lb_loadmanager.h

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      PortableGroup::ObjectGroup_ptr object_group,
      const PortableGroup::Location & the_location
      ACE_ENV_ARG_DECL_WITH_DEFAULTS)
    ACE_THROW_SPEC ((CORBA::SystemException,
                     PortableGroup::ObjectGroupNotFound,
                     PortableGroup::MemberNotFound));

  /// Return the locations of the members in the given ObjectGroup.
  virtual PortableGroup::Locations * locations_of_members (
      PortableGroup::ObjectGroup_ptr object_group
      ACE_ENV_ARG_DECL_WITH_DEFAULTS)
    ACE_THROW_SPEC ((CORBA::SystemException,
                     PortableGroup::ObjectGroupNotFound));

  /// Return the locations of the members in the given ObjectGroup.
  virtual PortableGroup::ObjectGroups * groups_at_location (
      const PortableGroup::Location & the_location
      ACE_ENV_ARG_DECL_WITH_DEFAULTS)
    ACE_THROW_SPEC ((CORBA::SystemException));

  /// Return the ObjectGroupId for the given ObjectGroup.
  virtual PortableGroup::ObjectGroupId get_object_group_id (
      PortableGroup::ObjectGroup_ptr object_group
      ACE_ENV_ARG_DECL_WITH_DEFAULTS)
    ACE_THROW_SPEC ((CORBA::SystemException,
                     PortableGroup::ObjectGroupNotFound));

  /// @note Does this method make sense for load balanced objects?
  virtual PortableGroup::ObjectGroup_ptr get_object_group_ref (
      PortableGroup::ObjectGroup_ptr object_group
      ACE_ENV_ARG_DECL_WITH_DEFAULTS)
    ACE_THROW_SPEC ((CORBA::SystemException,
                     PortableGroup::ObjectGroupNotFound));

  /// TAO specific method
  virtual PortableGroup::ObjectGroup_ptr get_object_group_ref_from_id (
      PortableGroup::ObjectGroupId group_id
      ACE_ENV_ARG_DECL)
    ACE_THROW_SPEC((
       CORBA::SystemException,
       PortableGroup::ObjectGroupNotFound));

  /// Return the reference corresponding to the Replica of a given
  /// ObjectGroup at the given location.
  virtual CORBA::Object_ptr get_member_ref (
      PortableGroup::ObjectGroup_ptr object_group,
      const PortableGroup::Location & loc
      ACE_ENV_ARG_DECL_WITH_DEFAULTS)
    ACE_THROW_SPEC ((CORBA::SystemException,
                     PortableGroup::ObjectGroupNotFound,
                     PortableGroup::MemberNotFound));

  //@}

  /**
   * @name PortableGroup::GenericFactory methods
   *
   * Methods required by the PortableGroup::GenericFactory interface.
   */
  //@{

  /**
   * Create an object of the specified type that adheres to the
   * restrictions defined by the provided Criteria.  The out
   * FactoryCreationId parameter may be passed to the delete_object()
   * method to delete the object.
   */
  virtual CORBA::Object_ptr create_object (
      const char * type_id,
      const PortableGroup::Criteria & the_criteria,
      PortableGroup::GenericFactory::FactoryCreationId_out
        factory_creation_id
      ACE_ENV_ARG_DECL_WITH_DEFAULTS)
    ACE_THROW_SPEC ((CORBA::SystemException,
                     PortableGroup::NoFactory,
                     PortableGroup::ObjectNotCreated,
                     PortableGroup::InvalidCriteria,
                     PortableGroup::InvalidProperty,
                     PortableGroup::CannotMeetCriteria));

  /**
   * Delete the object corresponding to the provided
   * FactoryCreationId.  If the object is actually an ObjectGroup,
   * then all members within the ObjectGroup will be deleted.
   * Afterward, the ObjectGroup itself will be deleted.
   */
  virtual void delete_object (
      const PortableGroup::GenericFactory::FactoryCreationId &
        factory_creation_id
      ACE_ENV_ARG_DECL_WITH_DEFAULTS)
    ACE_THROW_SPEC ((CORBA::SystemException,
                     PortableGroup::ObjectNotFound));

  //@}

  /// Return the next member to which client requests will be
  /// forwarded.
  /**
   * Select the next member of the object group corresponding to the
   * given ObjectId.  The object group's load balancing strategy
   * will be queried for that member.
   */
  CORBA::Object_ptr next_member (const PortableServer::ObjectId & oid
                                 ACE_ENV_ARG_DECL);

public:

  /// Initialize the load balancer.  This will cause a child POA to be
  /// created with the appropriate policies to support ServantLocators
  /// (i.e. for the MemberLocator).
  void init (ACE_Reactor * reactor,
             CORBA::ORB_ptr orb,
             PortableServer::POA_ptr root_poa
             ACE_ENV_ARG_DECL);

protected:

