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+// -*- C++ -*-
+
+//=============================================================================
+/**
+ *  @file LB_LeastLoaded.h
+ *
+ *  $Id$
+ *
+ *  @author Ossama Othman <ossama@uci.edu>
+ */
+//=============================================================================
+
+
+#ifndef LB_LEAST_LOADED_H
+#define LB_LEAST_LOADED_H
+
+#include /**/ "ace/pre.h"
+
+#include "orbsvcs/LoadBalancing/LB_LoadMap.h"
+
+# if !defined (ACE_LACKS_PRAGMA_ONCE)
+#   pragma once
+# endif /* ACE_LACKS_PRAGMA_ONCE */
+
+#include "orbsvcs/CosLoadBalancingS.h"
+
+#include "ace/Synch_Traits.h"
+#include "ace/Thread_Mutex.h"
+
+TAO_BEGIN_VERSIONED_NAMESPACE_DECL
+
+namespace TAO_LB
+{
+  /**
+   * @name Default LeastLoaded strategy parameters.
+   *
+   * Defaults defined by the Load Balancing specification.
+   */
+  //@{
+  const CORBA::Float LL_DEFAULT_CRITICAL_THRESHOLD = 0;
+  const CORBA::Float LL_DEFAULT_REJECT_THRESHOLD = 0;
+  const CORBA::Float LL_DEFAULT_TOLERANCE = 1;
+  const CORBA::Float LL_DEFAULT_DAMPENING = 0;
+  const CORBA::Float LL_DEFAULT_PER_BALANCE_LOAD = 0;
+  //@}
+
+  /**
+   * @name TAO-specific LeastLoaded strategy parameters.
+   *
+   * Parameters internal to TAO's LeastLoaded strategy
+   * implementation.
+   */
+  //@{
+  /// Percentage difference between two load values that determines
+  /// whether the loads are considered equivalent.
+  /**
+   * If the percent difference between two loads, i.e.:
+   *   (Old Load - New Load) / New Load
+   * is less than or equal to this value, the two loads will be
+   * considered equivalent.  In such a case, an object group member
+   * residing at the location corresponding to one of the two loads
+   * will be selected at random.
+   */
+  const CORBA::Float LL_DEFAULT_LOAD_PERCENT_DIFF_CUTOFF = 0.01f;  // 1%
+  //@}
+}
+
+/**
+ * @class TAO_LB_LeastLoaded
+ *
+ * @brief "Least loaded" load balancing strategy
+ *
+ * This load balancing strategy is designed to select an object group
+ * member residing at a location with the smallest load.
+ */
+class TAO_LB_LeastLoaded
+  : public virtual POA_CosLoadBalancing::Strategy
+{
+public:
+
+  /// Constructor.
+  TAO_LB_LeastLoaded (PortableServer::POA_ptr poa);
+
+  /**
+   * @name CosLoadBalancing::Strategy methods
+   *
+   * Methods required by the CosLoadBalancing::Strategy interface.
+   */
+  //@{
+  virtual char * name (void);
+
+  virtual CosLoadBalancing::Properties * get_properties ();
+
+  virtual void push_loads (
+      const PortableGroup::Location & the_location,
+      const CosLoadBalancing::LoadList & loads);
+
+  virtual CosLoadBalancing::LoadList * get_loads (
+      CosLoadBalancing::LoadManager_ptr load_manager,
+      const PortableGroup::Location & the_location);
+
+  virtual CORBA::Object_ptr next_member (
+      PortableGroup::ObjectGroup_ptr object_group,
+      CosLoadBalancing::LoadManager_ptr load_manager);
+
+  virtual void analyze_loads (
+      PortableGroup::ObjectGroup_ptr object_group,
+      CosLoadBalancing::LoadManager_ptr load_manager);
+  //@}
+
+  /// Returns the default POA for this servant.
+  virtual PortableServer::POA_ptr _default_POA (
+    );
+
+  /// Initialize the LeastLoaded instance with the given properties.
+  void init (const PortableGroup::Properties & props);
+
+protected:
+
+  /// Destructor.
+  ~TAO_LB_LeastLoaded (void);
+
+  /// Retrieve the least loaded location from the given list of
+  /// locations.
+  CORBA::Boolean get_location (CosLoadBalancing::LoadManager_ptr load_manager,
+                               const PortableGroup::Locations & locations,
+                               PortableGroup::Location & location);
+
+  /// Return the effective load.
+  CORBA::Float effective_load (CORBA::Float previous_load,
+                               CORBA::Float new_load);
+
+  /// Push the new load into this Strategy's load processor, and
+  /// return the corresponding effective load.
+  void push_loads (
+      const PortableGroup::Location & the_location,
+      const CosLoadBalancing::LoadList & loads,
+      CosLoadBalancing::Load & effective_load);
+
+  /// Utility method to extract a CORBA::Float value from the given
+  /// property.
+  void extract_float_property (const PortableGroup::Property & property,
+                               CORBA::Float & value);
+
+private:
+
+  /// This servant's default POA.
+  PortableServer::POA_var poa_;
+
+  /// Table that maps location to load list.
+  TAO_LB_LoadMap * load_map_;
+
+  /// Lock used to ensure atomic access to state retained by this
+  /// class.
+  TAO_SYNCH_MUTEX * lock_;
+
+  /// Cached set of properties used when initializing this strategy.
+  CosLoadBalancing::Properties properties_;
+
+  /**
+   * @name LeastLoaded Property Values
+   *
+   * Cached LeastLoaded load balancing strategy property values.
+   */
+  //@{
+
+  /// The critical load threshold.
+  /**
+   * Load rebalancing/shedding will occur if loads at a given location
+   * are greater than this value.  The default value is zero, which
+   * indicates that no load rebalancing/shedding will occur.
+   */
+  CORBA::Float critical_threshold_;
+
+  /// The request rejection threshold.
+  /**
+   * If the load at a given location is greater than this value, the
+   * member at that location will not be considered when choosing a
+   * member to the request will be forwarded.  If all locations have
+   * loads greater than this value, a @c CORBA::TRANSIENT exception
+   * will be thrown unless the reject threshold is zero, which is the
+   * default.  If the request rejection threshold is zero, a @c
+   * CORBA::TRANSIENT will not be thrown by this load balancing
+   * strategy, unless no object group members have been added yet.
+   */
+  CORBA::Float reject_threshold_;
+
+  ///
+  CORBA::Float tolerance_;
+
+  ///
+  CORBA::Float dampening_;
+
+  ///
+  CORBA::Float per_balance_load_;
+
+  //@}
+
+};
+
+TAO_END_VERSIONED_NAMESPACE_DECL
+
+
+#if defined (__ACE_INLINE__)
+#include "orbsvcs/LoadBalancing/LB_LeastLoaded.inl"
+#endif /* defined INLINE */
+
+#include /**/ "ace/post.h"
+
+#endif  /* LB_LEAST_LOADED_H */