Server Socket for chat

[Raghav Mathur]

Hi
I,am using server sockets for making a chat server. i have an applet which lists the clients connected to the chat server. Whenever a client connects to the chat server a window on the server's end is popped up for one to one communication with the connected client . E.g if there are 5 client , there would be 5 windows on the servers's end which would talk to 5 diff clients . What is presently happeneing in my code is whenever a client is coonected a window for chat is popped up at the servers end and one to one communication begins . As soon any other get's connected another window is opened and all the messages are displayed in the latest window(which has recently been popped up).
How can i load diff instances of the frame class to talk to diff connected clients(one to one communication).
Please guide me a bit .
Thanks in adavance

[Peter den Haan]

It is very hard to be specific about what you're doing wrong -- but basically you are having some shared state (a field) somewhere which should not be shared.
This could be a servlet or JSP instance field (always suspect, that), or an application-scoped variable, a static variable, or something else.
- Peter

[Raghav Mathur]

This is the code for server and the client .

  
import java.io.*;
import java.net.*;
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
public class servunis extends Frame implements Runnable,ActionListener
{//1
//static Thread t;
//static Thread t1;
String msg;
Button b ;
static Frame f;
static TextArea ta;
TextArea tf;
Color c;
Socket connection;
InputStream in;
Socket xx;
int x;

//static int acct;
servunis(String title)
 {
 super(title);
 //subthread1 sb = new subthread1(in,xx);
 Panel p1 = new Panel();
 c = new Color(0,102,204);
 setBackground(c);
//setForeground(Color.green);

msg = "indside init()--";
//ta = new TextArea(".",10,55,SCROLLBARS_NONE);
ta = new TextArea(10,55);
ta.setBackground(new Color(16744448));
tf = new TextArea(2,55);

b = new Button("SEND MESSAGE");
p1.add(ta);
p1.add(tf);
p1.add(b);
add(p1);
//f.setSize();
//ta.setText("recieve here ")
ta.setEditable(false);
//b.addActionListener(this);
  } // end of the constructor
public void actionPerformed(ActionEvent ae)
  {
if(ae.getActionCommand().equals("SEND MESSAGE"))
{
//showStatus("clicked");
String strm = tf.getText() + "\n";
ta.append(strm);
tf.setText("");
//tf.gotFocus();
}

  } // end of method actionPerformed
public static void main(String[]arg)
{
servunis su = new servunis("ucs");
Thread t3 = new Thread(su);
t3.start();
 }//e2 end of static void main

public void run()
{

try{//3

ServerSocket server = new ServerSocket(5000);
while(true)
{//4

// the socket object(connection in this case) stores the inetadresses of th clients which get connected to it
connection = server.accept();
System.out.println("the connection has been started from"+ connection.getInetAddress());

f = new servunis("uns");
f.setSize(500,300);
f.setVisible(true);
Thread t = new subthread(connection.getInputStream(),connection);
Thread t1 = new subthread1(connection.getOutputStream());

t.start();
t1.start();
 }// e4
}catch(Exception ee){}

} // end of Run method

//}
//*******************************************************************************
//* The following class creats a separate thread for reading the input from the *
//* client *
//*******************************************************************************
 class subthread extends Thread
{//1
Socket x=null;
InputStream dt=null;
DataInputStream dts=null;
String readitforsubthread;

public subthread(InputStream in , Socket x)
{
this.x=x;
this.dts= new DataInputStream(in);
}
public void run()
{//2
 try{//3
while((readitforsubthread=dts.readLine())!=null)
{
System.out.println(x.getInetAddress()+ "  "+ "says:---"+"  "+readitforsubthread);
//f = new subthread(dt,x);
ta.append(x.getInetAddress()+ "  "+ "says:---"+"  "+ readitforsubthread + "\n");
}
}catch(Exception f2)
{
System.out.println("The client"+x.getInetAddress()+" has disconnected");
System.out.println("**************************************");
}//e3

