[设计模式]之十四:备忘录模式

public class Originator {
	private String state; // 需要保存的属性
	
	public String getState() {
		return state;
	}

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

	public Memento createMemento() { //创建备忘录，把自己的状态保存进去
		return new Memento(state);
	}
	
	public void setMemento(Memento memento) { //根据备忘录恢复数据
		state = memento.getState();
	}
	
	public void show() {
		System.out.println("State is " + state);
	}
}
//备忘录
public class Memento {
	private String state;
	
	public String getState() {
		return state;
	}

	public Memento(String state) {
		this.state = state;
	}
	
}
//管理者
public class Caretaker {
	private Memento memento;

	public Memento getMemento() {
		return memento;
	}

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

// 客户代码
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();
}
//输出
State is On
State is Off
State is On