ACE Tutorial 022

    /* Now that we know the interface, lets proceed to its
          implementation. We obviosuly want to include the corresponding header
          file. */
    #include "Acceptor_Service.h"

    /* A server has to listen for clients at a known
    	TCP/IP port.  The default ACE port is 10002 (at least on my
    	system) and that's good enough for what we want to do here.
    	Obviously, a more robust application would take a command line
    	parameter or read from a configuration file or do some other
    	clever thing.  Just like the signal handler above, though,
    	that's not what we want to focus on, so we're taking the easy
    	way out.  */

    static const u_short PORT = ACE_DEFAULT_SERVER_PORT;

    /* As in all our simple tutorials, our contructor also does nothing */
    Acceptor_Service::Acceptor_Service (void)
    {
      // Constructor
    }

    /* Same in the destructor case */
    Acceptor_Service::~Acceptor_Service (void)
    {
      // Destructor
    }

    /* This is the virtual method inherited from ACE_Service_Object. This
       method is called to initialize the service. In a generic sense, we
       initialize everything that is needed to initialize our service
       here. Ofcourse we need to do that only if there are not already
       initialized. One important point to note here is that we have to
       make sure that everything that is initialized here is actually
       removed when the service is shutdown */
    int
    Acceptor_Service::init (int argc, char *argv[])
    {
      /* As you will see, we will not be using argc and
    	argv here and hence declare them to be unused variables. This
    	helps us from the complaints from the picky compilers about
    	unused variables. */
      ACE_UNUSED_ARG (argc);
      ACE_UNUSED_ARG (argv);

      /* Lets have a debug statement so that we can know that our
         Acceptor_Service will be initialized soon */
      ACE_DEBUG ((LM_DEBUG,
                  "Starting the Acceptor_Service\n"));

      /* Create an ACE_INET_Addr that represents our endpoint of a
        connection. We then open our acceptor object with that Addr.
        Doing so tells the acceptor where to listen for connections.
        Servers generally listen at "well known" addresses.  If not, there
        must be some mechanism by which the client is informed of the
        server's address. */
      if (this->open (ACE_INET_Addr (PORT),
                      ACE_Reactor::instance ()) == -1)
        ACE_ERROR_RETURN ((LM_ERROR,
                           "%p\n",
                           "open"),
                          -1);
      return 0;
    }

    /* This virtual method will be invoked when we pass
    	a directive to the service configurator framework to remove
    	our service. Remember the threads and anything else that are
    	initialized in the init method and remove each of them. If we
    	leave anything that we initialized still running after this
    	method is invoked ...well .. you know what happens :-) */
    int
    Acceptor_Service::fini (void)
    {
        /* Lets have another debug statement to inform us the state of the
         service. */
       ACE_DEBUG ((LM_DEBUG,
                  "Closing down the Acceptor_Service\n"));

        /* Now, lets see what did we start or initialize during the
         initialization process. The only thing that we did was opening
         our Acceptor to start listening for requests. So, lets close it
         down. */
      this->close ();

      return 0;
    }

      /* Now, lets see how we can suspend the service that we initialized
       and is running. By suspension, we mean that the Reactor still knows
       about the service and receives the requests. But, it just keeps
       quite even if there are any requests. It actually queues the
       requests and sends them to the service once it is resumed.*/
    int
    Acceptor_Service::suspend (void)
    {
      /* You must be wondering, as I did, how we can simply suspend this
       service without any complex method invocations. Thanks to our
       ACE_Reactor class, we can actually suspend the service by just
       invoking the following method and passing a pointer to ourself.
       This method actually takes care of all the particulars for
       suspending the services and keeps us happy. */
      ACE_Reactor::instance ()->suspend_handler (this);
      return 0;
    }

    int
    Acceptor_Service::resume (void)
    {
        /* I had the same question again ... how do I do this ?? As before,
         our ACE_Reactor class came to a help with this method. ACE
         classes do make life simpler .. don't they !! */
      ACE_Reactor::instance ()->resume_handler (this);

      return 0;
    }

    /* The macro to be used to define the factory method
    	and destructor for our dynamically loadable service. */
    ACE_SVC_FACTORY_DEFINE (Acceptor_Service)

    /* This macro helps to register a statically linked
       service into the service configurator. It is defined in ace/OS.h. All
       the parameters needed by the service configurator to build and control the
       statically linked servuce are configured in a single structure. An
       instance of this structure is statically initialized using this
       macro. The First parameter is SERVICE_CLASS i.e. the name of the
       class that implements the service. As we did implicitly, this class
       must derive from ACE_Service_Configurator. The second parameter is
       the NAME of the service. This name is used by the service
       configurator to match the configuration options provided in the
       svc.conf file. The third parameter is the type of the object which
       could be either streams or service objects. The next parameter is
       the name of the factory function which we defined in our header
       file and above using the macros ACE_FACTORY_DECLARE and
       ACE_FACTORY_DEFINE. The fifth parameter are a set of options or
       flags which are used to control the ownership and life cycle of the
       object. The final argument helps us to choose if we want a new
       thread for this service. If the argument is not 0, a thread will be
       dedicated to this service. .. lots of parameters .. Huh !! */
    ACE_STATIC_SVC_DEFINE (Acceptor_Service,
                           ACE_TEXT ("Acceptor_Service"),
                           ACE_SVC_OBJ_T,
                           &ACE_SVC_NAME (Acceptor_Service),
                           ACE_Service_Type::DELETE_THIS | ACE_Service_Type::DELETE_OBJ,
                           0)

    #if defined (ACE_HAS_EXPLICIT_TEMPLATE_INSTANTIATION)
    template class ACE_Acceptor ;
    template class ACE_Svc_Handler;
    #elif defined (ACE_HAS_TEMPLATE_INSTANTIATION_PRAGMA)
    #pragma instantiate ACE_Acceptor
    #pragma instantiate ACE_Svc_Handler
    #endif /* ACE_HAS_EXPLICIT_TEMPLATE_INSTANTIATION */

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Last modified: Fri Jan 19 11:37:49 PST 2001