Little bit of thread and little bit of instant messenger design problem

Question

OK! i have a small problem here, i am planning on making a instant messenger server and client, not compatible with any out there(as of yet) and not using any stansard protocols out there, just something i made on my own. ok now the problem i am trying to figure out is....i have a "Messaging Server" as the name suggests it sends messages from one client to the other, how it is setup is, client connects to this server, the server accepts and creates a new thread for this client and adds a message listener to this client handler thread. as and when the server creates this thread for the client, it puts it in a vector which is keeping track of every client connected to this server. so now when the client sends a message to another client, basically it goes through this server, the thread upon receiving this message, fires a method of the listener. this method takes the message, finds out who it is going to(therefore the userid) and seaches the threads vector to find the appropriate thread and then just creats another striped down message out of the received message and calls a method in that thread to send this newly created message and hence the message should be sent.(i am speculating, i still have not created this)
so the problem ia m logically facing is...at what point of time who is taking the load, what i mean by that is, when the thread receives the message, ofcourse it is this thread which is working is taking the load, but when the listener fucntion is fired which thread is handlign the call is it the client handler thread which fired the method or the messaging server thread which creates these threads?? now once that is solved, who(which thread) is doing the work when i call the fucntion in the other thread which i found aftre searching the vector. i mean i am thinking like this cuz i am not much in sink with the way threads work. i am also trying to figure out this to find out the load the server or the threads will be having.
algo example:
class messageServer
     vector currentWorkingThreads;
     messageListener listener;
     main()
          listener = new messageListener(); //should it be here or the other place i am mentioning below
          while(true)
               clientHandler = socket.accept();
               listener = new messageListener(); //should it be here or the other place i am mentioning above
               //create a thread and add this thread object to the vector
               thread.addLisenter(listener);
class messageServerThread
     string userid;
     messageListener lis;
     run()
          object obj = in.readObject();
          lis.sendMessage(obj);
     sendMessage(obj)
          out.writeObject(obj);
          out.flush;
class messageListener
     sendMessage(msSendMessage msg)
          //find the appropriate user thread
          loop(currentWorkingThread.next())
               messageServerThread msgThread = (messageServerThread)currentWorkingThread.element();
               if(msg.userid == msgThread.userid)
                    msReceiveMessage rcvMsg = msg.strip(); //dosent matter what this does, it just strips the unwanted info and returns the type msReceiveMessage
                    msgThread.sendMessage(rcvMsg);
and if this is something out of the line, or not a good way of doing it, can someone help me with the design it would be gr8.
thanx a lot
-Ankur
help would be greatly appreciated.
[email protected]

Answer 1

other, how it is setup is, client connects to this
server, the server accepts and creates a new thread
for this client and adds a message listener to this
client handler thread. as and when the server creates
this thread for the client, it puts it in a vector
which is keeping track of every client connected to
this server.ok so far.
so now when the client sends a message to
another client, basically it goes through this server,
the thread upon receiving this message, fires a method
of the listener. this method takes the message, finds
out who it is going to(therefore the userid) and
seaches the threads vector to find the appropriate
thread and then just creats another striped down
message out of the received message and calls a method
in that thread to send this newly created message andhere you seem to confuse the thread instance and the thread of execution. the thread invoking this method is still the event handling thread (i.e. the receiver thread of the socket). you do not need threads for delivering - this can be done by the receiving sockets' event handling threads. disadvantage: if processing of the message takes significant time then the socket is blocked and cannot process another message.
solution: put the message in an event queue which is processed by one or more threads. (see my example i e-mailed you)
robert
hence the message should be sent.(i am speculating, i
still have not created this)
so the problem ia m logically facing is...at what
point of time who is taking the load, what i mean by
that is, when the thread receives the message,
ofcourse it is this thread which is working is taking
the load, but when the listener fucntion is fired
which thread is handlign the call is it the client
handler thread which fired the method or the messaging
server thread which creates these threads?? now once
that is solved, who(which thread) is doing the work
when i call the fucntion in the other thread which i
found aftre searching the vector. i mean i am thinking
like this cuz i am not much in sink with the way
threads work. i am also trying to figure out this to
find out the load the server or the threads will be
having.
algo example:
class messageServer
vector currentWorkingThreads;
messageListener listener;
main()
listener = new messageListener(); //should it be
e here or the other place i am mentioning below
while(true)
clientHandler = socket.accept();
listener = new messageListener(); //should it be
be here or the other place i am mentioning above
//create a thread and add this thread object to the
he vector
thread.addLisenter(listener);
class messageServerThread
string userid;
messageListener lis;
run()
object obj = in.readObject();
lis.sendMessage(obj);
sendMessage(obj)
out.writeObject(obj);
out.flush;
class messageListener
sendMessage(msSendMessage msg)
//find the appropriate user thread
loop(currentWorkingThread.next())
messageServerThread msgThread =
=
(messageServerThread)currentWorkingThread.element();
if(msg.userid == msgThread.userid)
msReceiveMessage rcvMsg = msg.strip(); //dosent
ent matter what this does, it just strips the unwanted
info and returns the type msReceiveMessage
msgThread.sendMessage(rcvMsg);
and if this is something out of the line, or not a
good way of doing it, can someone help me with the
design it would be gr8.
thanx a lot
-Ankur
help would be greatly appreciated.
[email protected]