Sending data from client to Server

ok i've been looking at a bit of code.
and I still don't know when or how the server recognizes
what data was sent to it.

does a serversocket have a inputstream and output stream too?

or does it just capture that client, and extract the contents from its
input and output stream?

Thanks,

Justin Fox

The ServerSocket does something semi-magical when it accepts a connection. It creates a new socket and converses with the client over the new one. So the server code looks like:

More realistically, a typical server moves the client conversation onto another thread so it can accept the next client call in good time.

See the Sun Concurrency Tutorial for all the good details.

cool, that makes it a lot more clear now.

now for another question.

is the conversation between a client and server synchronized?
by that i mean, when the client writes to its output stream, will the
server wait until its wrote to, before extracting the data from the client's input stream?

if not, could I get some pseudo code illustrating how this happens?

p.s

i saw something about flush() for the streams... does this play a part?

Thanks for the replies,

Justin Fox

I've always done things synchronously ... the client sends a message and closes the socket, the server reads to end of stream which ends because of the close. Then the server responds and closes its stream, and the client reads to end of stream.

I think there's nothing to prevent both ends from reading and writing at the same time. You could try making a server that echoes one byte a time back to the client. See if there's such a thing in the socket tutorial.

if you close the socket, that closes the connection right?

Justin Fox

I have a new question, i have the client sending a message to the server, and the server gets it and prints to the screen, now, how do i send the same message back to the client that sent the message to the server?

Thanks,

Justin Fox

I have the sending done, but it seems that my chatting has a delay for awhile but then it will start working just fine.

for example:

client1 will say "hey" , but client2 will not recieve it.
then client2 will say "hey2", then client2 recieves client1's msg, and then
client1 recieves client2's message just fine, then the conversation is
carried out normally, ived tried to think of wat could cause that.
but I'm stumped.

Thanks for the help,

Justin Fox

Are client1 & client2 using client sockets? Is there a server somewhere?

I fixed it, what was happening is i have a snippet of code like so:
//(pseudocode)

so it wouldn't start the listen thread until that client actually typed something and/or hit enter.

I've seen threadGroups, is that more efficient to keep track of the clients, or do i need to just use a socket array?

if the threadgroup is better, how do i sift thought the threads and pick one out?

Thanks again,

Justin Fox