Полиморфизм и шаблонные методы класса

template <class Ch> class EventIO // interface for derived classes
    {
    public:
        typedef std::basic_string<Ch> string_type;
 
        template <class Value>
virtual bool write_value(const string_type& name_value, const Value& value) = 0;
        template <class Value> 
virtual Value read_value(const string_type& name_value) = 0; // throw
    };

template <class Ch> class EventIO // interface for derived classes
    {
    public:
        typedef std::basic_string<Ch> string_type;
 
        template <class Value> virtual bool write_value(const string_type& name_value, const Value& value) = 0;
        template <class Value> virtual Value read_value(const string_type& name_value) = 0; // throw
    };

template <class Ch> class XML_IOEvent : public EventIO<Ch>
    {
    public:
        XML_IOEvent(const string_type& filename) : _filename(filename), pt() {}
        // write 1 value to the file
        template <class Value> virtual bool write_value(const string_type& name_value, const Value& value);
        // extract 1 value from the file
        template <class Value> virtual Value read_value(const string_type& name_value); // throw
    private:
        string_type _filename;
        boost::property_tree::ptree pt;
    };

template <typename T>
class A
{};
 
template <typename T>
class B : public A<T>
{};

template <typename T>
class A
{
public:
    virtual void foo() = 0;
};
 
template <typename T, typename U>
class B : public A<T>
{
public:
    // works with type U
    void foo() { std::cout << "Done"; }
};

template<class Ch> class IOSystem
{
public:
    typedef std::basic_string<Ch> string_type;
 
    virtual bool write(const string_type& _filename, const string_type& _address) = 0;
    virtual string_type read(const string_type& _filename, const string_type& _address) = 0; // throw
 
    virtual ~IO_System() {}
};
template<class T, class U>
class D: public IOSystem<U>
{
public:
 virtual bool write(const string_type& _filename, const string_type& _address)
{
T val;}
    virtual string_type read(const string_type& _filename, const string_type& _address)
{
T val;}
}

struct my_class
{
    template<typename T>inline void some_method();
    virtual void some_method_int(){}//заглушка
    virtual void some_method_bool(){}//заглушка
};
template<>inline void my_class::some_method<int>(){some_method_int();}
template<>inline void my_class::some_method<bool>(){some_method_bool();}