src/utils/GenericFactory.hpp

/*
 * Copyright (C) 2000-2004  Object Oriented Parallel Simulation Engine (OOPSE) project
 * 
 * Contact: oopse@oopse.org
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 * All we ask is that proper credit is given for our work, which includes
 * - but is not limited to - adding the above copyright notice to the beginning
 * of your source code files, and to any copyright notice that you may distribute
 * with programs based on this work.
 * 
 * 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 Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser 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.
 *
 */

/**
 * @file GenericFactory.hpp
 * @author Teng Lin
 * @date 10/24/2004
 * @version 1.0
 */
#ifndef UTIL_GENERICFACTORY_HPP
#define UTIL_GENERICFACTORY_HPP
#include <map>
#include <string>
#include <vector>

namespace oopse {

/**
 * @class GenericFactory GenericFactory.hpp "utils/GenericFactory.hpp"
 * @brief GenericFactory is a template based Object Factory 
 * Factory pattern is used to define an interface for creating an object.
 * 
 * @param Object the base class of the hierarchy for which you provide the object factory.
 * @param IdentType the object that identifies the type of the concrete object. Default type is string
 * @param Creator  the callable entity that creates objects. This type must support operator(),
 * taking no parameters and returning a pointer to Object. Default type is function pointer.
 *
 * @code
 * //Shape class
 * class Shape {
 * ...
 * };
 * 
 * //instantiating a new object factory
 * typedef GenericFactory<Shape> ShapeFactory;
 *
 * //Line class
 * class Line : public Shape{
 * ...
 * };
 *
 * //declare function to create Line
 * Shape* createLine() {
 *   return new Line;
 * }
 *
 * //register createLine
 * ShapeFactory::getInstance()->registerCreator("Line", createLine);
 *
 * //Circle class
 * class Circle : public Shape{
 * ...
 * };
 *
 * //declare function to create Circle
 * Shape* createCircle() { 
 *   return new Circle;
 * }
 *
 * //register createCircle
 * ShapeFactory::getInstance()->registerCreator("Circle", createCircle); 
 *
 * //create object by ident
 * Line* line = ShapeFactory::getInstance()->createObject("Line");
 * Circle* circle = ShapeFactory::getInstance()->createObject("Circle"); 
 * @endcode
 */
template<class Object, typename IdentType = std::string, typename Creator = Object* (*)()>
class GenericFactory {
    public:
        typedef GenericFactory<Object, IdentType, Creator> FactoryType;
        typedef std::map<IdentType, Creator> CreatorMapType;
        
        /**
         * Returns an instance of object factory
         * @return an instance of object factory
         */        
        static FactoryType* getInstance(){
            if (instance_ == NULL)
                instance_ = new FactoryType;
            return instance_;
        }

        /**
         * Registers a creator with a type identifier
         * @return true if registration is succeed, otherwise return false
         * @id the identification of the concrete object
         * @creator the object responsible to create the concrete object 
         */
        bool registerCreator(const IdentType& id, Creator creator) {
            return creatorMap_.insert(
                CreatorMapType::value_type(id, creator)).second;
        }

        /**
         * Unregisters the creator for the given type identifier. If the type identifier 
         * was previously registered, the function returns true.
         * @return truethe type identifier was previously registered and the creator is removed,
         * otherwise return false
         * @id the identification of the concrete object
         */
        bool unregisterCreator(const IdentType& id) {
            return creatorMap_.erase(id) == 1;
        }

        /**
         * Looks up the type identifier in the internal map. If it is found, it invokes the
         * corresponding creator for the type identifier and returns its result. 
         * @return a pointer of the concrete object, return NULL if no creator is registed for 
         * creating this concrete object
         * @id the identification of the concrete object
         */
        Object* createObject(const IdentType& id) {
            typename CreatorMapType::iterator i = creatorMap_.find(id);
            if (i != creatorMap_.end()) {
                return (i->second)();
            } else {
                return NULL;
            }
        }

