Re: client server - client problem

From:
Lew <lew@lewscanon.com>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 08 Oct 2007 13:02:46 -0400
Message-ID:
<_Z-dnQHWKNgr_5fanZ2dnUVZ_vWtnZ2d@comcast.com>
solomon13000@gmail.com wrote:

On Oct 8, 11:48 pm, Gordon Beaton <n....@for.email> wrote:

On Mon, 08 Oct 2007 08:24:08 -0700, solomon13...@gmail.com wrote:

Now I open two whiteboards. When I draw one whiteboard-1, the
coordinates are send to the server. Now the server receives the
coordinates and send's the coordinate back to whiteboard-1. The
problem I am facing is it does not return the coordinate to
whiteboard-2 as well. How do I solve the problem?

Your client should be making one connection at initialisation, not one
connection for every mouse event.

Your server needs to maintain more than one connection. Data it
receives on any connection must presumably be sent to all of the
others, but as it's currently written it can still handle only one
client at a time.

Did you read and understand the Java networking tutorial? It shows how
to make a simple server that can handle multiple clients.

The first step to achieving this is to separate the part of the server
that accepts incoming connections from the part that actually handles
the connected clients.

/gordon

--


I implemented threads for my server side.

KKMultiServer.java
------------------

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

public class KKMultiServer
{
    public static void main(String[] args) throws IOException
    {
        ServerSocket serverSocket = null;
        boolean listening = true;

        try
        {
            serverSocket = new ServerSocket(9000);
        }
        catch (IOException e)
        {
            System.err.println("Could not listen on port: 9000.");
            System.exit(-1);
        }

        while (listening)
        new KKMultiServerThread(serverSocket.accept()).start();

        serverSocket.close();
    }
}

KKMultiServerThread.java
------------------------

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

public class KKMultiServerThread extends Thread
{
    private Socket socket = null;
    ObjectOutputStream oos1;
    ObjectInputStream oos2;
    Vector ht1;

    public KKMultiServerThread(Socket socket)
    {
       super("KKMultiServerThread");
       this.socket = socket;
    }

    public void run()
    {
       try
       {
        oos1 = new ObjectOutputStream(socket.getOutputStream());
        oos2 = new ObjectInputStream(socket.getInputStream());

        ht1 = (Vector)oos2.readObject();
        oos1.writeObject(ht1);
       }
       catch(Exception e)
       {
        e.printStackTrace();
       }
    }
}

However it does not send the coordinates to all the clients.


As I pointed out earlier today, and Gordon obliquely mentioned, you are doing
the "writeObject()" call only to the client that sent the object. Where is
the code that would send it to another client? Where is the code that even
recognizes the client?

You still haven't answered why you are using Vector instead of, say,
ArrayList. You can't need the synchronization feature, can you/

Not that it matters, but it piques my curiosity: why did you keep Sun's names
for the server classes?
<http://java.sun.com/docs/books/tutorial/networking/sockets/examples/KKMultiServer.java>

You did put them in named packages, right?

I truly hope you start answering questions.

--
Lew

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