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diff --git a/docs/tutorials/001/page01.html b/docs/tutorials/001/page01.html deleted file mode 100644 index f79c256bbeb..00000000000 --- a/docs/tutorials/001/page01.html +++ /dev/null @@ -1,104 +0,0 @@ -<!-- $Id$ --> -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> -<HTML> -<HEAD> - <TITLE>ACE Tutorial 001</TITLE> - <META NAME="GENERATOR" CONTENT="Mozilla/3.01Gold (Win95; I) [Netscape]"> - <META NAME="Author" CONTENT="James CE Johnson"> - <META NAME="Description" CONTENT="A first step towards using ACE productively"> -</HEAD> -<BODY text = "#000000" link="#000fff" vlink="#ff0f0f" bgcolor="#ffffff"> - - -<CENTER><P><B><FONT SIZE=+2>ACE Tutorial 001<BR> -A Beginners Guide to Using the ACE Toolkit</FONT></B></P></CENTER> - -<hr> -<P>The purpose of this tutorial is to show you how to create a very simple -server capable of handling multiple client connections. Unlike a "traditional" -server application, this one handles all requests in one process. Issues -of multi-processing and multi-threading will be handled in later tutorials.</P> - -<P> -<HR WIDTH="100%"></P> - -<P>What do you need to create a server?</P> - -<OL> -<LI>Something which accepts connections from clients</LI> - -<LI>Something which handles established connections</LI> - -<LI>A main program loop that handles it all</LI> -</OL> - -<P>The ACE Acceptor provides a solution for our first requirement. -This class is given a TCP/IP port number on which it will listen for -incoming connections. When a connection is attempted, the acceptor will -create a new object (the handler) to deal with the client connection while -the acceptor goes back to listening for other connections.</P> - -<P>The ACE EventHandler solves our second requirement. This doesn't -seem obvious now but as we progress through this tutorial it will become -more clear.</P> - -<P>Finally, a simple <I>main()</I> function will provide our program loop. -After any program initialization, it will enter an infinite loop which -waits for connection attempts to the Acceptor or data "events" -on the EventHandler.</P> - -<P> -<HR WIDTH="100%"></P> - -<P>Before we continue, I need to introduce one more ACE concept: the Reactor. -</P> - -<P>I don't want to go into great detail at this time on what the Reactor -is, what it does and how it does it but it is necessary for you to understand -the basic function of a reactor because it is going to be in the first -piece of code you see. The figure below depicts the interrelationships -between the Reactor, the Acceptor and the application handler.</P> -<P> <center> <img src="simple.gif" align=center> </center> - -<P>Briefly:<BR> -The reactor is an object which reacts when things happen to other objects. -These things are called <I>events</I>. The <I>other objects</I> are communications -objects which you have <I>registered</I> with the reactor. At the time -of registration, you also specify which events you are interested in. The -reactor is notified by the operating system when the events of interest -occur within the registered objects. The reactor then uses member functions -of the registered object to process the event. Notice that the reactor -doesn't care what happens because of the event. It is the object's responsibility -to process the event correctly. The reactor simply notifies the object -of the event.</P> - -<P>Why use the reactor?</P> - -<P>That will become clear as the tutorial progresses. For now, however, -a brief answer would be this: it allows multiple simultaneous client connections -to be processed efficiently by a single-threaded server. </P> - -<P>Servers have traditionally created a separate thread or process for -each client served. For large-volume services (such as telnet and ftp) -this is appropriate. However, for small-volume services the overhead of -process creation far outweighs the actual work being done. So... folks -begin using threads instead of processes to handle the clients. This is -good also but still, in some cases, the overhead is too much to bear. Instead, -why not have a single thread handle several clients and use a more intelligent -load-balancing methodology than one-thread-or-process-per-client? -<i>Caveat: Handling all requests in one thread of one process is really -only good when the requests can be handled almost instantaneously.</i> -</P> - -<P>This is where the reactor's power and flexibility come into play. The -developer can create a simple, single-threaded application that is later -modified to thread-per-client, process-per-client or thread-pool solution. -<P> -If all of this is gibberish and makes you think that ACE is way to hard to -learn, don't worry. We'll go into all the details and explain as we go. -I only went into all of this so that it can kick around in the back of your -mind until you need it later. -<P> -<P><HR WIDTH="100%"> -<CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] [<A HREF="page02.html">Continue This Tutorial</A>]</CENTER> - |