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<META NAME="Author" CONTENT="James CE Johnson">
<META NAME="Description" CONTENT="A first step towards using ACE productively">
<TITLE>ACE Tutorial 006</TITLE>
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<CENTER><B><FONT SIZE=+2>ACE Tutorial 006</FONT></B></CENTER>
<CENTER><B><FONT SIZE=+2>Creating a thread-per-connection server</FONT></B></CENTER>
<P>
<HR WIDTH="100%">
<P>In <A HREF="client_acceptor.h">client_acceptor.h</A>, we've extended
our object just a bit. The primary reason is to allow us to select
the previous single-threaded implementation or our new thread-per-connection
implementation. Client_Acceptor itself doesn't use this information
but makes it available to the Client_Handler objects it creates.
If we wanted a single-strategy implementation, we would have made no changes
to the Tutorial 5 version of this file.
<P>
<HR WIDTH="100%">
<P><FONT FACE="Arial,Helvetica">// $Id: client_acceptor.h,v 1.1 1998/08/30
13:38:27 jcej Exp $</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">#ifndef CLIENT_ACCEPTOR_H</FONT>
<BR><FONT FACE="Arial,Helvetica">#define CLIENT_ACCEPTOR_H</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">/*</FONT>
<BR><FONT FACE="Arial,Helvetica"> The ACE_Acceptor<> template
lives in the ace/Acceptor.h header file. You'll</FONT>
<BR><FONT FACE="Arial,Helvetica"> find a very consitent naming
convention between the ACE objects and the</FONT>
<BR><FONT FACE="Arial,Helvetica"> headers where they can be
found. In general, the ACE object ACE_Foobar will</FONT>
<BR><FONT FACE="Arial,Helvetica"></FONT> <FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica"> be found in ace/Foobar.h.</FONT>
<BR><FONT FACE="Arial,Helvetica"> */</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">#include "ace/Acceptor.h"</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">/*</FONT>
<BR><FONT FACE="Arial,Helvetica"> Since we want to work with
sockets, we'll need a SOCK_Acceptor to allow the</FONT>
<BR><FONT FACE="Arial,Helvetica"> clients to connect to us.</FONT>
<BR><FONT FACE="Arial,Helvetica"> */</FONT>
<BR><FONT FACE="Arial,Helvetica">#include "ace/SOCK_Acceptor.h"</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">/*</FONT>
<BR><FONT FACE="Arial,Helvetica"> The Client_Handler object
we develop will be used to handle clients once</FONT>
<BR><FONT FACE="Arial,Helvetica"> they're connected.
The ACE_Acceptor<> template's first parameter requires</FONT>
<BR><FONT FACE="Arial,Helvetica"> such an object. In
some cases, you can get by with just a forward</FONT>
<BR><FONT FACE="Arial,Helvetica"> declaration on the class,
in others you have to have the whole thing.</FONT>
<BR><FONT FACE="Arial,Helvetica"> */</FONT>
<BR><FONT FACE="Arial,Helvetica">#include "client_handler.h"</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">/*</FONT>
<BR><FONT FACE="Arial,Helvetica"> Parameterize the ACE_Acceptor<>
such that it will listen for socket</FONT>
<BR><FONT FACE="Arial,Helvetica"> connection attempts and create
Client_Handler objects when they happen. In</FONT>
<BR><FONT FACE="Arial,Helvetica"> Tutorial 001, we wrote the
basic acceptor logic on our own before we</FONT>
<BR><FONT FACE="Arial,Helvetica"> realized that ACE_Acceptor<>
was available. You'll get spoiled using the</FONT>
<BR><FONT FACE="Arial,Helvetica"> ACE templates because they
take away a lot of the tedious details!</FONT>
<BR><FONT FACE="Arial,Helvetica"> */</FONT>
<BR><FONT FACE="Arial,Helvetica">typedef ACE_Acceptor < Client_Handler,
ACE_SOCK_ACCEPTOR > Client_Acceptor_Base;</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">/*</FONT>
<BR><FONT FACE="Arial,Helvetica"> Here, we use the parameterized
ACE_Acceptor<> as a baseclass for our customized</FONT>
<BR><FONT FACE="Arial,Helvetica"> Client_Acceptor object.
I've done this so that we can provide it with our choice</FONT>
<BR><FONT FACE="Arial,Helvetica"> of concurrency strategies
when the object is created. Each Client_Handler it</FONT>
<BR><FONT FACE="Arial,Helvetica"> creates will use this information
to determine how to act. If we were going</FONT>
<BR><FONT FACE="Arial,Helvetica"> to create a system that was
always thread-per-connection, we would not have</FONT>
<BR><FONT FACE="Arial,Helvetica"> bothered to extend
Client_Acceptor.</FONT>
<BR><FONT FACE="Arial,Helvetica"> */</FONT>
<BR><FONT FACE="Arial,Helvetica">class Client_Acceptor : public Client_Acceptor_Base</FONT>
<BR><FONT FACE="Arial,Helvetica">{</FONT>
<BR><FONT FACE="Arial,Helvetica">public:</FONT>
<BR><FONT FACE="Arial,Helvetica">
/*</FONT>
<BR><FONT FACE="Arial,Helvetica">
This is always a good idea. If nothing else, it makes your code more</FONT>
<BR><FONT FACE="Arial,Helvetica">
orthogonal no matter what baseclasses your objects have.</FONT>
<BR><FONT FACE="Arial,Helvetica">
*/</FONT>
<BR><FONT FACE="Arial,Helvetica">
typedef Client_Acceptor_Base inherited;</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">
/*</FONT>
<BR><FONT FACE="Arial,Helvetica">
Construct the object with the concurrency strategy. Since this tutorial</FONT>
<BR><FONT FACE="Arial,Helvetica">
is focused on thread-per-connection, we make that the default. We
could</FONT>
<BR><FONT FACE="Arial,Helvetica">
have chosen to omitt the default and populate it in main() instead.</FONT>
<BR><FONT FACE="Arial,Helvetica">
*/</FONT>
<BR><FONT FACE="Arial,Helvetica">
Client_Acceptor( int _thread_per_connection = 1 )</FONT>
<BR><FONT FACE="Arial,Helvetica">
: thread_per_connection_(_thread_per_connection)</FONT>
<BR><FONT FACE="Arial,Helvetica">
{</FONT>
<BR><FONT FACE="Arial,Helvetica">
}</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">
/*</FONT>
<BR><FONT FACE="Arial,Helvetica">
Return the value of our strategy flag. This is used by the Client_Handler</FONT>
<BR><FONT FACE="Arial,Helvetica">
to decide how to act. If 'true' then the handler will behave in a</FONT>
<BR><FONT FACE="Arial,Helvetica">
thread-per-connection manner.</FONT>
<BR><FONT FACE="Arial,Helvetica">
*/</FONT>
<BR><FONT FACE="Arial,Helvetica">
int thread_per_connection(void)</FONT>
<BR><FONT FACE="Arial,Helvetica">
{ return this->thread_per_connection_; }</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">protected:</FONT>
<BR><FONT FACE="Arial,Helvetica">
int thread_per_connection_;</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">};</FONT><FONT FACE="Arial,Helvetica"></FONT>
<P><FONT FACE="Arial,Helvetica">#endif // CLIENT_ACCEPTOR_H</FONT>
<P>
<HR WIDTH="100%">
<P>Ok, so far we haven't done much to change our concurrency strategy.
Let's move on to the Client_Handler and see if it has changed any.
<P>
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