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The memento pattern is a software design pattern that provides the ability to restore an object to its previous state (undo via rollback).
The memento pattern is used by two objects: the originator and a caretaker. The originator is some object that has an internal state. The caretaker is going to do something to the originator, but wants to be able to undo the change. The caretaker first asks the originator for a memento object. Then it does whatever operation (or sequence of operations) it was going to do. To roll back to the state before the operations, it returns the memento object to the originator. The memento object itself is an opaque object (one which the caretaker can not, or should not, change). When using this pattern, care should be taken if the originator may change other objects or resources - the memento pattern operates on a single object.
created by syam1224 on 2008-05-07 20:42:39
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Memento Design Pattern from Sourcemaking
* Without violating encapsulation, capture and externalize an object's internal state so that the object can be returned to this state later.
* A magic cookie that encapsulates a "check point" capability.
* Promote undo or rollback to full object status.
http://sourcemaking.com/design_patterns/memento
created by syam1224 on 2008-05-07 20:49:15
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Memento from vincehuston.org
Intent
* Without violating encapsulation, capture and externalize an object's internal state so that the object can be returned to this state later. [GoF, p283]
* A magic cookie that encapsulates a "check point" capability.
* Promote undo or rollback to full object status.
http://www.vincehuston.org/dp/memento.html
created by syam1224 on 2008-05-07 20:51:00
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Memento D
Without violating encapsulation, capture and externalize an object's internal state so that the object can be restored to this state later.
http://www.dofactory.com/Patterns/PatternMemento.a
created by syam1224 on 2008-05-07 20:52:33
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Memento Design Pattern from Wikipedia
Classic examples of the memento pattern include the seed of a pseudorandom number generator and the state in a finite state machine.
http://en.wikipedia.org/wiki/Memento_pattern
created by syam1224 on 2008-05-07 20:51:53
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