        /** 
         *  Returns all of the registed  type identifiers
         * @return all of the registed  type identifiers
         */
        std::vector<IdentType> getIdents() {
            std::vector<IdentType> idents;
            typename CreatorMapType::iterator i;

            for (i = creatorMap_.begin(); i != creatorMap_.end(); ++i) {
                idents.push_back(i->first);
            }
            
            return idents;
        }

    public:
        static FactoryType* instance_;
        CreatorMapType creatorMap_;
};

/** write out all of the type identifier to a output stream */
template<typename O, typename I, typename C>
std::ostream& operator <<(std::ostream& o, GenericFactory<O, I, C>& factory) {
    std::vector<I> idents;
    std::vector<I>::iterator i;

    idents = factory.getIdents();

    o << "Avaliable type identifiers in this factory: " << std::endl;
    for (i = idents.begin(); i != idents.end(); ++i) {
        o << *i << std::endl;
    }

    return o;
}

//static template class member
template<class Object, typename IdentType,typename Creator>
GenericFactory<Object,IdentType,Creator>* GenericFactory<Object,IdentType,Creator>::instance_ ; 

#define DECLARE_CREATOR(abstractObject, concreteObject) \
    abstractObject* create##concreteObject(){\
        return new concreteObject;\
    }

}//namespace oopse
#endif //UTIL_GENERICFACTORY_HPP

Revision:	1641
Committed:	Sun Oct 24 07:55:48 2004 UTC (21 years ago) by tim
File size:	6411 byte(s)
Log Message:	GenericFactory pass unit test
#	User	Rev	Content
1	tim	1587	/*
2			* Copyright (C) 2000-2004 Object Oriented Parallel Simulation Engine (OOPSE) project
3			*
4			* Contact: oopse@oopse.org
5			*
6			* This program is free software; you can redistribute it and/or
7			* modify it under the terms of the GNU Lesser General Public License
8			* as published by the Free Software Foundation; either version 2.1
9			* of the License, or (at your option) any later version.
10			* All we ask is that proper credit is given for our work, which includes
11			* - but is not limited to - adding the above copyright notice to the beginning
12			* of your source code files, and to any copyright notice that you may distribute
13			* with programs based on this work.
14			*
15			* This program is distributed in the hope that it will be useful,
16			* but WITHOUT ANY WARRANTY; without even the implied warranty of
17			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18			* GNU Lesser General Public License for more details.
19			*
20			* You should have received a copy of the GNU Lesser General Public License
21			* along with this program; if not, write to the Free Software
22			* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23			*
24			*/
25
26			/**
27	tim	1641	* @file GenericFactory.hpp
28	tim	1587	* @author Teng Lin
29	tim	1641	* @date 10/24/2004
30	tim	1587	* @version 1.0
31			*/
32			#ifndef UTIL_GENERICFACTORY_HPP
33			#define UTIL_GENERICFACTORY_HPP
34			#include <map>
35			#include <string>
36	tim	1641	#include <vector>
37
38	tim	1592	namespace oopse {
39	tim	1641
40			/**
41			* @class GenericFactory GenericFactory.hpp "utils/GenericFactory.hpp"
42			* @brief GenericFactory is a template based Object Factory
43			* Factory pattern is used to define an interface for creating an object.
44			*
45			* @param Object the base class of the hierarchy for which you provide the object factory.
46			* @param IdentType the object that identifies the type of the concrete object. Default type is string
47			* @param Creator the callable entity that creates objects. This type must support operator(),
48			* taking no parameters and returning a pointer to Object. Default type is function pointer.
49			*
50			* @code
51			* //Shape class
52			* class Shape {
53			* ...
54			* };
55			*
56			* //instantiating a new object factory
57			* typedef GenericFactory<Shape> ShapeFactory;
58			*
59			* //Line class
60			* class Line : public Shape{
61			* ...
62			* };
63			*
64			* //declare function to create Line
65			* Shape* createLine() {
66			* return new Line;
67			* }
68			*
69			* //register createLine
70			* ShapeFactory::getInstance()->registerCreator("Line", createLine);
