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Improve Memento Javadoc

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Ilkka Seppala 2015-10-03 23:38:37 +03:00
parent fc66ae8084
commit ca6bb7a3a8
1 changed files with 14 additions and 1 deletions
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memento/src/main/java/com/iluwatar/memento/App.java
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@ -4,7 +4,20 @@ import java.util.Stack;
/** /**
* *
* Memento pattern is for storing and restoring object state. The object ({@link Star}) * The Memento pattern is a software design pattern that provides the ability to restore
* an object to its previous state (undo via rollback).
* <p>
* The Memento pattern is implemented with three objects: the originator, a caretaker and
* a memento. 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 cannot, 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.
* <p>
* In this example the object ({@link Star})
* gives out a "memento" ({@link StarMemento}) that contains the state of the object. * gives out a "memento" ({@link StarMemento}) that contains the state of the object.
* Later on the memento can be set back to the object restoring the state. * Later on the memento can be set back to the object restoring the state.
* *