}//e2  end of run method
}

//**************************************************************************
//*subthread1 starts to write the output          *
//*   *
//**************************************************************************
 class subthread1 extends Thread
{//1
Writer out=null;
int cc;
InputStreamReader ints = new InputStreamReader(System.in);
public subthread1(OutputStream out1)
{
this.out = new OutputStreamWriter(out1);

}

public void run()
{//2
try{//3
while(true)
{//4

cc = ints.read();
out.write(cc);
//out.write(tf.getText());
//System.out.println(tf.getText());
out.flush();
}//e4
}catch(Exception e1){//System.out.println();
}//e3
}//e2 end of run method
}//e1
}// end of the main class
//********************    END OF THE PROGRAMME ********************

_______________code for client____________________

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

public class clientforagni
{
static int i;
public static void main(String[]arg)
{
int send;
try // try1 start
{
System.out.println("The client is ready to send requests to the server");
Socket con = new Socket("give IP here",5000);
System.out.println("connected to "+ con.getInetAddress());

Thread t1 = new write2itagni(con.getOutputStream());
Thread t= new readfromitagni(con.getInputStream());

t1.start();
t.start();
}catch(Exception e2){System.out.println("Server not found");}// catch1 ends

}
}// end of the main method
//********************************************************************

//**************************** subthread starts ************************
class readfromitagni extends Thread
{
String xx;
InputStream in;
DataInputStream dt=null;
public readfromitagni(InputStream in)
{
this.dt=new DataInputStream(in);
}
public void run()
{
try{
while((xx=dt.readLine())!=null)
{
System.out.println(xx);
}
}catch(Exception show){}
}
}
//*********************************Subthread1 class***********************

class write2itagni extends Thread
{
OutputStream out1;
InputStreamReader readfromconsole = new InputStreamReader(System.in);
public write2itagni(OutputStream out)
{
this.out1= out;
}
public void run()
{
try{
while(true)
{
int ll=readfromconsole.read();
if(ll =='@'){System.exit(0);}

out1.write(ll);
out1.flush();
}

}catch(Exception show1){System.out.println("server has been shutdown");}

}
}

Please if you could tell me a bit more where i could be wrong.
Thanks in advance
[ April 12, 2003: Message edited by: raghav mathur ]

[Raghav Mathur]

I've really got stuck ... please if you could help me a bit.
Thanks in advance

[Peter den Haan]

In this case, the shared state I was talking about is the TextArea tf variable in the servunis class. All instances of the subthread1 inner class (and hence all clients) share one copy.
But your real problem goes a bit deeper than that: you are way too fond of instance variables. Virtually all of them should be replaced by method-local variables, and remember always to choose the smallest scope possible, i.e. do not declare all your variables at the start of a method!
And while we're at it, please use the Sun Java coding conventions; your code is almost unreadable. That means SubThread1 instead of subthread1 (although ClientHandlerThread would be a much better name).
- Peter

[Raghav Mathur]

ok . I'll try to explain what the code actually does ( I agree ,it is almost ureadable )
I've made some changes to the initial code.
1) I have a class servunis from where i begin this aplication.In the static void main method i run an infinite loop to accept connections from other clients.
2) Whenever a client gets connected ,I spawn a new Thread(the class is chatterbox) Which pops up a chatting interface and also spawn 2 new threads for accepting input and writing output.
3) There are 2 inner classes inside the chatterbox class named as readingclient and writingclient which are used for taking input from the client and writing output to the client .
4) Now in the class readingclient i,am accepting input from the client and displaying it in a list (the messages).
5) In the writeclient i,am writing text from another interface(frame)to the client.
Its working fine ( one to one )
I guess the only thing i have to do is to merge the the 2 frames(writing and reading)in one single frame.
First of all ... is my design for a one to one chat application correct ?
Second of all .... please also have a look at the code.

  
import java.io.*;
import java.net.*;
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
public class servunis  extends Thread//implements Runnable //,ActionListener
{//1

int x;
int xcnt;
String strm;
String getconn;
Socket xx;
List l;
InputStream in;
public static void main(String[]arg)
{

try{
ServerSocket server = new ServerSocket(5000);
while(true)

