template<class BaseType>
class BaseFactory
{
	public:
		virtual BaseType* create() = 0;
};

template<class BaseType, class T>
class DerivedFactory : public BaseFactory<BaseType>
{
	public:
		virtual BaseType* create()
		{
			return new T();
		}
};


template<typename KeyType, class BaseType>
class ChildFactoryMap
{
	private:
		typedef std::map<KeyType, BaseFactory<BaseType>*> MapType;
		MapType derivedFactories;
	public:
		~ChildFactoryMap()
		{
			for(typename MapType::iterator i = derivedFactories.begin();
				i != derivedFactories.end(); ++i)
			{
				delete i->second;
			}
		}

		template<typename T>
		void addType(const KeyType& key)
		{
			derivedFactories.insert(typename MapType::value_type(key, new DerivedFactory<BaseType, T>);
		}

		BaseType* create(const KeyType& key)
		{
			return derivedFactories.get(key)->create();
		}
};