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 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 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) \
    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:	150
Committed:	Mon Oct 25 17:03:56 2004 UTC (21 years ago) by tim
File size:	7594 byte(s)
Log Message:	adding GenericFactory Test Case. GenericFactory now can bed used to creat ForcefieldFactory and IntegratorFactory etc.
#	Content
1	/*
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	* @file GenericFactory.hpp
28	* @author Teng Lin
29	* @date 10/24/2004
30	* @version 1.0
31	*/
32	#ifndef UTIL_GENERICFACTORY_HPP
33	#define UTIL_GENERICFACTORY_HPP
34	#include <cassert>
35	#include <map>
36	#include <string>
37	#include <vector>
38
39	namespace oopse {
40
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	* @param IdentType the object that identifies the type of the concrete object. Default type is string
48	* @param Creator the callable entity that creates objects. This type must support operator(),
49	* taking no parameters and returning a pointer to Object. Default type is function pointer.
50	*
51	* Usage:
52	* @code
53	* //Shape class
54	* class Shape {
55	* ...
56	* };
57	*
58	* //instantiating a new object factory
59	* typedef GenericFactory<Shape> ShapeFactory;
60	*
61	* //Line class
62	* class Line : public Shape{
63	* ...
64	* };
65	*
66	* //declare function to create Line
67	* Shape* createLine() {
68	* return new Line;
69	* }
70	*
71	* //register createLine
72	* //note: must put ShapeFactory::getInstance()->registerCreator("Line", createLine) on the right
73	* //hand side, otherwise the compiler will consider it as a function declaration
74	* const bool registeredLine = ShapeFactory::getInstance()->registerCreator("Line", createLine);
75	*
76	* //Circle class
77	* class Circle : public Shape{
78	* ...
79	* };
80	*
81	* //declare function to create Circle
82	* Shape* createCircle() {
83	* return new Circle;
84	* }
85	*
86	* //register createCircle
87	* const bool registeredCircle = ShapeFactory::getInstance()->registerCreator("Circle", createCircle);
88	*
89	* //create object by ident
90	* Line* line = ShapeFactory::getInstance()->createObject("Line");
91	* Circle* circle = ShapeFactory::getInstance()->createObject("Circle");
92	* @endcode
93	*
94	* Or the user can use predefined macro DECLARE_CREATOR and REGISTER_CREATOR
95	* @code
96	* //Shape class
97	* class Shape {
98	* ...
99	* };
100	*
101	* //instantiating a new object factory
102	* typedef GenericFactory<Shape> ShapeFactory;
103	*
104	* //Line class
105	* class Line : public Shape{
106	* ...
107	* };
108	*
109	* //declare function using macro
110	* DECLARE_CREATOR(Shape, Line)
111	*
112	* //register using macro
113	* REGISTER_CREATOR(ShapeFactory, "Line", Line);
114
115	* //Circle class
116	* class Circle : public Shape{
117	* ...
118	* };
119	*
120	* //declare function using macro
121	* DECLARE_CREATOR(Shape, Circle)
122	*
123	* //register using macro
124	* REGISTER_CREATOR(ShapeFactory, "Circle", Circle);
125	* @endcode
126	*/
127	template<class Object, typename IdentType = std::string, typename Creator = Object* (*)()>
128	class GenericFactory {
129	public:
130	typedef GenericFactory<Object, IdentType, Creator> FactoryType;
131	typedef std::map<IdentType, Creator> CreatorMapType;
132
133	/**
134	* Returns an instance of object factory
135	* @return an instance of object factory
136	*/
137	static FactoryType* getInstance(){
138	if (instance_ == NULL)
139	instance_ = new FactoryType;
140	return instance_;
141	}
142
143	/**
144	* Registers a creator with a type identifier
145	* @return true if registration is succeed, otherwise return false
146	* @id the identification of the concrete object
147	* @creator the object responsible to create the concrete object
148	*/
149	bool registerCreator(const IdentType& id, Creator creator) {
150	return creatorMap_.insert(
151	CreatorMapType::value_type(id, creator)).second;
152	}
153
154	/**
155	* Unregisters the creator for the given type identifier. If the type identifier
156	* was previously registered, the function returns true.
157	* @return truethe type identifier was previously registered and the creator is removed,
158	* otherwise return false
159	* @id the identification of the concrete object
160	*/
161	bool unregisterCreator(const IdentType& id) {
162	return creatorMap_.erase(id) == 1;
163	}
164
165	/**
166	* Looks up the type identifier in the internal map. If it is found, it invokes the
167	* corresponding creator for the type identifier and returns its result.
168	* @return a pointer of the concrete object, return NULL if no creator is registed for
169	* creating this concrete object
170	* @param id the identification of the concrete object
171	*/
172	Object* createObject(const IdentType& id) {
173	typename CreatorMapType::iterator i = creatorMap_.find(id);
174	if (i != creatorMap_.end()) {
175	//invoke functor to create object
176	return (i->second)();
177	} else {
178	return NULL;
179	}
180	}
181
182	/**
183	* Returns all of the registed type identifiers
184	* @return all of the registed type identifiers
185	*/
186	std::vector<IdentType> getIdents() {
187	std::vector<IdentType> idents;
188	typename CreatorMapType::iterator i;
189
190	for (i = creatorMap_.begin(); i != creatorMap_.end(); ++i) {
191	idents.push_back(i->first);
192	}
193
194	return idents;
195	}
196
197	public:
198	static FactoryType* instance_;
199	CreatorMapType creatorMap_;
200	};
201
202	/** write out all of the type identifier to a output stream */
203	template<typename O, typename I, typename C>
204	std::ostream& operator <<(std::ostream& o, GenericFactory<O, I, C>& factory) {
205	std::vector<I> idents;
206	std::vector<I>::iterator i;
207
208	idents = factory.getIdents();
209
210	o << "Avaliable type identifiers in this factory: " << std::endl;
211	for (i = idents.begin(); i != idents.end(); ++i) {
212	o << *i << std::endl;
213	}
214
215	return o;
216	}
217
218	//static template class member
219	template<class Object, typename IdentType,typename Creator>
220	GenericFactory<Object,IdentType,Creator>* GenericFactory<Object,IdentType,Creator>::instance_ ;
221
222
223	#define DECLARE_CREATOR(abstractObject, concreteObject) \
224	inline abstractObject* create##concreteObject(){\
225	return new concreteObject;\
226	}
227
228	#define REGISTER_CREATOR(factory, ident, concreteObject) \
229	const bool registered##concreteObject = factory::getInstance()->registerCreator(ident, create##concreteObject);
230
231
232	}//namespace oopse
233	#endif //UTIL_GENERICFACTORY_HPP
234