DynamicPluggableFactory.cxx

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// $Id: DynamicPluggableFactory.cxx,v 1.8 2002/07/30 19:35:20 gmieg Exp $
//
// DynamicPluggableFactory.cxx
//
// Begin_Html<img src="../../pedestrians.gif" align=center>
// <a href="../source_warning.html">Warning for beginners</a>.<br> 
//
// DynamicPluggableFactory implements Dynamic Pluggable Factory Pattern.
// Adapted from "Pluggable Factory in Practice" by Anthony Lauder,
// C++ Report, October 1999, p. 27
//
// Author:  G. Irwin 10/2000
//
// Also see <a href="../../root_crib/index.html">The ROOT Crib</a> and 
// <a href="../DynamicFactory.html"> DynamicFactory Classes</a> (part of
// <a href="../index.html">The MINOS Class User Guide</a>)End_Html

#include <cassert>

#include "TClass.h"
#include "TROOT.h"
#include "TSystem.h"

#include "Algorithm/AlgConfig.h"
#include "DynamicFactory/DynAlgReg.h"
#include "DynamicFactory/DynamicPluggableFactory.h"
#include "MessageService/MsgService.h"

ClassImp(DynamicPluggableFactory)

// Define static variables.  They get initialized to zero by default.
  DynamicPluggableFactory *DynamicPluggableFactory::fsTheInstance;

//......................................................................
CVSID("$Id: DynamicPluggableFactory.cxx,v 1.8 2002/07/30 19:35:20 gmieg Exp $");

//______________________________________________________________________
DynamicPluggableFactory::DynamicPluggableFactory()
{
  MSG("DynFac", Msg::kDebug) << "DynamicPluggableFactory::Constructor\n";
  fsTheInstance = this;
}

//______________________________________________________________________
DynamicPluggableFactory::~DynamicPluggableFactory()
{
  MSG("DynFac", Msg::kDebug) << "DynamicPluggableFactory::Destructor\n";
  fDynamicAlgRegistry.Delete();
  fsTheInstance = 0;
}

//______________________________________________________________________
DynamicPluggableFactory &DynamicPluggableFactory::GetInstance()
{

// Cleaner destructor calls DynamicPluggableFactory dtor
   static Cleaner cleaner;

   if (!fsTheInstance) {
     MSG("DynFac", Msg::kDebug)
                    << "Instantiating DynamicPluggableFactory " << endl;
     cleaner.UseMe();           // dummy call to quiet compiler warnings
     fsTheInstance = new DynamicPluggableFactory();
   }
   return *fsTheInstance;
}

//______________________________________________________________________
AlgBase *DynamicPluggableFactory::GetPrototypicalAlg(const char *algnm)
{
  const TString algstr(algnm);
  DynAlgReg *dynalgfound = 0;

  TIter algregiter(&fDynamicAlgRegistry);
  DynAlgReg *dar;
  while ((dar = (DynAlgReg *) algregiter())) {
    if (dar->GetAlgName() == algstr) {
      dynalgfound = dar;
      break;
    }
  }

  if (!dynalgfound) return ((AlgBase *) 0);

// See if TUnixSystem knows about this Algorithm class yet.
  AlgBase *prototypicalalg = LinkPrototypicalAlg(algnm);

  if (prototypicalalg) {
    RegisterPrototypicalAlg(prototypicalalg);
    return prototypicalalg;
  }

// Need to link the dynamic library containing the Algorithm class.
  Int_t irc =
             gSystem->Load(dynalgfound->GetDynamicLibraryName().Data());
  if (irc < 0) {                                    // Library not found

    MSG("DynFac", Msg::kError)
      << "DynamicPluggableFactory::GetPrototypicalAlg(" << algnm << ")"
                                                 << ". Dynamic library "
     << dynalgfound->GetDynamicLibraryName().Data() <<  " not found.\n";

    return ((AlgBase *) 0);
  }
  
  prototypicalalg = LinkPrototypicalAlg(algnm);

  if (prototypicalalg) RegisterPrototypicalAlg(prototypicalalg);

  return prototypicalalg;
}

//______________________________________________________________________
AlgConfig *DynamicPluggableFactory::GetPrototypicalAlgConfig(
                                                      const char *regnm)
{
  const TString regstr(regnm);
  DynAlgReg *dynalgfound = 0;

