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java chat in which server send notification to all clients !!!!

Posted on 2004-05-02
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Last Modified: 2010-03-31
hello to all .,

i am trying to make a console ( gui can be better ) client server chat program ( in java ofcourse !!! ) ...which is multithreaded  ( of course !!! )......
...which goes like this ....

client : LOGIN  shehryar         ( " shehyar" will be extracted using substring )
server : clientname , ip ,  port   ( sends this to all clients connected )
client : LOGOFF
server : clientname LOGOFF   ( sends this to all clients conneted )


i have done a hell lot but cant seem to do it in the order specified.........( i am sure the order is pretty comprehensible ) .......

Explaination : when a client gets connected , it types  LOGIN  clientname ....... "clientname" is extracted using subtring ....then server send    ->    clientname  hisIP  hisPORT    to all clients connected  , and when client A types LOGOFF , the server send notification to all clients that  client A has logged off ...

can plz any1 help in this and send me sum code stuff/part..........thanks !!!
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Question by:DahaR
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Expert Comment

by:objects
ID: 10973926
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Expert Comment

by:Mayank S
ID: 10974657
You should maintain a list of all client-Sockets or their PrintWriters in a static Vector or something like that, at the server-side. When a client connects, then add its PrintWriter to the Vector. When a client disconnects, then remove it. While adding/ removing, iterate through the Vector and send a message to all other clients.
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Author Comment

by:DahaR
ID: 10977552
ok !!! but will        out.println(message);       command     ,  send the message to all clients connected or will i have to use synchronization.... or sumthing  ???
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Expert Comment

by:Mayank S
ID: 10978054
If you use a Vector, it is synchronized itself, so you don't need to worry about that. You can store all the PrintWriters in that Vector, loop through it and send the data using out.println ( message ). Be careful not to send it to the same client himself~!
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Author Comment

by:DahaR
ID: 10981373
ok ......lemme check  !!!!  by the way ...have u done anything similar to this program !!! that i can get help from or see !!! thx!!!
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Expert Comment

by:Webstorm
ID: 10981751
Hi all,

You can create a class for each client:

    public class ChatClient
    {
          Socket soc;
          String name,ip,port;  // information about the client
          PrintStream ps; // = new PrintStream( soc.getOutputStream() );
    }

>> If you use a Vector, it is synchronized itself
only during the Vector method call.

The client list may need some synchronization :


    public synchronized void addClient( ChatClient cc )
    {
         sendToAllClients("server: "+cc.name+", "+cc.ip+", "+cc.port);
         clients.add(cc);
    }

    public synchronized void removeClient( PrintStream ps )
    {
        clients.remove(cc);
        sendToAllClients("server: "+cc.name+" LOGOFF");
    }

    public synchronized void sendToAllClients( String msg )
    {
         int nb=clients.size();
         for (int i=0;i<nb;i++)
             ((ChatClient)clients.elementAt(i)).ps.println(msg);
    }


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Accepted Solution

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Webstorm earned 125 total points
ID: 10981756
   public synchronized void removeClient( PrintStream ps )
Should be:
    public synchronized void removeClient( ChatClient cc )
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Author Comment

by:DahaR
ID: 10981878
ok thanks man !!! i'll check it out and then tell ya !!!!!!!
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Author Comment

by:DahaR
ID: 10982818
thanks a lot  WEBSTORM !!!!   yur idea really helped me !!!  

well i have osting another question regarding sending image from server to client using streams......so do check it out....remember my LOGIN plz !!!!!!! see ya ...........
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Expert Comment

by:Mayank S
ID: 10983527
DahaR. do you know that you can split the points between experts who provide an idea and who provide a working solution?
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Expert Comment

by:Mayank S
ID: 10983528
>> only during the Vector method call.

Ah, right.
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Author Comment

by:DahaR
ID: 10984558
sorry man , didnt know  that  :( .....will try to be careful next time .....n'ways thx for the info !!!
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Expert Comment

by:Webstorm
ID: 10984814
Hi mayankeagle,

>> do you know that you can split the points ...
You can post a question to
http://www.experts-exchange.com/Community_Support/askQuestion.jsp

Or i can post a question to give you points.
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Expert Comment

by:Mayank S
ID: 10984964
No, Webstorm, not needed :-) thanks. I just wanted to let DahaR know that it is possible because I had a feeling he didn't know it. I don't have any issues with the PAQing of the question.
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