  /// Destructor.
  /**
   * Destructor is protected to enforce correct memory management
   * through reference counting.
   */
  ~TAO_LB_LoadManager (void);

private:

  /// Extract the value of the InitialNumberReplicas property from
  /// the_criteria.
  int get_initial_number_replicas (
    const char * type_id,
    const PortableGroup::Criteria & the_criteria,
    CORBA::UShort & initial_number_replicas) const;

  /// Extract the value of the Factories property from the_criteria.
  /**
   * This method ensures that the locations in the returned
   * FactoryInfos are unique.  This is necessary to ensure that only
   * one replica of a given type is created by the load balancer at a
   * given location.
   */
  int get_factory_infos (
    const char * type_id,
    const PortableGroup::Criteria & the_criteria,
    PortableGroup::FactoryInfos & factory_infos) const;

  /// Preprocess Strategy or CustomStrategy properties.
  /**
   * This method takes care of converting StrategyInfo properties to
   * Strategy properties, and verifying that CustomStrategy references
   * are not nil.
   */
  void preprocess_properties (PortableGroup::Properties & props
                              ACE_ENV_ARG_DECL);

  /// Create a built-in load balancing strategy and return a reference
  /// to it.
  CosLoadBalancing::Strategy_ptr make_strategy (
    CosLoadBalancing::StrategyInfo * info
    ACE_ENV_ARG_DECL);

private:

  /// Reactor used when pulling loads from registered load monitors.
  ACE_Reactor * reactor_;

  /// The POA that dispatches requests to the MemberLocator.
  PortableServer::POA_var poa_;

  /// The Root POA.
  PortableServer::POA_var root_poa_;

  /// Mutex that provides synchronization for the LoadMonitor map.
  TAO_SYNCH_MUTEX monitor_lock_;

  /// Mutex that provides synchronization for the LoadMap table.
  TAO_SYNCH_MUTEX load_lock_;

  /// Mutex that provides synchronization for the LoadAlert table.
  TAO_SYNCH_MUTEX load_alert_lock_;

  /// Mutex that provides synchronization for the LoadManager's
  /// state.
  TAO_SYNCH_MUTEX lock_;

  /// Table that maps PortableGroup::Location to load monitor at that
  /// location.
  TAO_LB_MonitorMap monitor_map_;

  /// Table that maps location to load list.
  TAO_LB_LoadListMap load_map_;

  /// Table that maps object group and location to LoadAlert object.
  TAO_LB_LoadAlertMap load_alert_map_;

  /// The ObjectGroupManager that implements the functionality
  /// necessary for application-controlled object group membership.
  TAO_PG_ObjectGroupManager object_group_manager_;

  /// The PropertyManager that is reponsible for parsing all criteria,
  /// and keeping track of property-type_id associations.
  TAO_PG_PropertyManager property_manager_;

  /// The GenericFactory responsible for creating all object groups.
  TAO_PG_GenericFactory generic_factory_;

  /// The event handler that performs "pull monitoring" on all
  /// registered load monitors.
  TAO_LB_Pull_Handler pull_handler_;

  /// Timer ID corresponding to the timer that fires off the "pull
  /// monitoring" event handler.
  long timer_id_;

  /// Cached object reference that points to this servant.
  CosLoadBalancing::LoadManager_var lm_ref_;

  /// Cached object reference that points to the AMI handler for all
  /// LoadAlert objects.
  CosLoadBalancing::AMI_LoadAlertHandler_var load_alert_handler_;

  /**
   * @name Built-in load balancing strategy implementations
   *
   * "Built-in" load balancing strategies defined by the load
   * balancing specification.
   */
  //@{
  /// The "RoundRobin" load balancing strategy.
  CosLoadBalancing::Strategy_var round_robin_;

  /// The "Random" load balancing strategy.
  CosLoadBalancing::Strategy_var random_;

  /// The "LeastLoaded" load balancing strategy.
  CosLoadBalancing::Strategy_var least_loaded_;
  //@}

  /// Cached instance of the Property name
  /// "org.omg.CosLoadBalancing.StrategyInfo".
  PortableGroup::Name built_in_balancing_strategy_info_name_;

  /// Cached instance of the Property name
  /// "org.omg.CosLoadBalancing.Strategy".
  PortableGroup::Name built_in_balancing_strategy_name_;

  /// Cached instance of the Property name
  /// "org.omg.CosLoadBalancing.CustomStrategy".
  PortableGroup::Name custom_balancing_strategy_name_;

};


#include /**/ "ace/post.h"

#endif  /* TAO_LB_LOAD_MANAGER_H */