libcore/include/sirikata/core/util/Factory.hpp

Go to the documentation of this file.

/*  Sirikata Utilities -- Sirikata Utilities
 *  Factory.hpp
 *
 *  Copyright (c) 2009, Daniel Reiter Horn
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are
 *  met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  * Neither the name of Sirikata nor the names of its contributors may
 *    be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _SIRIKATA_FACTORY_HPP_
#define _SIRIKATA_FACTORY_HPP_

namespace Sirikata {

class FactoryMissingConstructorException : public std::exception {
public:
    FactoryMissingConstructorException(const String& _name)
     : name(_name),
       what_msg(new String())
    {}
    FactoryMissingConstructorException(const FactoryMissingConstructorException& rhs)
     : name(rhs.name),
       what_msg(new String(*(rhs.what_msg)))
    {}
    virtual ~FactoryMissingConstructorException() throw() {
        delete what_msg;
    }

    char const* what() const throw() {
        if (what_msg->empty())
            (*what_msg) = "Factory missing constructor: " + name + " not registered in the factory.";
        return what_msg->c_str();
    }
private:
    const String name;
    String* what_msg;
};

template<class T, class Ftype>
class FactoryImpl {

    typedef std::tr1::unordered_map<String,Ftype> ConstructorMap;
    ConstructorMap mConstructors;
    template <class U> static U* noop(U*) {
        return NULL;
    }
    template <class U> static U noop(const U&) {
        return U();
    }
    static T staticNoop() {
        T temp=T();
        return noop(temp);
    }
    Ftype mNoop;
    String mDefault;
public:
    FactoryImpl():mNoop(std::tr1::bind(&FactoryImpl<T,Ftype>::staticNoop)){}
    bool unregisterConstructor(const String& name) {

        typename ConstructorMap::iterator where=mConstructors.find(name);
        if (where==mConstructors.end())
            return false;
        mConstructors.erase(where);
        if (mDefault==name) {
            mDefault=String();
        }
        return true;
    }
    bool registerConstructor(const String& name,
                             const Ftype &constructor,
                             bool isDefault=false) {
        if (mConstructors.find(name)!=mConstructors.end())
            return false;
        mConstructors[name]=constructor;
        if (isDefault) {
            mDefault=name;
        }
        return true;
    }
    const String& getDefault() const {
        return mDefault;
    }
    bool hasConstructor(const String&name)const {
        return mConstructors.find(name) != mConstructors.end();
    }
    typedef std::list<String> ConstructorNameList;
    ConstructorNameList getNames() const {
        ConstructorNameList result;
        for(typename ConstructorMap::const_iterator it = mConstructors.begin(); it != mConstructors.end(); it++)
            result.push_back(it->first);
        return result;
    }

    const Ftype &getConstructorOrDefault(const String&name)const{
        typename ConstructorMap::const_iterator where=mConstructors.find(name);
        if (where==mConstructors.end()) {
            if (name.length()==0&&mDefault.length()) {
                return getConstructor(mDefault);
            }
            return mNoop;
        }
        return where->second;
    }

    // Gets a specific constructor and throws a
    // FactoryMissingConstructorException if it can't be found
    const Ftype& getConstructor(const String&name) const {
        if (!hasConstructor(name))
            throw FactoryMissingConstructorException(name);
        return getConstructorOrDefault(name);
    }

    const Ftype& getDefaultConstructor()const{
        return getConstructor(mDefault);
    }
};

template <class T>class Factory:public FactoryImpl<T,std::tr1::function<T()> >{};

template <class T, typename A>class Factory1:public FactoryImpl<T,std::tr1::function<T(A)> >{};

template <class T, typename A, typename B>class Factory2:public FactoryImpl<T,std::tr1::function<T(A,B)> >{};

template <class T, typename A, typename B, typename C>class Factory3:public FactoryImpl<T,std::tr1::function<T(A,B,C)> >{};

template <class T, typename A, typename B, typename C, typename D>class Factory4:public FactoryImpl<T,std::tr1::function<T(A,B,C,D)> >{};

template <class T, typename A, typename B, typename C, typename D, typename E>class Factory5:public FactoryImpl<T,std::tr1::function<T(A,B,C,D,E)> >{};

template <class T, typename A, typename B, typename C, typename D, typename E, typename F>class Factory6:public FactoryImpl<T,std::tr1::function<T(A,B,C,D,E,F)> >{};

}
#endif