mirror of
https://github.com/DesignPatternsPHP/DesignPatternsPHP.git
synced 2025-08-15 11:24:01 +02:00
Change index.rst to README.rst
remove all pattern's README.md
This commit is contained in:
@@ -1,22 +0,0 @@
|
||||
# Memento
|
||||
|
||||
## Purpose
|
||||
|
||||
Provide the ability to restore an object to its previous state (undo via rollback).
|
||||
|
||||
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.
|
||||
|
||||
## Examples
|
||||
|
||||
* The seed of a pseudorandom number generator
|
||||
* The state in a finite state machine
|
||||
|
||||
## UML Diagram
|
||||
|
||||

|
Reference in New Issue
Block a user