// src/backend/policy_manager.hh - Copyright 2005, 2006, University
//               of Padova, dept. of Pure and Applied
//               Mathematics
//
// This file is part of SGPEMv2.
//
// This 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.
//
// SGPEMv2 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 SGPEMv2; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

#ifndef POLICY_MANAGER_HH
#define POLICY_MANAGER_HH 1

#include "config.h"

#include "policy.hh"


namespace sgpem
{
    class PolicyManager;
    
  /**
    PolicyManager is the Abstract Factory for \ref Policy objects.
  */
    class SG_DLLEXPORT PolicyManager
    {
    public:  
        /** \brief PolicyManager constructor 
         *
	 * Saves ``this'' pointer into the _registered attribute, so it can access
	 * it when requested. This is done so that concrete subclasses can be defined
	 * even if they are found in external dynamic modules not known at compile time.
	 *
	 * For the moment, just an instance of PolicyManager can be saved. This will
	 * be expanded in next milestones.
	 */
        PolicyManager();

	virtual ~PolicyManager() = 0;

	/**
	 Gets THE policy (the only today) used.
	 Next versions will implement some other kind.
	 \return A reference to the policy.
	 */
	virtual Policy&		get_policy() = 0;

	/**
	 Init (or reset if yet initialized) the manager.
	 */
	virtual void		init() = 0;

	/** \brief Get the registered manager instance
	 *
	 * \return The registered policy manager instance.
	 */
	static PolicyManager& get_registered_manager();

    private:
	/** A pointer to the registered instance */
	static PolicyManager* _registered;
    };
    
} //~ namespace sgpem

#endif