设计模式 备忘录模式

public class Memento {

private String state;

public Memento (String state)
{
this.state=state;
}

public String getState() {
return state;
}
}

public class Originator {

private String state;

public Memento CreateMemento()
{
return new Memento(state);
}

public void SetMemento(Memento memento)
{
state = memento.getState();
}

public void Show()
{
System.out.println("State="+state);
}

public String getState() {
return state;
}

public void setState(String state) {
this.state = state;
}

}

public class Caretaker {

private Memento memento;

public Memento getMemento() {
return memento;
}

public void setMemento(Memento memento) {
this.memento = memento;
}

}

public class Program {

public static void main(String[] args) {
// TODO Auto-generated method stub

Originator originator = new Originator();
originator.setState("On");
originator.Show();

Caretaker caretaker = new Caretaker();
caretaker.setMemento(originator.CreateMemento());

originator.setState("off");
originator.Show();

originator.SetMemento(caretaker.getMemento());
originator.Show();

}

}