Реализации на С++

Memento

Общая реализация на языке С++

includes

# include <iostream>
# include <memory>
# include <list>

using namespace std;

Caretaker

class Memento;

class Caretaker
{
public:
    unique_ptr<Memento> getMemento();
    void setMemento(unique_ptr<Memento> memento);
private:
    list<unique_ptr<Memento>> mementos;
};

Originator

class Originator
{
public:
    Originator(int s) : state(s) {}
    const int getState() const 
    { 
        return state; 
    }
    void setState(int s) 
    { 
        state = s; 
    }
    std::unique_ptr<Memento> createMemento() 
    { 
        return make_unique<Memento>(*this); 
    }
    void restoreMemento(std::unique_ptr<Memento> memento);
private:
    int state;
};

Memento

class Memento
{
    friend class Originator;
public:
    Memento(Originator o) : originator(o) {}
private:
    void setOriginator(Originator o) 
    { 
        originator = o; 
    }
    Originator getOriginator() 
    { 
        return originator; 
    }
private:
    Originator originator;
};

Methods Caretaker

# pragma region Methods Caretaker
void Caretaker::setMemento(unique_ptr<Memento> memento)
{
    mementos.push_back(move(memento));
}
unique_ptr<Memento> Caretaker::getMemento() 
{
    unique_ptr<Memento> last = move(mementos.back());
    mementos.pop_back();
    return last;
}
# pragma endregion

Method Originator

# pragma region Method Originator
void Originator::restoreMemento(std::unique_ptr<Memento> memento)
{
    *this = memento->getOriginator();
}
# pragma endregion

int main()
{
    auto originator = make_unique<Originator>(1);
    auto caretaker = make_unique<Caretaker>();

    cout << "State = " << originator->getState() << endl;
    caretaker->setMemento(originator->createMemento());

    originator->setState(2);
    cout << "State = " << originator->getState() << endl;
    caretaker->setMemento(originator->createMemento());
    originator->setState(3);
    cout << "State = " << originator->getState() << endl;
    caretaker->setMemento(originator->createMemento());

    originator->restoreMemento(caretaker->getMemento());
    cout << "State = " << originator->getState() << endl;
    originator->restoreMemento(caretaker->getMemento());
    cout << "State = " << originator->getState() << std::endl;
    originator->restoreMemento(caretaker->getMemento());
    cout << "State = " << originator->getState() << std::endl;
}