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ACE_Dynamic_Service_Dependency Class Reference

Provides a way to declare dependency on specific service, thus helping to avoid order of initialization issues with instances of an objects whose implementation code resides in dynamically loaded services. More...

#include <Dynamic_Service_Dependency.h>

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Public Member Functions

 ACE_Dynamic_Service_Dependency (const ACE_Service_Gestalt *cfg, const ACE_TCHAR *principal)
 ACE_Dynamic_Service_Dependency (const ACE_TCHAR *principal)
 ~ACE_Dynamic_Service_Dependency (void)

Private Member Functions

void init (const ACE_Service_Gestalt *cfg, const ACE_TCHAR *principal)

Private Attributes

ACE_DLL tracker_

Detailed Description

Provides a way to declare dependency on specific service, thus helping to avoid order of initialization issues with instances of an objects whose implementation code resides in dynamically loaded services.

It is disastrous to have dynamically loadable services create and give away ownership of objects and then ending up being unloaded before all those instances have been deleted. Normally the code for such objects classes resides within the TEXT segment of the DLL, which implements the service. If a service gets removed, its DLL may be unmapped from memory and then any attempt to invoke a method on the said objects will cause SEGV.

Such instances must contain a member of ACE_Dynamic_Service_Dependency initialized with the service they depend on. ACE_Dynamic_Service_Dependency's constructor and destructor are "magical" - they work by maintaining the underlying dynamic service's DLL reference count.

Definition at line 50 of file Dynamic_Service_Dependency.h.

Constructor & Destructor Documentation

ACE_Dynamic_Service_Dependency::ACE_Dynamic_Service_Dependency (  const ACE_Service_Gestalt *  cfg,
const ACE_TCHAR *  principal
) 
 

Definition at line 20 of file Dynamic_Service_Dependency.cpp.

References ACE_TCHAR, and init(). 

00022 {
00023   this->init (cfg, principal);
00024 }

ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_Dynamic_Service_Dependency::ACE_Dynamic_Service_Dependency (  const ACE_TCHAR *  principal  ) 
 

Definition at line 15 of file Dynamic_Service_Dependency.cpp.

References ACE_TCHAR, and init(). 

00016 {
00017   this->init (ACE_Service_Config::current (), principal);
00018 }

ACE_Dynamic_Service_Dependency::~ACE_Dynamic_Service_Dependency (  void   ) 
 

Definition at line 27 of file Dynamic_Service_Dependency.cpp.

References ACE_DEBUG, ACE_TEXT, ACE::debug(), and LM_DEBUG. 

00028 {
00029   if (ACE::debug ())
00030     ACE_DEBUG ((LM_DEBUG,
00031                 ACE_TEXT ("(%P|%t) DSD, this=%@ - destroying\n"),
00032                 this));
00033 }

Member Function Documentation

void ACE_Dynamic_Service_Dependency::init (  const ACE_Service_Gestalt *  cfg,
const ACE_TCHAR *  principal
)  [private]
 

Definition at line 36 of file Dynamic_Service_Dependency.cpp.

References ACE_DEBUG, ACE_TCHAR, ACE_TEXT, ACE::debug(), ACE_Service_Type::dll(), ACE_Service_Type::dump(), ACE_Dynamic_Service_Base::find_i(), LM_DEBUG, and tracker_.

Referenced by ACE_Dynamic_Service_Dependency(). 

00038 {
00039   const ACE_Service_Type* st =
00040     ACE_Dynamic_Service_Base::find_i (cfg, principal,false);
00041   if (ACE::debug ())
00042     {
00043       ACE_DEBUG ((LM_DEBUG,
00044       ACE_TEXT ("(%P|%t) DSD, this=%@ - creating dependency on "), this));
00045       st->dump ();
00046     }
00047   this->tracker_ = st->dll ();
00048 }

Member Data Documentation

ACE_DLL ACE_Dynamic_Service_Dependency::tracker_ [private]
 

Definition at line 62 of file Dynamic_Service_Dependency.h.

Referenced by init().

The documentation for this class was generated from the following files:
Generated on Sun Jan 27 12:54:35 2008 for ACE by doxygen 1.3.6