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memento/README.md

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+---
+layout: pattern
+title: Memento
+folder: memento
+permalink: /patterns/memento/
+categories: Behavioral
+tags:
+ - Java
+ - Gang Of Four
+ - Difficulty-Intermediate
+---
+
+## 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.
+
+![alt text](./etc/memento.png "Memento")
+
+## 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)