<!-- page03.html,v 1.10 2000/03/19 20:09:23 jcej Exp --> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <META NAME="GENERATOR" CONTENT="Mozilla/4.04 [en] (X11; I; Linux 2.0.32 i486) [Netscape]"> <META NAME="Author" CONTENT="James CE Johnson"> <META NAME="Description" CONTENT="A first step towards using ACE productively"> <TITLE>ACE Tutorial 006</TITLE> </HEAD> <BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> <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%"> <PRE> <font color=red>// page03.html,v 1.10 2000/03/19 20:09:23 jcej Exp</font> <font color=blue>#ifndef</font> <font color=purple>CLIENT_ACCEPTOR_H</font> <font color=blue>#define</font> <font color=purple>CLIENT_ACCEPTOR_H</font> <font color=red>/* The ACE_Acceptor<> template lives in the ace/Acceptor.h header file. You'll find a very consistent naming convention between the ACE objects and the headers where they can be found. In general, the ACE object ACE_Foobar will be found in ace/Foobar.h. */</font> <font color=blue>#include</font> "<A HREF="../../../ace/Acceptor.h">ace/Acceptor.h</A>" <font color=blue>#if !defined</font> (<font color=purple>ACE_LACKS_PRAGMA_ONCE</font>) <font color=blue># pragma</font> <font color=purple>once</font> <font color=blue>#endif</font> <font color=red>/* ACE_LACKS_PRAGMA_ONCE */</font> <font color=red>/* Since we want to work with sockets, we'll need a SOCK_Acceptor to allow the clients to connect to us. */</font> <font color=blue>#include</font> "<A HREF="../../../ace/SOCK_Acceptor.h">ace/SOCK_Acceptor.h</A>" <font color=red>/* The Client_Handler object we develop will be used to handle clients once they're connected. The ACE_Acceptor<> template's first parameter requires such an object. In some cases, you can get by with just a forward declaration on the class, in others you have to have the whole thing. */</font> <font color=blue>#include</font> "<font color=green>client_handler.h</font>" <font color=red>/* Parameterize the ACE_Acceptor<> such that it will listen for socket connection attempts and create Client_Handler objects when they happen. In Tutorial 001, we wrote the basic acceptor logic on our own before we realized that ACE_Acceptor<> was available. You'll get spoiled using the ACE templates because they take away a lot of the tedious details! */</font> typedef ACE_Acceptor <Client_Handler, ACE_SOCK_ACCEPTOR> Client_Acceptor_Base; <font color=red>/* Here, we use the parameterized ACE_Acceptor<> as a baseclass for our customized Client_Acceptor object. I've done this so that we can provide it with our choice of concurrency strategies when the object is created. Each Client_Handler it creates will use this information to determine how to act. If we were going to create a system that was always thread-per-connection, we would not have bothered to extend Client_Acceptor. */</font> class Client_Acceptor : public Client_Acceptor_Base { public: <font color=red>/* This is always a good idea. If nothing else, it makes your code more orthogonal no matter what baseclasses your objects have. */</font> typedef Client_Acceptor_Base inherited; <font color=red>/* Construct the object with the concurrency strategy. Since this tutorial is focused on thread-per-connection, we make that the default. We could have chosen to omitt the default and populate it in main() instead. */</font> Client_Acceptor (int thread_per_connection = 1) : thread_per_connection_ (thread_per_connection) { } <font color=red>/* Return the value of our strategy flag. This is used by the Client_Handler to decide how to act. If 'true' then the handler will behave in a thread-per-connection manner. */</font> int thread_per_connection (void) { return this->thread_per_connection_; } protected: int thread_per_connection_; }; <font color=blue>#endif</font> <font color=red>/* CLIENT_ACCEPTOR_H */</font> </PRE> <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> <P><HR WIDTH="100%"> <CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] [<A HREF="page04.html">Continue This Tutorial</A>]</CENTER>