TAO/tests/POA/On_Demand_Loading/Servant_Manager.h

   1 //=============================================================================
   2 /**
   3  *  @file     Servant_Manager.h
   4  *
   5  *   Helper class for <ServantActivator_i> and <ServantLoactor_i>.
   6  *
   7  *  @author  Kirthika Parameswaran <kirthika@cs.wustl.edu>
   8  */
   9 //=============================================================================
  10
  11 #ifndef SERVANT_MANAGER_H
  12 #define SERVANT_MANAGER_H
  13
  14 #include "ace/DLL.h"
  15 #include "ace/Containers.h"
  16
  17 #include "tao/PortableServer/PortableServer.h"
  18 #include "tao/PortableServer/Servant_Base.h"
  19 #include "tao/PortableServer/Active_Object_Map.h"
  20
  21 #include "tao/ORB.h"
  22 #include "ace/SString.h"
  23
  24 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  25 # pragma once
  26 #endif /* ACE_LACKS_PRAGMA_ONCE */
  27
  28 /**
  29  * @class ServantManager_i
  30  *
  31  * @brief This class is the helper class for the ServantActivator_i and
  32  * ServantLocator_i classes.
  33  *
  34  * The methods provided by this class are used by the ServantActivator_i
  35  * and ServantLocator_i classes. This class contains the common methods
  36  * needed by them.
  37  */
  38 class ServantManager_i
  39 {
  40 public:
  41   /// This typedef is used to typecast the void* obtained when finding
  42   /// a symbol in the DLL.
  43    typedef PortableServer::Servant
  44            (*SERVANT_FACTORY) (CORBA::ORB_ptr orb,
  45                                PortableServer::POA_ptr poa);
  46
  47   /// Initialization.
  48   ServantManager_i (CORBA::ORB_ptr orb);
  49
  50   /// Destruction.
  51    ~ServantManager_i ();
  52
  53   /**
  54    * Returns an ObjectId when given an DLL name and the factory method
  55    * to be invoked in the DLL. The application developer can initialise the
  56    * ServantActivator object by providing the dllname and the factory function.
  57    */
  58   PortableServer::ObjectId_var create_dll_object_id (const char *libname,
  59                                                      const char *factory_function);
  60
  61   // @@ *done*Kirthika, please explain what this function is USED for, i.e.,
  62   // who calls it and why?
  63
  64   /**
  65    * Obtains a servant on activation by linking and loading the
  66    * appropriate DLL and creating the servant object.  The <str>
  67    * argument is the ObjectId that contains the servant DLL name and
  68    * the factory function name. The <long> argument is an
  69    * servant-specific argument needed to create the servant for this
  70    * particular use-case.
  71    */
  72   PortableServer::Servant obtain_servant (const ACE_TCHAR *str,
  73                                           PortableServer::POA_ptr poa);
  74
  75   /// The servant is destroyed and the DLL that was dynamically linked
  76   /// is closed.
  77   void destroy_servant (PortableServer::Servant servant,
  78                         const PortableServer::ObjectId &oid);
  79
  80  private:
  81   /**
  82    * Parse the string to obtain the DLL name and the factory function
  83    * symbol that we will used to dynamically obtain the servant
  84    * pointer.
  85    */
  86   void parse_string (const ACE_TCHAR *s);
  87
  88   /// A reference to the ORB.
  89   CORBA::ORB_var orb_;
  90
  91   /// The name of the dll containing the servant.
  92   ACE_TString dllname_;
  93
  94   /// The symbol which on getting invoked will give us the servant
  95   /// pointer.
  96   ACE_TString create_symbol_;
  97
  98   typedef ACE_Hash_Map_Manager_Ex<PortableServer::ObjectId,
  99                                   ACE_DLL *,
 100                                   TAO_ObjectId_Hash,
 101                                   ACE_Equal_To<PortableServer::ObjectId>,
 102                                   ACE_Null_Mutex>
 103           SERVANT_MAP;
 104
 105   /**
 106    * This is the hash map object. The hash map is used to provide
 107    * an quick access to the dll object associated with every servant
 108    * using the unique ObjectId as key.
 109    */
 110   SERVANT_MAP servant_map_;
 111 };
 112 #endif /* SERVANT_MANAGER_H */