////////////////////////////////////////////////////////////////////////////////
// class template Factory
// Implements a generic object factory
////////////////////////////////////////////////////////////////////////////////
template
<
class AbstractProduct,
typename IdentifierType,
typename ProductCreator = AbstractProduct* (*)(),
template<typename, class>
class FactoryErrorPolicy = DefaultFactoryError
>
class Factory
: public FactoryErrorPolicy<IdentifierType, AbstractProduct>
{
public:
bool Register(const IdentifierType& id, ProductCreator creator)
{
return associations_.insert(
IdToProductMap::value_type(id, creator)).second;
}
bool Unregister(const IdentifierType& id)
{
return associations_.erase(id) == 1;
}
AbstractProduct* CreateObject(const IdentifierType& id)
{
typename IdToProductMap::iterator i = associations_.find(id);
if (i != associations_.end())
{
return (i->second)();
}
return OnUnknownType(id);
}
private:
typedef AssocVector<IdentifierType, ProductCreator> IdToProductMap;
IdToProductMap associations_;
};