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 <cassert>
#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  std::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.
 *
 * Usage:
 * @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
 * //note: must put ShapeFactory::getInstance()->registerCreator("Line", createLine) on the right
 * //hand side, otherwise the compiler will consider it as a function declaration
 * const bool registeredLine = ShapeFactory::getInstance()->registerCreator("Line", createLine);
 *
 * //Circle class
 * class Circle : public Shape{
 * ...
 * };
 *
 * //declare function to create Circle
 * Shape* createCircle() { 
 *   return new Circle;
 * }
 *
 * //register createCircle
 * const bool registeredCircle = ShapeFactory::getInstance()->registerCreator("Circle", createCircle); 
 *
 * //create object by ident
 * Line* line = ShapeFactory::getInstance()->createObject("Line");
 * Circle* circle = ShapeFactory::getInstance()->createObject("Circle"); 
 * @endcode
 *
 * Or the user can use predefined macro DECLARE_CREATOR and REGISTER_CREATOR
 * @code
 * //Shape class
 * class Shape {
 * ...
 * };
 * 
 * //instantiating a new object factory
 * typedef GenericFactory<Shape> ShapeFactory;
 *
 * //Line class
 * class Line : public Shape{
 * ...
 * };
 *
 * //declare function using macro 
 * DECLARE_CREATOR(Shape, Line)
 * 
 * //register using macro
 * REGISTER_CREATOR(ShapeFactory, "Line", Line);
 
 * //Circle class
 * class Circle : public Shape{
 * ...
 * };
 *
 * //declare function using macro 
 * DECLARE_CREATOR(Shape, Circle)
 * 
 * //register using macro
 * REGISTER_CREATOR(ShapeFactory, "Circle", 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
         * @param id the identification of the concrete object
         */
        Object* createObject(const IdentType& id) {
            typename CreatorMapType::iterator i = creatorMap_.find(id);
            if (i != creatorMap_.end()) {
                //invoke functor to create object
                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 identifiers to an 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) \
    inline abstractObject* create##concreteObject(){\
        return new concreteObject;\
    }

#define REGISTER_CREATOR(factory, ident, concreteObject) \
        const bool registered##concreteObject = factory::getInstance()->registerCreator(ident, create##concreteObject); 


