ACE/examples/APG/Threads/Condition_Variables.cpp

   1 #include "ace/config-lite.h"
   2 #if defined (ACE_HAS_THREADS)
   3
   4 #include "ace/Task.h"
   5 #include "ace/Synch.h"
   6 #include "ace/Condition_T.h"
   7
   8 // Listing 1 code/ch12
   9 class HA_Device_Repository
  10 {
  11 public:
  12   HA_Device_Repository() : owner_(0)
  13   { }
  14
  15   int is_free ()
  16     { return (this->owner_ == 0); }
  17
  18   int is_owner (ACE_Task_Base* tb)
  19     { return (this->owner_ == tb); }
  20
  21   ACE_Task_Base *get_owner ()
  22     { return this->owner_; }
  23
  24   void set_owner (ACE_Task_Base *owner)
  25     { this->owner_ = owner; }
  26
  27   int update_device (int device_id);
  28
  29 private:
  30   ACE_Task_Base * owner_;
  31 };
  32 // Listing 1
  33
  34 class HA_CommandHandler : public ACE_Task_Base
  35 {
  36 public:
  37   enum {NUM_USES = 10};
  38
  39   HA_CommandHandler (HA_Device_Repository& rep,
  40                      ACE_Condition<ACE_Thread_Mutex> &wait,
  41                      ACE_Thread_Mutex& mutex)
  42     : rep_(rep), waitCond_(wait), mutex_(mutex)
  43   { }
  44
  45   virtual int svc ();
  46
  47 private:
  48   HA_Device_Repository &rep_;
  49   ACE_Condition<ACE_Thread_Mutex> &waitCond_;
  50   ACE_Thread_Mutex &mutex_;
  51 };
  52 // Listing 2 code/ch12
  53 int
  54 HA_CommandHandler::svc ()
  55 {
  56   ACE_DEBUG ((LM_DEBUG,
  57               ACE_TEXT ("(%t) Handler Thread running\n")));
  58
  59   for (int i = 0; i < NUM_USES; i++)
  60     {
  61       this->mutex_.acquire ();
  62       while (!this->rep_.is_free ())
  63         this->waitCond_.wait ();
  64       this->rep_.set_owner (this);
  65       this->mutex_.release ();
  66
  67       this->rep_.update_device (i);
  68
  69       ACE_ASSERT (this->rep_.is_owner (this));
  70       this->rep_.set_owner (0);
  71
  72       this->waitCond_.signal ();
  73     }
  74
  75   return 0;
  76 }
  77 // Listing 2
  78 int
  79 HA_Device_Repository::update_device (int device_id)
  80 {
  81   ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("(%t) Updating device %d\n"),
  82               device_id));
  83
  84   ACE_OS::sleep (1);
  85   return 0;
  86 }
  87 // Listing 3 code/ch12
  88 int ACE_TMAIN (int, ACE_TCHAR *[])
  89 {
  90   HA_Device_Repository rep;
  91   ACE_Thread_Mutex rep_mutex;
  92
  93   //FUZZ: disable check_for_lack_ACE_OS
  94   ACE_Condition<ACE_Thread_Mutex> wait (rep_mutex);
  95   //FUZZ: enable check_for_lack_ACE_OS
  96
  97   HA_CommandHandler handler1 (rep, wait, rep_mutex);
  98   HA_CommandHandler handler2 (rep, wait, rep_mutex);
  99
 100   handler1.activate ();
 101   handler2.activate ();
 102
 103   handler1.wait ();
 104   handler2.wait ();
 105
 106   return 0;
 107 }
 108 // Listing 3
 109
 110 #else
 111 #include "ace/OS_main.h"
 112 #include "ace/OS_NS_stdio.h"
 113
 114 int ACE_TMAIN (int, ACE_TCHAR *[])
 115 {
 116   ACE_OS::puts (ACE_TEXT ("This example requires threads."));
 117   return 0;
 118 }
 119
 120 #endif /* ACE_HAS_THREADS */