Python design mode 22nd Day "Memo mode"

1. Application Scenarios

(1) Can save the state of the object, and can revert to the previous state

2. Code implementation

#!/usr/bin/env python#! _*_ coding:utf-8 _*_classoriginator (object):" "This is the basic class" "    def __init__(self, State): Self.state= StatedefCreatememento (self):" "Create a Memo" "        returnMemento (self.state)defSetmemento (Self, memento):" "Recover from Memo" "self.state=memento.stateclassMemento (object):" "then the memo class" "    def __init__(self, State): Self.state= Stateclasscaretaker (object):" "then the memo management class" "    def __init__(self):Pass    defSetmemento (Self, memento):" "use a memo as a reference" "Self.memento=MementodefGetmemento (self):" "getting references from management" "        returnSelf.mementoif __name__=="__main__": Originator= Originator ("state1")    PrintOriginator.state Memento=Originator.creatememento () caretaker=caretaker () Caretaker.setmemento (memento) originator.state="State2"    Printoriginator.state Originator.setmemento (Caretaker.getmemento ())PrintOriginator.state

Results:

/users/liudaoqiang/pycharmprojects/numpy/venv/bin/python/users/liudaoqiang/project/python_project/day22_ memento/Memento_test.pystate1state2state1process finished with exit code 0

Python design mode 22nd Day "Memo mode"