ossimFactoryBaseTemplate.h

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//*******************************************************************
//
// License:  See top level LICENSE.txt file.
//
// DESCRIPTION:
//   Contains declaration of template class ossimFactory. This is the base
//   type for all factories.
//
// SOFTWARE HISTORY:
//>
//   14Jun2001  Oscar Kramer (okramer@imagelinks.com)
//              Initial coding.
//<
//*****************************************************************************
//  $Id: ossimFactoryBaseTemplate.h 14799 2009-06-30 08:54:44Z dburken $

#ifndef ossimFactory_HEADER
#define ossimFactory_HEADER
#include <ossim/base/ossimConstants.h>
#include <list>

class ossimKeywordlist;
class ossimString;

/*!****************************************************************************
 *
 * TEMPLATE: ossimFactoryBase  
 *
 * NOTE: This is primarily intended as an interface template only to insure
 *       that all factories prescribe to a common type. Concrete classes shall
 *       be derived from an instance of this template as:
 *
 *       class MyFactory : public ossimFactoryBase<MyProductClass>
 *
 *       where MyProductClass is the class type being produced.
 *
 *       This template is applicable to "Registry" type factories that have
 *       one or more sub-factories. Thus, a common interface is provided
 *       without the client distinguishing between registries and factories.
 *
 * EXAMPLE: Refer to the projection factories for a working example of the
 *       use of this base class template. Specifically, refer to the files:
 *          - ../ossim_core/projections/factory/ossimProjectionFactory.h
 *          - ../ossim_core/projections/factory/ossimMapProjectionFactory.h
 *          - ../ossim_core/projections/factory/ossimSensorModelFactory.h
 *
 *****************************************************************************/
template <class Product> class OSSIMDLLEXPORT ossimFactoryBase 
{
public:
   virtual Product* create(const ossimString&)     const = 0;
   virtual Product* create(const ossimKeywordlist& kwl,
                           const char* prefix)          const = 0;

   virtual std::list<ossimString> getList() const = 0;

   void registerFactory(ossimFactoryBase<Product>* new_factory)
      { if(new_factory) theRegistry.push_back(new_factory); }
   
protected:
   ossimFactoryBase() {};

   virtual ~ossimFactoryBase() {}

   std::list<ossimFactoryBase<Product>*> theRegistry;
   
};

#endif