  TIter algregiter(&fDynamicAlgRegistry);
  DynAlgReg *dar;
  while ((dar = (DynAlgReg *) algregiter())) {
    if (TString(dar->GetName()) == regstr) {
      dynalgfound = dar;
      break;
    }
  }

  if (!dynalgfound) return ((AlgConfig *) 0);

// See if TUnixSystem knows about this AlgConfig class yet.
  const char *cclnm = dar->GetAlgConfigName();             // ClassName
  AlgConfig *prototypicalalgconfig = LinkPrototypicalAlgConfig(cclnm);

  if (prototypicalalgconfig) {
    prototypicalalgconfig->SetName(regnm);
    RegisterPrototypicalAlgConfig(prototypicalalgconfig);
    return prototypicalalgconfig;
  }

// Need to link the dynamic library containing the Algorithm class.
  Int_t irc =
             gSystem->Load(dynalgfound->GetDynamicLibraryName().Data());
  if (irc < 0) {                                    // Library not found

    MSG("DynFac", Msg::kError)
      << "DynamicPluggableFactory::GetPrototypicalAlgConfig("
                                 << regnm << ")" << ". Dynamic library "
     << dynalgfound->GetDynamicLibraryName().Data() <<  " not found.\n";

    return ((AlgConfig *) 0);
  }
  
  prototypicalalgconfig = LinkPrototypicalAlgConfig(cclnm);

  if (prototypicalalgconfig) {
    prototypicalalgconfig->SetName(regnm);
    RegisterPrototypicalAlgConfig(prototypicalalgconfig);
  }

  return prototypicalalgconfig;
}

//______________________________________________________________________
Bool_t DynamicPluggableFactory::IsRegistered(const char *regnm) const
{

  return (fDynamicAlgRegistry.FindObject(regnm) != 0);

}

//______________________________________________________________________
AlgBase &DynamicPluggableFactory::LendAlg(const char *algnm)
{
  AlgBase *algbase = GetAlgPtr(algnm);

  if (!algbase) {
    AlgBase *prototypicalalg = GetPrototypicalAlg(algnm);
    algbase = (prototypicalalg ? prototypicalalg : 0);
    if (!algbase) {
    MSG("DynFac", Msg::kError)
                  << "DynamicPluggableFactory::LendAlg(" << algnm << ")"
          << ":  Prototypical Algorithm not found.  Abort job." << endl;
    }
    assert(algbase);
  }

  return *algbase;
}

//______________________________________________________________________
AlgConfig &DynamicPluggableFactory::LendAlgConfig(const char *regnm)
{
  AlgConfig *algconfig = GetAlgConfigPtr(regnm);

  if (!algconfig) {
    AlgConfig *prototypicalalgconfig = GetPrototypicalAlgConfig(regnm);
    algconfig = (prototypicalalgconfig ? prototypicalalgconfig : 0);
    if (!algconfig) {
    MSG("DynFac", Msg::kError)
           << "DynamicPluggableFactory::LendAlgConfig(" << regnm << ")"
         << ":  Prototypical AlgConfig not found.  Abort job." << endl;
    }
    assert(algconfig);
  }

  return *algconfig;
}

//______________________________________________________________________
AlgBase *DynamicPluggableFactory::LinkPrototypicalAlg(const char *algnm)
{
  MSG("DynFac", Msg::kDebug)
   << "DynamicPluggableFactory::LinkPrototypicalAlg(" << algnm << ")\n";

  AlgBase *prototypicalalg = 0;
  if (gROOT->GetClass(algnm,kTRUE))
    prototypicalalg = (AlgBase *) gROOT->GetClass(algnm,kTRUE)->New();

  return prototypicalalg ? prototypicalalg : 0;
}

//______________________________________________________________________
AlgConfig *DynamicPluggableFactory::LinkPrototypicalAlgConfig(
                                                      const char *cclnm)
{
  MSG("DynFac", Msg::kDebug)
   << "DynamicPluggableFactory::LinkPrototypicalAlg(" << cclnm << ")\n";

  AlgConfig *prototypicalalgconfig = 0;
  if (gROOT->GetClass(cclnm,kTRUE))
    prototypicalalgconfig =
                      (AlgConfig *) gROOT->GetClass(cclnm,kTRUE)->New();

  return prototypicalalgconfig ? prototypicalalgconfig : 0;
}

//______________________________________________________________________
void DynamicPluggableFactory::Register(DynAlgReg *dar)
{
  fDynamicAlgRegistry.Add(dar);
}

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