diff options
Diffstat (limited to 'docs/tutorials/014/page03.html')
| -rw-r--r-- | docs/tutorials/014/page03.html | 262 |
1 files changed, 0 insertions, 262 deletions
diff --git a/docs/tutorials/014/page03.html b/docs/tutorials/014/page03.html deleted file mode 100644 index 03d5a41fe14..00000000000 --- a/docs/tutorials/014/page03.html +++ /dev/null @@ -1,262 +0,0 @@ -<!-- $Id$ --> -<HTML> -<HEAD> - <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> - <META NAME="Author" CONTENT="Bob McWhirter"> - <TITLE>ACE Tutorial 014</TITLE> -</HEAD> -<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> - -<CENTER><B><FONT SIZE=+2>ACE Tutorial 014</FONT></B></CENTER> - -<CENTER><B><FONT SIZE=+2>ACE_Stream Tutorial, Of Sorts</FONT></B></CENTER> - -<P> -<HR WIDTH="100%"> -<P> -Before we get to main () let's take a look at the Task implementation. - While we've overridden several methods, the real work is done in - the close () and svc () methods. -<P> -Notice how close () figures out if it is being called by the shutdown - of the ACE_Stream or by the exit of svc (). The magic here is - provided by the <i>flags</i> parameter. By handling the stream - shutdown in this way, we don't have to do anything strange in - svc (). We also don't end up with extra hangup messages in the - queue when the dust all settles down. -<P> -Like our other tutorials, svc () looks for a hangup and processes data. -<P> -<HR WIDTH="100%"> -<PRE> - -<font color=red>// $Id$</font> - -<font color=red>// Task.cxx</font> -<font color=red>//</font> -<font color=red>// Tutorial regarding a way to use ACE_Stream.</font> -<font color=red>//</font> -<font color=red>// written by bob mcwhirter (bob@netwrench.com)</font> -<font color=red>//</font> -<font color=red>//</font> - -<font color=blue>#include</font> <ace/Message_Block.h> - -<font color=blue>#include</font> "<font color=green>Task.h</font>" - -<font color=#008888>Task::Task</font> (const char * nameOfTask, - int numberOfThreads) - : d_numberOfThreads (numberOfThreads), - d_barrier (numberOfThreads) -{ - <font color=red>// Just initialize our name, number of threads, and barrier.</font> - - <font color=#008888>ACE_OS::strcpy</font> (d_nameOfTask, nameOfTask); -} - -<font color=#008888>Task::~Task</font> (void) -{ - ACE_DEBUG ((LM_DEBUG, "<font color=green> (%P|%t) %s <font -color=#008888>Task::~Task</font> () -- once per Task\n</font>", d_nameOfTask)); -} - -int <font color=#008888>Task::open</font> (void *arg) -{ - ACE_UNUSED_ARG (arg); - - ACE_DEBUG ((LM_DEBUG, "<font color=green> (%P|%t) %s <font -color=#008888>Task::open</font> () -- once per Task\n</font>", d_nameOfTask)); - - <font color=red>// call <font color=#008888>ACE_Task::activate</font> () to spawn the threads using</font> - <font color=red>// our <font color=#008888>Task::svc</font> () as the function to be run.</font> - - <font color=red>// No need to use THR_DETACHED here, we're going to wait ()</font> - <font color=red>// for the threads to exit later. No leaks.</font> - - return this->activate (THR_NEW_LWP, d_numberOfThreads); -} - -int <font color=#008888>Task::put</font> (ACE_Message_Block *message, - ACE_Time_Value *timeout) -{ - <font color=red>// ACE_Stream uses the put () method of Tasks to send messages.</font> - <font color=red>// This defaultly does nothing. Here we link our put () method</font> - <font color=red>// directly to our putq () method, so that Messages put () to us</font> - <font color=red>// will appear in the Message_Queue that is checked by the</font> - <font color=red>// service threads.</font> - - return this->putq (message, timeout); -} - -int <font color=#008888>Task::close</font> (u_long flags) -{ - - <font color=red>// When the Stream closes the Module, the Module then close ()'s the Task</font> - <font color=red>// and passing a value of (1) as the flag.</font> - - <font color=red>// When a service thread exits, it calls close () with a value that is not</font> - <font color=red>// (1).</font> - - <font color=red>// We use this fact to tell the difference between closing a service thread,</font> - <font color=red>// and closing the main Task itself.</font> - - if (flags == 1) { - - <font color=red>// The Module has asked to close the main Task.</font> - - ACE_DEBUG ((LM_DEBUG, "<font color=green> (%P|%t) %s <font -color=#008888>Task::close</font> () -- flags == 1 -- once per Task\n</font>", d_nameOfTask)); - - <font color=red>// We create a Message_Block of type MB_HANGUP.</font> - - ACE_Message_Block *hangupBlock; - - <font color=red>// Note the use of the lock_adapter () to ensure proper serialization.</font> - ACE_NEW_RETURN (hangupBlock, - ACE_Message_Block (0, - ACE_Message_Block::MB_HANGUP, - 0, - 0, - 0, - Task::lock_adapter ()), - -1); - - <font color=red>// We then send this Block into the Message_Queue to be seen by the</font> - <font color=red>// service threads.</font> - - <font color=red>// Once again we duplicate () the Block as send it off...