{
System.out.println("Start acceptin connections from other users......");
Socket connection = server.accept();
System.out.println(connection.getInetAddress() + "Has just logged in");
Thread t4 = new Thread(new chatterbox("ll",connection));
//pops up a frame for chatting.......................
System.out.println("The Thread for running popping up the frame and start communication....");
t4.start();
}

}catch(Exception ee){}

}
}// end of the main class

//_______________________________________________________________________________________________________

class chatterbox extends Frame implements Runnable//, ActionListener
{
Socket conn;
String tt;
String writetoclient;
String msg;
TextArea ta;
String recvmess;

chatterbox(String tt,Socket conn)
{
super("unistal Customer care");
this.conn = conn;
Panel p1 = new Panel();
setBackground(Color.white);
ta = new TextArea(10,55);
TextArea tf = new TextArea(2,55);
Button b = new Button("SEND MESSAGE");
p1.add(ta);
p1.add(tf);
p1.add(b);
add(p1);
//b.addActionListener(this);
}

public void run()
{
//System.out.println("The main Thread has started");

try{
System.out.println("Reading and Writing operations will now start....");

Thread t = new Thread(new readingclient(conn.getInputStream(),conn));
Thread t1 = new Thread(new writingclient(conn.getOutputStream()));

t.start();
System.out.println("Thread for reading the input has just started....");
t1.start();
System.out.println("Thread for reading the output has just started....");

//ta.appendText("jksskjskj");
//Frame f = new chatterbox("unistal", conn);

//f.setSize(500,300);

//f.setVisible(true);

}catch(Exception ee){}
} // end of Run method
/*
public void actionPerformed(ActionEvent ae)
{
//appentext(
System.out.println("rax");
//ta.appendText("hh");
}
*/
//_______________________________________________________________________________________________________

 class readingclient implements Runnable
 //extends Frame

{
Socket x=null;
DataInputStream dts=null;
String readitforclient;
TextField text;
TextField name;
Button exit,clear;
Label label;
List list;
Panel p1=null;
Panel p2=null;
Panel sp21=null;
Panel sp22=null;
Panel jp=null;

public readingclient(InputStream in , Socket x)
{

this.x=x;
this.dts= new DataInputStream(in);
jp=new Panel();
p1=new Panel();
p2=new Panel();
sp21=new Panel();
sp22=new Panel();
jp.setLayout(new GridLayout(2,1));
p1.setLayout(new GridLayout(1,1));
p2.setLayout(new GridLayout(2,1));
sp21.setLayout(new FlowLayout());
sp22.setLayout(new FlowLayout());

exit = new Button("Exit");
clear = new Button("Clear");
//exit.addActionListener(this);
//clear.addActionListener(this);
list = new List(50);
text = new TextField(43);
name = new TextField(10);
label = new Label("Enter your name");
//name.addKeyListener(this);
p1.add(list);
sp21.add(text);
sp21.add(exit);
sp22.add(label);
sp22.add(name);
sp22.add(clear);
p2.add(sp21);
p2.add(sp22);
jp.add(p1);
jp.add(p2);
add(jp);
setBackground(Color.orange);
setSize(380,300);
setLocation(0,0);
setVisible(true);

}

public void run()
{

 try{
System.out.println("Reading started....");

while((readitforclient=dts.readLine())!=null)
{
System.out.println(x.getInetAddress()+ "  "+ "says:---"+"  "+readitforclient);
recvmess = readitforclient;

//System.out.println("The value of recvmess is" + "" + recvmess);
list.add(readitforclient);
}
//System.out.println(readitforclient);
}catch(Exception f2){System.out.println("The client"+x.getInetAddress()+" has disconnected");
System.out.println("**************************************");
}//e3

}

}// end of class readclient

//____________________________________________________________________________________________________________

//class writingclient extends //Frame implements Runnable,KyListener
class writingclient extends Frame implements Runnable
{

