Structural example
#include <iostream>
#include <string>
using namespace std;
class Memento {
private:
string _state;
protected:
friend class Originator;
Memento(const string &state) {
_state = state;
}
// Gets or sets state
string getState() {
return _state;
}
};
class Originator {
private:
string _state;
public:
// Property
string getState() {
return _state;
}
void setState(const string &value) {
_state = value;
cout << "State = " << _state << endl;
}
// Creates memento
Memento* CreateMemento() {
return new Memento(_state);
}
// Restores original state
void SetMemento(Memento *memento) {
cout << "Restoring state..." << endl;
setState(memento->getState());
}
};
class Caretaker {
private:
Memento *_memento;
public:
Caretaker() {
_memento = NULL;
}
~Caretaker() {
if (_memento != NULL) {
delete _memento;
}
}
void setMemento(Memento *memento) {
_memento = memento;
}
Memento* getMemento() {
return _memento;
}
};
////////
int main() {
Originator *o = new Originator;
o->setState("ON");
// Store internal state
Caretaker *c = new Caretaker;
c->setMemento(o->CreateMemento());
// Continue changing originator
o->setState("OFF");
// Restore saved state
o->SetMemento(c->getMemento());
delete c;
delete o;
return 0;
}
Real World example
#include <iostream>
#include <string>
using namespace std;
// The 'Memento' class
class Memento {
private:
string _name;
string _phone;
double _budget;
public:
friend class SalesProspect;
// Constructor
Memento(const string &name, const string &phone, double budget) {
_name = name;
_phone = phone;
_budget = budget;
}
// Gets or sets name
string getName() {
return _name;
}
void setName(const string &name) {
_name = name;
}
// Gets or sets phone
string getPhone() {
return _phone;
}
void setPhone(const string &phone) {
_phone = phone;
}
// Gets or sets budget
double getBudget() {
return _budget;
}
void setBudget(double budget) {
_budget = budget;
}
};
// The 'Originator' class
class SalesProspect {
private:
string _name;
string _phone;
double _budget;
public:
// Gets or sets name
string getName() {
return _name;
}
void setName(const string &name) {
_name = name;
cout << "Name: " << _name << endl;
}
// Gets or sets phone
string getPhone() {
return _phone;
}
void setPhone(const string &phone) {
_phone = phone;
cout << "Phone: " << _phone << endl;
}
// Gets or sets budget
double getBudget() {
return _budget;
}
void setBudget(double budget) {
_budget = budget;
cout << "Budget: " << _budget << endl;
}
// Stores memento
Memento *SaveMemento() {
cout << endl;
cout << "Saving state --" << endl;
return new Memento(_name, _phone, _budget);
}
// Restores memento
void RestoreMemento(Memento *memento) {
cout << endl;
cout << "Restoreing state --" << endl;
setName(memento->getName());
setPhone(memento->getPhone());
setBudget(memento->getBudget());
}
};
// The 'Caretaker' class
class ProspectMemory {
private:
Memento *_memento;
public:
ProspectMemory() {
_memento = NULL;
}
~ProspectMemory() {
if (_memento) {
delete _memento;
}
}
// Property
Memento* getMemento() {
return _memento;
}
void setMemento(Memento *memento) {
_memento = memento;
}
};
// Entry point into console application.
int main() {
SalesProspect *s = new SalesProspect; // prospect: 見込み
s->setName("Noel van Halen");
s->setPhone("(412) 256-0990");
s->setBudget(25000.0); // budget: 予算
// Store internal state
ProspectMemory *m = new ProspectMemory;
m->setMemento(s->SaveMemento());
// Continue changing originator
s->setName("Leo Welch");
s->setPhone("(310) 209-7111");
s->setBudget(1000000.0);
// Restore saved state
s->RestoreMemento(m->getMemento());
delete s;
delete m;
// Wait for user
return 0;
}
参考サイト
最終更新：2011年12月14日 01:16