</font> - - if (this->putq (hangupBlock->duplicate ()) == -1) { - ACE_ERROR_RETURN ((LM_ERROR, "<font color=green>%p\n</font>","<font color=green><font color=#008888>Task::close</font> () putq</font>"), -1); - } - - <font color=red>// ..and we're free to release () our copy of it.</font> - - hangupBlock->release (); - - <font color=red>// Now, all we have to do is wait () for the service threads to all</font> - <font color=red>// exit. This is where using THR_DETACHED in the activate () method</font> - <font color=red>// will come back to haunt you.</font> - - <font color=red>// The Stream waits until this returns before attempting to remove</font> - <font color=red>// the next Module/Task group in the Stream. This allows for an</font> - <font color=red>// orderly shutting down of the Stream.</font> - - return this->wait (); - - - } else { - - ACE_DEBUG ((LM_DEBUG, "<font color=green> (%P|%t) %s <font -color=#008888>Task::close</font> () -- flags != 1 -- once per servicing thread\n</font>", d_nameOfTask)); - - <font color=red>// This is where we can clean up any mess left over by each service thread.</font> - <font color=red>// In this Task, there is nothing to do.</font> - - } - - return 0; - -} - -int <font color=#008888>Task::svc</font> (void) -{ - - <font color=red>// This is the function that our service threads run once they are spawned.</font> - - ACE_DEBUG ((LM_DEBUG, "<font color=green> (%P|%t) %s <font -color=#008888>Task::svc</font> () -- once per servicing thread\n</font>", d_nameOfTask)); - - <font color=red>// First, we wait until all of our peer service threads have arrived</font> - <font color=red>// at this point also.</font> - - d_barrier.wait (); - - ACE_Message_Block *messageBlock; - - while (1) { - - <font color=red>// And now we loop almost infinitely.</font> - - <font color=red>// getq () will block until a Message_Block is available to be read,</font> - <font color=red>// or an error occurs.</font> - - if ( this->getq (messageBlock, 0) == -1) { - ACE_ERROR_RETURN ((LM_ERROR, "<font color=green>%p\n</font>","<font color=green><font color=#008888>Task::svc</font> () getq</font>"), -1); - } - - if (messageBlock->msg_type () == <font color=#008888>ACE_Message_Block::MB_HANGUP</font>) { - - <font color=red>// If the Message_Block is of type MB_HANGUP, then we're being asked</font> - <font color=red>// to shut down nicely.</font> - - ACE_DEBUG ((LM_DEBUG, "<font color=green> (%P|%t) %s <font -color=#008888>Task::svc</font> () -- HANGUP block received\n</font>", d_nameOfTask)); - - <font color=red>// So, we duplicate the Block, and put it back into the Message_Queue,</font> - <font color=red>// in case there are some more peer service threads still running.</font> - - if (this->putq (messageBlock->duplicate ()) == -1) { - ACE_ERROR_RETURN ((LM_ERROR, "<font color=green>%p\n</font>","<font color=green><font color=#008888>Task::svc</font> () putq</font>"), -1); - } - - <font color=red>// We release our copy of the Block.</font> - messageBlock->release (); - - <font color=red>// And we break out of the nearly infinitely loop, and</font> - <font color=red>// head towards close () ourselves.</font> - break; - } - - <font color=red>// If we're here, then we've received a Message_Block that was</font> - <font color=red>// not informing us to quit, so we're assuming it's a valid</font> - <font color=red>// meaningful Block.</font> - - ACE_DEBUG ((LM_DEBUG, "<font color=green> (%P|%t) %s <font color=#008888>Task::svc</font> () -- Normal block received\n</font>", d_nameOfTask)); - - <font color=red>// We grab the read-pointer from the Block, and display it through a DEBUG statement.</font> - - ACE_DEBUG ((LM_DEBUG, "<font color=green> (%P|%t) %s <font color=#008888>Task::svc</font> () -- %s\n</font>", d_nameOfTask, messageBlock->rd_ptr () )); - - <font color=red>// We pretend that this takes to time to process the Block.</font> - <font color=red>// If you're on a fast machine, you might have to raise this</font> - <font color=red>// value to actually witness different threads handling</font> - <font color=red>// blocks for each Task.</font> - - <font color=#008888>ACE_OS::sleep</font> (ACE_Time_Value (0, 250)); - - <font color=red>// Since we're part of a Stream, we duplicate the Block, and</font> - <font color=red>// send it on to the next Task.</font> - - if (put_next (messageBlock->duplicate ()) == -1) { - ACE_ERROR_RETURN ((LM_ERROR, "<font color=green>%p\n</font>","<font color=green><font color=#008888>Task::svc</font> () put_next</font>"), -1); - } - - <font color=red>// And then we release our copy of it.</font> - - messageBlock->release (); - - } - - return 0; - -} - -const char * <font color=#008888>Task::nameOfTask</font> (void) const -{ - return d_nameOfTask; -} - -ACE_Lock_Adapter<ACE_SYNCH_MUTEX> *<font -color=#008888>Task::lock_adapter</font> (void) -{ - return &lock_adapter_; -} - -<font color=red>// Static definition.</font> -ACE_Lock_Adapter<ACE_SYNCH_MUTEX> Task::lock_adapter_; - -</PRE> -<P><HR WIDTH="100%"> -<CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] [<A HREF="page04.html">Continue This Tutorial</A>]</CENTER> - |