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diff --git a/docs/tutorials/004/page01.html b/docs/tutorials/004/page01.html deleted file mode 100644 index 9eeafe46227..00000000000 --- a/docs/tutorials/004/page01.html +++ /dev/null @@ -1,276 +0,0 @@ -<!-- $Id$ --> -<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 004</TITLE> -</HEAD> -<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> - -<CENTER><B><FONT SIZE=+2>ACE Tutorial 004</FONT></B></CENTER> - -<CENTER><B><FONT SIZE=+2>A much more clever Client</FONT></B></CENTER> - - -<P> -<HR WIDTH="100%"> - -<P>Ok, so the last time around, we learned how to create a simple client -that can send a chunk of data. A cooler thing to do is to overload -the C++ put operator (<<) to put some data for us. That's what -we're going to do this time. (This tutorial is actually where ACE_IOStream -was born.) -<P> -Kirthika says: -<UL> -The cool thing about this "cooler" client is how we use a C++ trick for -streaming incoming data by using the operator<<() method. Also the -Connector portion is wrapped in the open() method which now takes in the -server hostname and port. The result is a cleaner looking client which -successfully interacts with the server when connection is established. -</UL> -<HR WIDTH="100%"> -<PRE> -<font color=red>// $Id$</font> - -<font color=red>/* We need the connector object & we also bring in a simple string - class. */</font> -<font color=blue>#include</font> "<A HREF="../../../ace/SOCK_Connector.h">ace/SOCK_Connector.h</A>" -<font color=blue>#include</font> "<A HREF="../../../ace/SString.h">ace/SString.h</A>" - -<font color=red>/* In this tutorial, we extend SOCK_Stream by adding a few wrappers - around the send_n() method. */</font> -class Client : public ACE_SOCK_Stream -{ -public: - <font color=red>// Basic constructor</font> - Client (void); - - <font color=red>/* Construct and open() in one call. This isn't generally a good - idea because you don't have a clean way to inform the caller when - open() fails. (Unless you use C++ exceptions.) */</font> - Client (const char *server, - u_short port); - - <font color=red>/* Open the connection to the server. Notice that this mirrors the - use of ACE_SOCK_Connector. By providing our own open(), we can - hide the connector from our caller & make it's interaction easier. */</font> - int open (const char *server, - u_short port); - - <font color=red>/* These are necessary if you're going to use the constructor that - invokes open(). */</font> - int initialized (void) { return initialized_; } - int error (void) { return error_; } - - <font color=red>/* This is where the coolness lies. Most C++ folks are familiar - with "<font color=green>cout << some-data.</font>" It's a very handy and easy way to toss - data around. By adding these method calls, we're able to do the - same thing with a socket connection. */</font> - Client &operator<< (ACE_SString &str); - Client &operator<< (char *str); - Client &operator<< (int n); - -protected: - u_char initialized_; - u_char error_; -}; - -<font color=red>/* The basic constructor just sets our flags to reasonable values. */</font> -<font color=#008888>Client::Client</font>(void) -{ - initialized_ = 0; - error_ = 0; -} - -<font color=red>/* This constructor also sets the flags but then calls open(). If the - open() fails, the flags will be set appropriately. Use the two - inline method calls initialized() and error() to check the object - state after using this constructor. */</font> -<font color=#008888>Client::Client</font> (const char *server, - u_short port) -{ - initialized_ = 0; - error_ = 0; - this->open (server, port); -} - -<font color=red>/* Open a connection to the server. This hides the use of - ACE_SOCK_Connector from our caller. Since our caller probably - doesn't care *how* we connect, this is a good thing. */</font> -int -<font color=#008888>Client::open</font> (const char *server, - u_short port) -{ - <font color=red>/* This is right out of Tutorial 3. The only thing we've added is - to set the initialized_ member variable on success. */</font> - - ACE_SOCK_Connector connector; - ACE_INET_Addr addr (port, server); - - if (connector.connect (*this, addr) == -1) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>open</font>"), - -1); - initialized_ = 1; - return 0; -} - -<font color=red>/* The first of our put operators sends a simple string object to the - peer. */</font> -Client & -<font color=#008888>Client::operator</font><< (ACE_SString &str) -{ - <font color=red>/* We have to be able to allow: server << foo << bar << stuff; - - To accomplish that, every << operator must check that the object - is in a valid state before doing work. */</font> - - if (initialized () && !error ()) - { - <font color=red>/* Get the actual data held in the string object */</font> - const char *cp = str.fast_rep (); - - <font color=red>/* Send that data to the peer using send_n() as before. If we - have a problem, we'll set error_ so that subsequent << - operations won't try to use a broken stream. */</font> - if (this->send_n (cp, - <font color=#008888>ACE_OS::strlen</font> (cp)) == -1) - error_ = 1; - } - else - <font color=red>/* Be sure that error_ is set if somebody tries to use us when - we're not initialized. */</font> - error_ = 1; - - <font color=red>/* We have to return a reference to ourselves to allow chaining of - put operations (eg -- "<font color=green>server << foo << bar</font>"). Without the - reference, you would have to do each put operation as a statement. - That's OK but doesn't have the same feel as standard C++ - iostreams. */</font> - return *this ; -} - -<font color=red>/* How do you put a char*? We'll take an easy way out and construct -an ACE_SString from the char* and then put that. It would have been -more efficient to implement this with the body of the -operator<<(ACE_SString&) method and then express that method in terms -of this one. There's always more than one way to do things! */</font> - -Client & -<font color=#008888>Client::operator</font><< (char *str) -{ - ACE_SString newStr (str); - - *this << newStr; - - return *this ; - - <font color=red>/* Notice that we could have been really clever and done: - - return *this << ACE_SString (str); - - That kind of thing just makes debugging a pain though! */</font> -} - -<font color=red>/* ACE_SString and char* are both about the same thing. What do you - do about different datatypes though? - - Do the same thing we did with char* and convert it to ACE_SString - where we already have a << operator defined. */</font> -Client & -<font color=#008888>Client::operator</font><< (int n) -{ - <font color=red>/* Create a character buffer large enough for the largest number. - That's a tough call but BUFSIZ should be quite enough. */</font> - char buf[BUFSIZ]; - - <font color=red>/* Put the number into our buffer... */</font> - <font color=#008888>ACE_OS::sprintf</font> (buf, - "<font color=green>(%d)\n</font>", - n); - - <font color=red>/* And create the ACE_SString that we know how to put. */</font> - ACE_SString newStr (buf); - - <font color=red>/* Send it and... */</font> - *this << newStr; - - <font color=red>/* return ourselves as usual. */</font> - return *this; -} - -<font color=red>/* Now we pull it all together. Like Tutorial 3, we'll allow command - line options. */</font> -int -main (int argc, char *argv[]) -{ - const char *server_host = argc > 1 ? argv[1] : ACE_DEFAULT_SERVER_HOST; - u_short server_port = argc > 2 ? <font color=#008888>ACE_OS::atoi</font> (argv[2]) : ACE_DEFAULT_SERVER_PORT; - int max_iterations = argc > 3 ? <font color=#008888>ACE_OS::atoi</font> (argv[3]) : 4; - - <font color=red>/* Use the basic constructor since the other isn't really very safe. */</font> - Client peer; - - <font color=red>/* Open the server connection. Notice how this is simpler than - Tutorial 3 since we only have to provide a host name and port - value. */</font> - if (peer.open (server_host, - server_port) == -1) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>open</font>"), - -1); - - for (int i = 0; i < max_iterations; i++) - { - <font color=red>/* Tell the server which iteration we're on. No more mucking - aroudn with sprintf at this level! It's all hidden from us. */</font> - peer << "<font color=green>message = </font>" << i+1; - - <font color=red>/* Everything OK? */</font> - if (peer.error ()) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>send</font>"), - -1); - else - <font color=#008888>ACE_OS::sleep</font> (1); - } - - if (peer.close () == -1) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>close</font>"), - -1); - return 0; -} -</PRE> -<HR WIDTH="100%"> - -<P>Ok, now we're done with that. As you can see, it really isn't -so hard to create an object that makes sending data much more "natural" -than the typical send() or send_n() invocation. You can even build -up arbitrary objects and do some neat tricks with C++ templates to stream -their data out as well. (We may go into that a little later.) -Of course, writting the full implementation such that these streams are -interchangable with the standard C++ ostreams is quite a bit more difficult. -In addition, there are a lot of optimizations that this client would benefit -from! - -<P>As an exercise to the reader (don't you hate those!) I challenge you -to write the server side of this. You can take a look at IOStream_Test -in the ACE distribution if you get stuck... - -<P>If you want to compile it yourself, here's the <A HREF="client.cpp">source</A>, -the <A HREF="Makefile">Makefile</A>, -and <A HREF="00SetEnv">Environment -settings</A>. - -<P> -<P><HR WIDTH="100%"> -<CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] </CENTER> - |