StringBuffer sendmessage;
Writer out=null;
OutputStream out1;
int cc;
TextArea tf ;
BufferedReader br;
//BufferedWriter bw;
TextField text;
TextField name;
Button exit,clear;
Label label;
List list;
Panel p1=null;
Panel p2=null;
Panel sp21=null;
Panel sp22=null;
       Panel jp=null;
public writingclient(OutputStream out1)
{

this.out = new OutputStreamWriter(out1);
jp=new Panel();
p1=new Panel();
p2=new Panel();
sp21=new Panel();
sp22=new Panel();
jp.setLayout(new GridLayout(2,1));
p1.setLayout(new GridLayout(1,1));
p2.setLayout(new GridLayout(2,1));
sp21.setLayout(new FlowLayout());
sp22.setLayout(new FlowLayout());

exit = new Button("Exit");
clear = new Button("Clear");
//exit.addActionListener(this);
//clear.addActionListener(this);
list = new List(50);
text = new TextField(43);
name = new TextField(10);
label = new Label("Enter your name");
//name.addKeyListener(this);
p1.add(list);
sp21.add(text);
sp21.add(exit);
sp22.add(label);
sp22.add(name);
sp22.add(clear);
p2.add(sp21);
p2.add(sp22);
jp.add(p1);
jp.add(p2);
this.add(jp);
setBackground(Color.orange);
setSize(380,300);
setLocation(0,0);
setVisible(true);

}

public void senddata(final Writer outstream1)
{
//this.outstream1 = outstream1;
//outstream1 = outstream;
text.addKeyListener( new KeyListener()
{

public void keyPressed(KeyEvent ke)
{
if(text.equals(ke.getSource()))
{
if(ke.getKeyCode()==KeyEvent.VK_ENTER)
{
//System.out.println("key was hit");
//System.out.println("The value for recvmess is " + "  " + recvmess);

 try{
 outstream1.write(text.getText() + "\n");
 System.out.println(text.getText());
 outstream1.flush();
}catch(Exception erd){}

 list.add(text.getText());
 //readdata();
//System.out.println("The value recv is "+ readitforclient);
 text.setText("");
}
}

 else if(name.equals(ke.getSource()))
   {
   if(ke.getKeyCode()==KeyEvent.VK_ENTER)
   {
   name.setEditable(false);
   text.requestFocus();
   }
     }
}
public void keyReleased(KeyEvent ke)
        {
        //something
        }
        public void keyTyped(KeyEvent ke)
        {
        //something
        }

}
);
} // end of function senddata

public void run()
{
senddata(out);

}

}
}
//********************    END OF THE PROGRAMME ********************

[ April 16, 2003: Message edited by: raghav mathur ]

[Raghav Mathur]

Hi
I,am facing one more problem . As i said earlier I've created 2 class ( 2 frames) . One for reading and onw for writing. Similar code has ben writin on the client .
Now when the server writes a message to the client , it should be displayed to the client and also to the server and similarly for the client.
Now i have one infinite loop at the server's end and one at the client's end which reads the incomming messages and writes back so that it gets displayed on both the chat windows.
As soon as any of the two start sending messages , it obviously gets into an infinite loop .
PS : The code for this is the same as given above . i've not given the client code as it is almost the same .
Thanks in advance

[Raghav Mathur]

HI
The prob i was mentioning has been rectified . The application works fine.
But ..... if i run my main thread from an applet then only the client on the same machine ( where the server resides)are able to to connect . Clients from other machines cannot and i don't even any sort of exceptions.
Any suggestions
Thanks in advance

[Raghav Mathur]

HI Peter
I,am stuck on the last stage of this application that is invoking the server from an applet . But when clients from different machines try to get connected , they fail in doing so . The Code does not give any exceptions ... thiough a client residing on the same machine is able to connect to the server . Is it due the fact that the applet is not letting itself to be shared among the clients cos it doesn't have a static void main method ? .
In that case how am i suppose to display the clients who are conected to the chat server?
If i exclude the Applet model from my application and display the list of clients in a frame which will not be embedded insode a browser)then how will i run my server at www.xyz.com . I,am a bit confused . Kindly help me please . My deadline is near!!
Thanks in advance