71			*
72			* //Circle class
73			* class Circle : public Shape{
74			* ...
75			* };
76			*
77			* //declare function to create Circle
78			* Shape* createCircle() {
79			* return new Circle;
80			* }
81			*
82			* //register createCircle
83			* ShapeFactory::getInstance()->registerCreator("Circle", createCircle);
84			*
85			* //create object by ident
86			* Line* line = ShapeFactory::getInstance()->createObject("Line");
87			* Circle* circle = ShapeFactory::getInstance()->createObject("Circle");
88			* @endcode
89			*/
90			template<class Object, typename IdentType = std::string, typename Creator = Object* (*)()>
91			class GenericFactory {
92	tim	1587	public:
93	tim	1641	typedef GenericFactory<Object, IdentType, Creator> FactoryType;
94			typedef std::map<IdentType, Creator> CreatorMapType;
95	tim	1587
96	tim	1641	/**
97			* Returns an instance of object factory
98			* @return an instance of object factory
99			*/
100			static FactoryType* getInstance(){
101			if (instance_ == NULL)
102			instance_ = new FactoryType;
103	tim	1592	return instance_;
104			}
105	tim	1587
106	tim	1641	/**
107			* Registers a creator with a type identifier
108			* @return true if registration is succeed, otherwise return false
109			* @id the identification of the concrete object
110			* @creator the object responsible to create the concrete object
111			*/
112			bool registerCreator(const IdentType& id, Creator creator) {
113			return creatorMap_.insert(
114			CreatorMapType::value_type(id, creator)).second;
115			}
116	tim	1587
117	tim	1641	/**
118			* Unregisters the creator for the given type identifier. If the type identifier
119			* was previously registered, the function returns true.
120			* @return truethe type identifier was previously registered and the creator is removed,
121			* otherwise return false
122			* @id the identification of the concrete object
123			*/
124			bool unregisterCreator(const IdentType& id) {
125			return creatorMap_.erase(id) == 1;
126	tim	1592	}
127	tim	1587
128	tim	1641	/**
129			* Looks up the type identifier in the internal map. If it is found, it invokes the
130			* corresponding creator for the type identifier and returns its result.
131			* @return a pointer of the concrete object, return NULL if no creator is registed for
132			* creating this concrete object
133			* @id the identification of the concrete object
134			*/
135			Object* createObject(const IdentType& id) {
136			typename CreatorMapType::iterator i = creatorMap_.find(id);
137	tim	1592	if (i != creatorMap_.end()) {
138	tim	1641	return (i->second)();
139	tim	1592	} else {
140	tim	1641	return NULL;
141	tim	1592	}
142			}
143
144	tim	1641	/**
145			* Returns all of the registed type identifiers
146			* @return all of the registed type identifiers
147			*/
148			std::vector<IdentType> getIdents() {
149			std::vector<IdentType> idents;
150			typename CreatorMapType::iterator i;
151	tim	1592
152	tim	1641	for (i = creatorMap_.begin(); i != creatorMap_.end(); ++i) {
153			idents.push_back(i->first);
154	tim	1592	}
155	tim	1641
156			return idents;
157	tim	1592	}
158	tim	1641
159			public:
160			static FactoryType* instance_;
161	tim	1592	CreatorMapType creatorMap_;
162	tim	1587	};
163
164	tim	1641	/** write out all of the type identifier to a output stream */
165			template<typename O, typename I, typename C>
166			std::ostream& operator <<(std::ostream& o, GenericFactory<O, I, C>& factory) {
167			std::vector<I> idents;
168			std::vector<I>::iterator i;
169	tim	1587
170	tim	1641	idents = factory.getIdents();
171
172			o << "Avaliable type identifiers in this factory: " << std::endl;
173			for (i = idents.begin(); i != idents.end(); ++i) {
174			o << *i << std::endl;
175	tim	1592	}
176
177	tim	1641	return o;
178			}
179
180			//static template class member
181			template<class Object, typename IdentType,typename Creator>
182			GenericFactory<Object,IdentType,Creator>* GenericFactory<Object,IdentType,Creator>::instance_ ;
183
184			#define DECLARE_CREATOR(abstractObject, concreteObject) \
185			abstractObject* create##concreteObject(){\
186			return new concreteObject;\
187			}
188
189	tim	1592	}//namespace oopse
190			#endif //UTIL_GENERICFACTORY_HPP
191