = Integer.parseInt(msg);

                    selected=archives.get(gnum);

                    returnAll("[", out, "]: ", "idreq");

                    out.println("1");

                    reqAll(selected);



                    // I BELIVE HERE IS THE RIGHT PLACE TO MAKE DE TRANSFER CODE





                    msg = in.readLine();

                } else {

                    returnAll("[", out, "]: ", msg);

                    msg = in.readLine();

                }

            }

            msg = in.readLine();

            size = Integer.parseInt(msg);

            for (int i = 0; i <= size; i++) {

                arq = in.readLine();

                for(int j=0;j<archives.size();j++) {

                if (archives.get(j).equals(arq)) {

                    archives.remove(j);

                }

                }

            }

            returnAll(" ********** [", out, "] disconnected ", " ********** ");

            clients.remove(out);

            clientnames.remove(cname);

            client.close();

            break;

        }

    } catch (IOException e) {

        System.out.println("A Client disconnected ");

    }



}



// METHOD TO SEND CONNECTION MESSAGE

public void connected(String msg1, String cname, String msg2) throws IOException {

    Enumeration<PrintStream> e = clients.elements();

    while (e.hasMoreElements()) {

        PrintStream message = (PrintStream) e.nextElement();

        message.println(msg1 + cname + msg2);

    }

}



// METHOD TO RETURN MESSAGE TO ALL CLIENTS

public void returnAll(String msg1, PrintStream saida, String ac, String msg2) throws IOException {

    Enumeration<PrintStream> e = clients.elements();

    while (e.hasMoreElements()) {

        PrintStream message = (PrintStream) e.nextElement();

        message.println(msg1 + cname + ac + msg2);

    }

}



public void reqAll(String req) throws IOException {

    Enumeration<PrintStream> e = clients.elements();

    while (e.hasMoreElements()) {

        PrintStream message = (PrintStream) e.nextElement();

        message.println(req);

    }

}





}

Client:

package tor;



import java.io.*;

import java.net.*;

import java.util.ArrayList;

import java.util.Scanner;





public class Client extends Thread {

    private Socket con;

    private static boolean done = false;

    static ArrayList<String> localArq = new ArrayList<String>();

    static int c=0;



public Client(Socket s) {

    con = s;

}



public static void main(String args) {





    try {

        String ip;

        Scanner s = new Scanner(System.in);

        System.out.print("Enter Server's IP: ");

        ip =s.next();

        Socket con = new Socket(ip, 2391);

        PrintStream out = new PrintStream(con.getOutputStream());

        System.out.println("Connected to Server!");

        System.out.print("Enter your Nickname: ");

        BufferedReader scan = new BufferedReader(new InputStreamReader(System.in));

        String cname = scan.readLine();

        out.println(cname);

        String dir="C:\javator\"+cname;

        Thread t = new Client(con);

        t.start();



        File folder = new File(dir);

        folder.mkdir();

        File listOfFiles = folder.listFiles();

        for (int i = 0; i < listOfFiles.length; i++) {

          if (listOfFiles[i].isFile()) {

            localArq.add(listOfFiles[i].getName());

          }

        }

        int size=localArq.size();

        out.write(size);

        for(int i=0;i<size;i++) {

            out.println(localArq.get(i));

        }





        String msg;

        while (true) {

            System.out.print("");

            msg = scan.readLine();

            if(msg.equals("/ll")) {

            System.out.println("-------- LOCAL LIST --------");

            for (int i = 0; i < localArq.size(); i++) {

                System.out.println(localArq.get(i));

            }

            System.out.println("-------- ******************* --------");

            msg = scan.readLine();

            }else if(msg.equals("/exit") || (msg.equals("/Exit")) || (msg.equals("/EXIT"))) {

                out.println(msg);

                size=localArq.size();

                out.println(size);

                for(int i=0;i<size;i++) {

                    out.println(localArq.get(i));

                }



            }

            else if(msg.equals("/get") || (msg.equals("/GET")) || (msg.equals("/Get"))) {

                System.out.println("Chose file's number to /get: ");

            c++;

            }

            if (done == true) {

                break;

            }

            out.println(msg);

    }

    } catch (UnknownHostException e) {

        System.out.println(e.getMessage());

    } catch (IOException e) {

        System.err.println(e.getMessage());

    }

}



@Override

public void run() {

    try {

        BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));

        String rmsg;

        String req;



        while (true) {

            rmsg = in.readLine();

            if (rmsg == null) {

                System.out.println("Connection Terminated");

                break;

            }else if(rmsg.substring(rmsg.length() - 5).equals("idreq")) {



                req = in.readLine();

                for(int i=0;i<localArq.size();i++) { //IDENTIFIES WHO OWNS THE REQUESTED FILE

                    if(localArq.get(i).equals(req)) {



                        System.out.println("Owns requested file");

                        Socket requester = new Socket("192.168.3.114", 2007);

                        ObjectOutputStream outputr = new ObjectOutputStream(requester.getOutputStream());

                        ObjectInputStream inputr = new ObjectInputStream(requester.getInputStream());

                        Object mens= inputr.readObject();

                        System.out.println(mens);

                        outputr.writeObject("OWNER FOUND");

                    }

                }

                if(c==1) { //IDENTIFIES WHO WANTS THE FILE

                rmsg = in.readLine();

                c= Integer.parseInt(rmsg);

                System.out.println("file: "+req);



                ServerSocket peer = new ServerSocket(2007);

                System.out.println("OPEN FOR CONNECTIONSn");



                    Socket client = peer.accept();

                    System.out.println("Client connected: " + client.getInetAddress().getHostAddress());

                    ObjectOutputStream outputo = new ObjectOutputStream(client.getOutputStream());

                    ObjectInputStream inputo = new ObjectInputStream(client.getInputStream());

                    outputo.flush();

                    outputo.writeObject("Connected to requester");

                    Object mens= inputo.readObject();

                    System.out.println(mens);



                }



            }

             else {

            System.out.println(rmsg);

            }

        }

    } catch (IOException e) {

        e.printStackTrace();

    } catch (ClassNotFoundException e) {

        e.printStackTrace();

    }

    done = true;

}

}

I was able to make a transfer between two clients easily with the information provided and a little research on stackOverflow to understand more about out/inputStreams!
This post also helped me a lot: Sending a file with Java Sockets, losing data
next step is the shared transfer