Mememto 備忘錄模式

package com.lonton.designpatterns;

import java.util.List;
import java.util.ArrayList;

class Life
{
	private String time;
	private List<Mememto> mememtos = new ArrayList<Mememto>();

	public void setTime(String time)
	{
		System.out.println("Setting time to " + time);
		this.time = time;
	}
	
	public void saveToMememto()
	{
		System.out.println("Saving time: " + time +  " to Memento");
		mememtos.add(new Mememto(time));
	}
	
	public void restoreFromMememto(int index)
	{
		time = mememtos.get(index).getSavedTime();
		System.out.println("Time restored from Memento: " + time);
	}
	
    class Mememto
	{
		private final String time;
		
		public Mememto(String time)
		{
			this.time = time;
		}
		
		public String getSavedTime()
		{
			return time;
		}
	}
}

public class MememtoTest
{
	public static void main(String[] args)
	{
		Life life = new Life();
		
		life.setTime("2000 B.C");;
		life.saveToMememto();
		
		life.setTime("1000 B.C");;
		life.saveToMememto();
		
		life.setTime("2000 A.D");;
		life.saveToMememto();
		
		life.setTime("2008 A.D");;
		life.saveToMememto();
		
		life.restoreFromMememto(2);
	}	
}