Resource.hh

//********************************************************************
//*** ResourcePool/SQL/Resource.hh
//*** Copyright (c) 2003-2009 by Markus Winand <mws@fatalmind.com>
//*** $Id: Resource.hh,v 1.10 2009-03-02 14:16:45 mws Exp $
//********************************************************************
/*
This file is part of ResourcePool.

ResourcePool 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.

ResourcePool 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 ResourcePool; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307  USA */

#ifndef RESOURCEPOOL_SQL_RESOURCE_HH
#define RESOURCEPOOL_SQL_RESOURCE_HH

#include "mm/gc_ptr.hh"

#include "ResourcePool/Resource.hh"
#include "ResourcePool/Command.hh"
#include "ResourcePool/SQL/ResourcePoolFwd.hh"

#include <string>

namespace fatalmind {
namespace SQL {

/*
 * A Resource implementation to access SQL databases.
 */
template<class TM>
class SQLResource
: public fatalmind::Resource
{
    public:
        SQLResource();
        virtual ~SQLResource();

        virtual bool precheck() = 0;
        virtual bool postcheck() = 0;
        virtual void close() = 0;
        virtual void fail_close() = 0;

        SQLResource<TM>& get_plain_resource() {
            return *this;
        };

        /*
         * Returns a string describing the identiy of the database session.
         * Intended for human usage to perform administrative actions upon the session.
         */
        virtual const std::string& getSessionID() const = 0;
};

template<class TM>
class DummySQLResource: public SQLResource<TM> {
    public:
        DummySQLResource();
};

template<class TM, class RT>
class SQLResourceSpecialized
: public DummySQLResource<TM>
{
        typedef gc_ptr<RT> ptr_t;
    public:
        SQLResourceSpecialized(RT* a_resource);
        SQLResourceSpecialized(RT& a_resource);

        virtual ~SQLResourceSpecialized();

        virtual bool precheck();
        virtual bool postcheck();
        virtual void close();
        virtual void fail_close();
        
        RT& getRealResource() const {
            return resource_ref;
        };      
            
        const std::string& getSessionID() const;
        const std::string& getResourceID() const;

    private:
        ptr_t resource_;
        RT&   resource_ref;
};

} // namespace SQL
} // namespace fatalmind

#endif

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