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// -*- C++ -*-
#include "orbsvcs/LoadBalancing/LB_Random.h"
#include "tao/ORB_Constants.h"
#include "ace/OS_NS_time.h"
#include "ace/os_include/os_netdb.h"
ACE_RCSID (LoadBalancing,
LB_Random,
"$Id$")
#ifdef ACE_HAS_PTHREADS_STD
static pthread_once_t tao_lb_once_control = PTHREAD_ONCE_INIT;
#endif /* ACE_HAS_PTHREADS_STD */
TAO_BEGIN_VERSIONED_NAMESPACE_DECL
extern "C" void tao_lb_random_init_routine (void)
{
ACE_OS::srand (static_cast<unsigned int> (ACE_OS::time ()));
}
TAO_LB_Random::TAO_LB_Random (PortableServer::POA_ptr poa)
: poa_ (PortableServer::POA::_duplicate (poa))
{
TAO_LB_Random::init ();
}
char *
TAO_LB_Random::name (void)
{
return CORBA::string_dup ("Random");
}
CosLoadBalancing::Properties *
TAO_LB_Random::get_properties (void)
{
CosLoadBalancing::Properties * props = 0;
ACE_NEW_THROW_EX (props,
CosLoadBalancing::Properties,
CORBA::NO_MEMORY (
CORBA::SystemException::_tao_minor_code (
TAO::VMCID,
ENOMEM),
CORBA::COMPLETED_NO));
return props;
}
void
TAO_LB_Random::push_loads (
const PortableGroup::Location & /* the_location */,
const CosLoadBalancing::LoadList & /* loads */)
{
throw CosLoadBalancing::StrategyNotAdaptive ();
}
CosLoadBalancing::LoadList *
TAO_LB_Random::get_loads (CosLoadBalancing::LoadManager_ptr load_manager,
const PortableGroup::Location & the_location)
{
if (CORBA::is_nil (load_manager))
throw CORBA::BAD_PARAM ();
return load_manager->get_loads (the_location);
}
CORBA::Object_ptr
TAO_LB_Random::next_member (
PortableGroup::ObjectGroup_ptr object_group,
CosLoadBalancing::LoadManager_ptr load_manager)
{
if (CORBA::is_nil (load_manager))
throw CORBA::BAD_PARAM ();
PortableGroup::Locations_var locations =
load_manager->locations_of_members (object_group);
return TAO_LB_Random::_tao_next_member (object_group,
load_manager,
locations.in ());
}
void
TAO_LB_Random::analyze_loads (
PortableGroup::ObjectGroup_ptr /* object_group */,
CosLoadBalancing::LoadManager_ptr /* load_manager */)
{
}
PortableServer::POA_ptr
TAO_LB_Random::_default_POA (void)
{
return PortableServer::POA::_duplicate (this->poa_.in ());
}
CORBA::Object_ptr
TAO_LB_Random::_tao_next_member (
PortableGroup::ObjectGroup_ptr object_group,
CosLoadBalancing::LoadManager_ptr load_manager,
const PortableGroup::Locations & locations)
{
const CORBA::ULong len = locations.length ();
if (len == 0)
throw CORBA::TRANSIENT ();
// Pick a random location in the sequence using the higher order
// bits (zero based indexing).
//
// See Numerical Recipes in C: The Art of Scientific Computing
// (William H. Press, Brian P. Flannery, Saul A. Teukolsky,
// William T. Vetterling; New York: Cambridge University Press,
// 1992 (2nd ed., p. 277)) for details on why using the lower order
// bits, as in (rand() % 10), is bad. In particular, the lower
// order bits in older rand() implementations may not be as random
// as the higher order bits.
//
// @todo It would be better to use the random() function since it
// is supposed to have a larger period than rand(), in
// addition to the fact that the lower order bits should be as
// random as the higher order bits.
// Prevent integer arithmetic overflow.
const CORBA::Float flen = static_cast<CORBA::Float> (len);
const CORBA::ULong i =
static_cast<CORBA::ULong> (flen * ACE_OS::rand () / (RAND_MAX + 1.0));
ACE_ASSERT (i < len);
// ACE_DEBUG ((LM_DEBUG,
// "** Len = %u\t"
// "Location # %u\t"
// "Loc Name = \"%s\"\n",
// len,
// i,
// locations[i][0].id.in ()));
return load_manager->get_member_ref (object_group,
locations[i]);
}
void
TAO_LB_Random::init (void)
{
#ifdef ACE_HAS_PTHREADS_STD
(void) ::pthread_once (&::tao_lb_once_control,
::tao_lb_random_init_routine);
#else
::tao_lb_random_init_routine ();
#endif /* ACE_HAS_PTHREADS_STD */
}
TAO_END_VERSIONED_NAMESPACE_DECL
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