ElementDatabase.h

Go to the documentation of this file.

/*

License

Menge
Copyright © and trademark ™ 2012-14 University of North Carolina at Chapel Hill. 
All rights reserved.

Permission to use, copy, modify, and distribute this software and its documentation 
for educational, research, and non-profit purposes, without fee, and without a 
written agreement is hereby granted, provided that the above copyright notice, 
this paragraph, and the following four paragraphs appear in all copies.

This software program and documentation are copyrighted by the University of North 
Carolina at Chapel Hill. The software program and documentation are supplied "as is," 
without any accompanying services from the University of North Carolina at Chapel 
Hill or the authors. The University of North Carolina at Chapel Hill and the 
authors do not warrant that the operation of the program will be uninterrupted 
or error-free. The end-user understands that the program was developed for research 
purposes and is advised not to rely exclusively on the program for any reason.

IN NO EVENT SHALL THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE AUTHORS 
BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL 
DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS 
DOCUMENTATION, EVEN IF THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL OR THE 
AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS SPECIFICALLY 
DISCLAIM ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND ANY STATUTORY WARRANTY 
OF NON-INFRINGEMENT. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND 
THE UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL AND THE AUTHORS HAVE NO OBLIGATIONS 
TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

Any questions or comments should be sent to the authors {menge,geom}@cs.unc.edu

*/

#ifndef __ELEMENT_DATABASE_H__
#define __ELEMENT_DATABASE_H__

#include <string>
#include <list>
#include "tinyxml.h"
#include "Logger.h"

namespace Menge {

    template < class Factory, class Element >
    class ElementDB {
    public:
        static inline size_t count() { return _factories.size(); }
        
        static Element * getInstance( TiXmlElement * node, const std::string & behaveFldr ) {
            // extract type name
            const char * typeCStr = node->Attribute( "type" );
            if ( ! typeCStr ) {
                logger << Logger::ERR_MSG << "A " << getElementName() << " tag has been provided with no \"type\" attribute on line " << node->Row() << "\n";
                return 0x0;
            }
            std::string typeName( typeCStr );
            typename std::list< Factory * >::iterator itr = _factories.begin();
            for ( ; itr != _factories.end(); ++itr ) {
                const Factory * factory = *itr;
                if ( factory->thisFactory( typeName ) ) {
                    // try to parse it
                    Element * element = factory->createInstance( node, behaveFldr );
                    if ( ! element ) {
                        logger << Logger::ERR_MSG << "The " << getElementName() << " of type \"" << typeName << "\" defined on line " << node->Row() << " could not be instantiated.\n";
                        return 0x0;
                    }
                    return element;
                }
            }

            logger << Logger::ERR_MSG << "Found an undefined " << getElementName() << " type (" << typeName << ") on line " << node->Row() << "\n";
            return 0x0;
        }

        static void initialize() {
            if ( ! _initialized ) {
                _initialized = true;
                addBuiltins();
            }
        }
        
        static void addBuiltins();
        
        static bool addFactory( Factory * factory ) {
            std::string testName( factory->name() );
            typename std::list< Factory * >::iterator itr = _factories.begin();
            for (; itr != _factories.end(); ++itr ) {
                std::string prevName( (*itr)->name() );
                if ( testName == prevName ) {
                    logger << Logger::ERR_MSG << "Trying to add a " << getElementName() << " factory which conflicts with a previous condition factories.\n";
                    logger << "\tBoth " << getElementName() << "s use the name: " << testName << ".\n";
                    logger << "\tDescription of the first " << getElementName() << " type: " << (*itr)->description() << ".\n";
                    logger << "\tDescription of the new " << getElementName() << " type: " << factory->description() << ".";
                    factory->destroy();
                    return false;
                }
            }
            _factories.push_back( factory );
            return true;
        }

        static std::string getElementName();
        
        static void clear() {
            typename std::list< Factory * >::iterator itr = _factories.begin();
            for ( ; itr != _factories.end(); ++itr ) {
                (*itr)->destroy();
            }
            _factories.clear();
        }
    protected:
        static bool _initialized;
        
        static std::list< Factory * > _factories;
        
    };

    // The two functions, addBuiltins and getElementName are *not* defined in-line
    //  because of a quirk of visual studio's template system.  By defining the
    //  default functionality for the template OUTSIDE the class definition,
    //  these can be properly, explicitly specialized in separate C++ files.

    template < class Factory, class Element >
    void ElementDB< Factory, Element >::addBuiltins() {}

    template < class Factory, class Element >
    std::string ElementDB< Factory, Element >::getElementName(){ return "unnamed"; }

    template < class Factory, class Element >
    bool ElementDB< Factory, Element >::_initialized = false;

    template < class Factory, class Element >
    std::list< Factory * > ElementDB< Factory, Element >::_factories;
}   // namespace Menge

#endif  // __ELEMENT_DATABASE_H__