/* -*- mode: c++ -*- 
*/
/* 

    GIFT, a flexible content based image retrieval system.
    Copyright (C) 1998, 1999, 2000 CUI, University of Geneva

    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; either version 2 of the License, or
    (at your option) any later version.

    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.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/
// -*- mode: c++ -*-
#ifndef _CACCESSORFACTORYCONTAINER
#define _CACCESSORFACTORYCONTAINER

#include <map>
#include <string>
#include "CSelfDestroyPointer.h"
class CXMLElement;
class CAccessor;
class CAccessorFactory;
/**
 * This is destined to hold a number of CAccessorFactories.
 * The use of this is to have an open-close-counter for 
 * all the factories which have been registered in this
 * 
 * New elements are only constructed if necessary.
 *
 *@author Wolfgang Müller
 */
class CAccessorFactoryContainer{
  /** 
      This tree contains the configuration data for this
  */
  CSelfDestroyPointer<CXMLElement> mConfigurationData;
  class CContentElement{
  public:
    /** Contains a pointer to the accessor, if already opened */
    CAccessorFactory* mFactory;
    /** Counts how often the accessor has been opened or closed */
    int mOpenCloseCounter;
  };
  /** 
      Typedef: The content is a map of string to content element 
      In this map is noted, which accessors are open for the
      collection with the given ID.
   */
public:
  typedef map<string,CContentElement> CContent;
protected:
  /** the content */
  CContent mContent;
     
 public:
  /** construct this. In the case of static linking,
      this means the construction of factorys
      for all accessors.
  */
  CAccessorFactoryContainer();
  /** configure this

      In the case of dynamic linking we will scan
      libdir for plugins
   */
  void configure(CXMLElement* inConfigurationData);
  /**
     The destructor destroys the CContentElements properly 
  */
  ~CAccessorFactoryContainer();
  /** 
      adding a factory to the content
   */
  void registerFactory(CAccessorFactory* inFactory,
		       string inName);
  /**
     opening an accessor:
     if the accessor is already constructed,
     then simply give the pointer,
     otherwhise construct a new one 
     using the appropriate factory

     @param name of the accessor to be created
     @param inConfigurationData the configuration data of 
            the CXMLElement to be created
  */
  CAccessor* openAccessor(string inName,
			  const CXMLElement& inCollectionElement);
  /**
     closing an accessor.
     If there have been as many openAccessor 
     as closeAccessor calls, the accessor will
     be delete-d.
  */
  void closeAccessor(string inName);
  
};

#endif