}//namespace oopse
#endif //UTIL_GENERICFACTORY_HPP

Revision:	1829
Committed:	Thu Dec 2 05:14:58 2004 UTC (19 years, 8 months ago) by tim
File size:	7601 byte(s)
Log Message:	minor fix
#	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	tim	1643	#include <cassert>
35	tim	1587	#include <map>
36			#include <string>
37	tim	1641	#include <vector>
38
39	tim	1592	namespace oopse {
40	tim	1641
41			/**
42			* @class GenericFactory GenericFactory.hpp "utils/GenericFactory.hpp"
43			* @brief GenericFactory is a template based Object Factory
44			* Factory pattern is used to define an interface for creating an object.
45			*
46			* @param Object the base class of the hierarchy for which you provide the object factory.
47	tim	1829	* @param IdentType the object that identifies the type of the concrete object. Default type is std::string * @param Creator the callable entity that creates objects. This type must support operator(),
48	tim	1641	* taking no parameters and returning a pointer to Object. Default type is function pointer.
49			*
50	tim	1643	* Usage:
51	tim	1641	* @code
52			* //Shape class
53			* class Shape {
54			* ...
55			* };
56			*
57			* //instantiating a new object factory
58			* typedef GenericFactory<Shape> ShapeFactory;
59			*
60			* //Line class
61			* class Line : public Shape{
62			* ...
63			* };
64			*
65			* //declare function to create Line
66			* Shape* createLine() {
67			* return new Line;
68			* }
69			*
70			* //register createLine
71	tim	1643	* //note: must put ShapeFactory::getInstance()->registerCreator("Line", createLine) on the right
72			* //hand side, otherwise the compiler will consider it as a function declaration
73			* const bool registeredLine = ShapeFactory::getInstance()->registerCreator("Line", createLine);
74	tim	1641	*
75			* //Circle class
76			* class Circle : public Shape{
77			* ...
78			* };
79			*
80			* //declare function to create Circle
81			* Shape* createCircle() {
82			* return new Circle;
83			* }
84			*
85			* //register createCircle
86	tim	1643	* const bool registeredCircle = ShapeFactory::getInstance()->registerCreator("Circle", createCircle);
87	tim	1641	*
88			* //create object by ident
89			* Line* line = ShapeFactory::getInstance()->createObject("Line");
90			* Circle* circle = ShapeFactory::getInstance()->createObject("Circle");
91			* @endcode
92	tim	1643	*
93			* Or the user can use predefined macro DECLARE_CREATOR and REGISTER_CREATOR
94			* @code
95			* //Shape class
96			* class Shape {
97			* ...
98			* };
99			*
100			* //instantiating a new object factory
101			* typedef GenericFactory<Shape> ShapeFactory;
102			*
103			* //Line class
104			* class Line : public Shape{
105			* ...
106			* };
107			*
108			* //declare function using macro
109			* DECLARE_CREATOR(Shape, Line)
110			*
111			* //register using macro
112			* REGISTER_CREATOR(ShapeFactory, "Line", Line);
113
114			* //Circle class
115			* class Circle : public Shape{
116			* ...
117			* };
118			*
119			* //declare function using macro
120			* DECLARE_CREATOR(Shape, Circle)
121			*
122			* //register using macro
123			* REGISTER_CREATOR(ShapeFactory, "Circle", Circle);
124			* @endcode
125	tim	1641	*/
126			template<class Object, typename IdentType = std::string, typename Creator = Object* (*)()>
127			class GenericFactory {
128	tim	1587	public:
129	tim	1641	typedef GenericFactory<Object, IdentType, Creator> FactoryType;
130			typedef std::map<IdentType, Creator> CreatorMapType;
131	tim	1587
132	tim	1641	/**
133			* Returns an instance of object factory
134			* @return an instance of object factory
135			*/
136			static FactoryType* getInstance(){
137			if (instance_ == NULL)
138			instance_ = new FactoryType;
139	tim	1592	return instance_;
140			}
141	tim	1587
142	tim	1641	/**
143			* Registers a creator with a type identifier
144			* @return true if registration is succeed, otherwise return false
145			* @id the identification of the concrete object
146			* @creator the object responsible to create the concrete object
147			*/
148			bool registerCreator(const IdentType& id, Creator creator) {
149			return creatorMap_.insert(
150			CreatorMapType::value_type(id, creator)).second;
151			}
152	tim	1587
153	tim	1641	/**
154			* Unregisters the creator for the given type identifier. If the type identifier
155			* was previously registered, the function returns true.
156			* @return truethe type identifier was previously registered and the creator is removed,
157			* otherwise return false
158			* @id the identification of the concrete object
159			*/
160			bool unregisterCreator(const IdentType& id) {
161			return creatorMap_.erase(id) == 1;
162	tim	1592	}
163	tim	1587
164	tim	1641	/**
165			* Looks up the type identifier in the internal map. If it is found, it invokes the
166			* corresponding creator for the type identifier and returns its result.
167			* @return a pointer of the concrete object, return NULL if no creator is registed for
168			* creating this concrete object
169	tim	1642	* @param id the identification of the concrete object
170	tim	1641	*/
171			Object* createObject(const IdentType& id) {
172			typename CreatorMapType::iterator i = creatorMap_.find(id);
173	tim	1592	if (i != creatorMap_.end()) {
174	tim	1643	//invoke functor to create object
175	tim	1641	return (i->second)();
176	tim	1592	} else {
177	tim	1641	return NULL;
178	tim	1592	}
179			}
180
181	tim	1641	/**
182			* Returns all of the registed type identifiers
183			* @return all of the registed type identifiers
184			*/
185			std::vector<IdentType> getIdents() {
186			std::vector<IdentType> idents;
187			typename CreatorMapType::iterator i;
188	tim	1592
189	tim	1641	for (i = creatorMap_.begin(); i != creatorMap_.end(); ++i) {
190			idents.push_back(i->first);
191	tim	1592	}
192	tim	1641
193			return idents;
194	tim	1592	}
195	tim	1641
196			public:
197			static FactoryType* instance_;
198	tim	1592	CreatorMapType creatorMap_;
199	tim	1587	};
200
201	tim	1681	/** write out all of the type identifiers to an output stream */
202	tim	1641	template<typename O, typename I, typename C>
203			std::ostream& operator <<(std::ostream& o, GenericFactory<O, I, C>& factory) {
204			std::vector<I> idents;
205			std::vector<I>::iterator i;
206	tim	1587
207	tim	1641	idents = factory.getIdents();
208
209			o << "Avaliable type identifiers in this factory: " << std::endl;
210			for (i = idents.begin(); i != idents.end(); ++i) {
211			o << *i << std::endl;
212	tim	1592	}
213
214	tim	1641	return o;
215			}
216
217			//static template class member
218			template<class Object, typename IdentType,typename Creator>
219			GenericFactory<Object,IdentType,Creator>* GenericFactory<Object,IdentType,Creator>::instance_ ;
220
221	tim	1643
222	tim	1641	#define DECLARE_CREATOR(abstractObject, concreteObject) \
223	tim	1643	inline abstractObject* create##concreteObject(){\
224	tim	1641	return new concreteObject;\
225			}
226
227	tim	1643	#define REGISTER_CREATOR(factory, ident, concreteObject) \
228			const bool registered##concreteObject = factory::getInstance()->registerCreator(ident, create##concreteObject);
229
230
231	tim	1592	}//namespace oopse
232			#endif //UTIL_GENERICFACTORY_HPP
233