34 lines
902 B
Markdown
34 lines
902 B
Markdown
---
|
|
layout: pattern
|
|
title: Memento
|
|
folder: memento
|
|
permalink: /patterns/memento/
|
|
categories: Behavioral
|
|
tags:
|
|
- Gang of Four
|
|
---
|
|
|
|
## Also known as
|
|
Token
|
|
|
|
## Intent
|
|
Without violating encapsulation, capture and externalize an
|
|
object's internal state so that the object can be restored to this state later.
|
|
|
|
## Class diagram
|
|
|
|
|
|
## Applicability
|
|
Use the Memento pattern when
|
|
|
|
* a snapshot of an object's state must be saved so that it can be restored to that state later, and
|
|
* a direct interface to obtaining the state would expose implementation details and break the object's encapsulation
|
|
|
|
## Real world examples
|
|
|
|
* [java.util.Date](http://docs.oracle.com/javase/8/docs/api/java/util/Date.html)
|
|
|
|
## Credits
|
|
|
|
* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
|