TAO/tao/DLL_Parser.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file   DLL_Parser.h
   6  *
   7  *  @author Carlos O'Ryan (coryan@cs.wustl.edu)
   8  */
   9 //=============================================================================
  10
  11 #ifndef TAO_DLL_PARSER_H
  12 #define TAO_DLL_PARSER_H
  13
  14 #include /**/ "ace/pre.h"
  15 #include "ace/Service_Config.h"
  16
  17 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  18 # pragma once
  19 #endif /* ACE_LACKS_PRAGMA_ONCE */
  20
  21 #include "tao/IOR_Parser.h"
  22
  23 #if (TAO_HAS_DDL_PARSER == 1)
  24
  25 TAO_BEGIN_VERSIONED_NAMESPACE_DECL
  26
  27 /**
  28  * @class TAO_DLL_Parser
  29  *
  30  * @brief Implment the parser for the DLL-style IORs.
  31  *
  32  * The DLL-style IORs allows applications to transparently load object
  33  * implementations. The ORB can parse an IOR in the format:
  34  *
  35  * DLL:Service_Name
  36  *
  37  * the string_to_object() function will use ACE's Service Configurator
  38  * framework to dynamically load the service named 'Service_Name'
  39  * using all the normal platform-independent naming conventions and
  40  * environment variable lookup rules that are normally used by @c
  41  * ACE_DLL::open().  The ORB assumes that this service implements the
  42  * TAO_Object_Loader interface, and uses that interface to create a
  43  * new object implementation locally. The object reference for this
  44  * local object is returned to the application.
  45  *
  46  * This can be used in applications that sometimes require local
  47  * object while other times they may use a remote implementation.
  48  * For example, the application could be configured to use a remote
  49  * Event Service or to dynamically load an Event Service
  50  * implementation and use the local copy instead.  The local Event
  51  * Service would federate to its remote peers to work as-if a single
  52  * Event Service was in place.
  53  *
  54  * Such an application could be written as follows:
  55  *
  56  * int main (int argc, char* argv)
  57  * {
  58  *   CORBA::ORB_var orb = CORBA::ORB_init(argc, argv);
  59  *
  60  *   CORBA::Object_var object =
  61  *     orb->resolve_initial_references("EventService");
  62  *   // Use <object> here...
  63  * }
  64  *
  65  * if the application is invoked using:
  66  *
  67  * $ program -ORBInitRef EventService=IOR:....
  68  *
  69  * then a remote event service is used, but the application could also
  70  * be invoked using:
  71  *
  72  * $ program -ORBInitRef EventService=DLL:Event_Service_Loader
  73  *
  74  * In this case the Event_Service implementation will be dynamically
  75  * loaded without any modifications to the application code.
  76  */
  77 class TAO_DLL_Parser : public TAO_IOR_Parser
  78 {
  79 public:
  80   TAO_DLL_Parser () = default;
  81   ~TAO_DLL_Parser () override = default;
  82
  83   // = The IOR_Parser methods, please read the documentation in
  84   //   IOR_Parser.h
  85   bool match_prefix (const char *ior_string) const override;
  86   CORBA::Object_ptr parse_string (const char *ior,
  87                                   CORBA::ORB_ptr orb) override;
  88 };
  89
  90 ACE_STATIC_SVC_DECLARE_EXPORT (TAO, TAO_DLL_Parser)
  91 ACE_FACTORY_DECLARE (TAO, TAO_DLL_Parser)
  92
  93 TAO_END_VERSIONED_NAMESPACE_DECL
  94
  95 #endif /* TAO_HAS_DDL_PARSER == 1 */
  96
  97 #include /**/ "ace/post.h"
  98 #endif /* TAO_DLL_PARSER_H */