pluginiter.h

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/**********************************************************************
pluginiter.h - facilitates construction of plugin classes
 
Copyright (C) 2006 by Chris Morley
 
This file is part of the Open Babel project.
For more information, see <http://openbabel.sourceforge.net/>
 
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation version 2 of the License.
 
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.
***********************************************************************/

#ifndef OB_PLUGINITER_H
#define OB_PLUGINITER_H

#include <openbabel/babelconfig.h>

namespace OpenBabel
{

template<typename T>
class OBAPI PluginIter
{
private:
  typedef std::map<const std::string, T*> Maptype;
  Maptype _map;
  typename Maptype::iterator _itr;
  T* _default;

public:
  void Register(T* pType, const std::string ID, bool IsDefault)
  {
    _map[ID] = pType;
    if(IsDefault || _map.empty())
      _default=pType;
  }

  T* FindType(const std::string& ID)
  {
    if(ID.empty())
      return _default;
    _itr = _map.find(ID);
    if(_itr==_map.end())
      return NULL;
    else
      return _itr->second;
  }

  T* FindDefaultType() const { return _default; }

  std::string ID() const { return _itr->first; }
  

//The following function and operator* cause an linking error with SWIG,
//perhaps because they are not used in the C++ code and, being templated,
//are consequently not generated by the compiler. Temporarily they have been
//commented out.

//  std::string Description() const { return _itr->second->Description(); }



  void ToStart() { _itr = _map.begin(); }
  
  PluginIter& operator++()
  {
    ++_itr;
    return *this;
  }
  operator bool() const { return _itr != _map.end(); }
  T* operator->() const   { return _itr->second;  }
//  T& operator*() const    { return *(_itr->second); }
};

//Macro to iterate over all sub-types
#define FOR_EACH(plugintype, f)  for(PluginIter<plugintype>& f=plugintype::Iter(); f; ++f )

//Macro to be added to definition of the base class
#define MAKE_PLUGIN(BaseClass)\
public:\
BaseClass(std::string ID, bool IsDefault=false)\
{Iter().Register(this, ID, IsDefault);}\
static PluginIter<BaseClass>& Iter()\
{static PluginIter<BaseClass>* p = NULL;\
if(!p) p = new PluginIter<BaseClass>;\
p->ToStart();\
return *p;}\
static BaseClass* FindDefaultType(){ return Iter().FindDefaultType();}\
  static BaseClass* FindType(const std::string& ID){ return Iter().FindType(ID);}

} //namespace
#endif //OB_PLUGINITER_H

---

This file is part of the documentation for Open Babel, version 2.1.0.

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