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memento.py
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memento.py
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# -*- coding: utf-8 -*-
class Originator():
class Memento():
''' '''
def __init__(self, stateToSave):
self.state = stateToSave
def getSavedState(self):
return self.state
def __init__(self, state=None):
self.state = state
def set(self, state):
print "Originator: Setting state to %s" % state
self.state = int(state)
def saveToMemento(self):
print "Originator: Saving to Memento."
return self.Memento(self.state)
def restoreFromMemento(self, m):
if isinstance(m, self.Memento):
self.state = m.getSavedState()
print "Originator: State after restoring from Memento: %s" % self.state
class Caretaker():
def __init__(self):
self.savedStates = list()
def addMemento(self, m):
self.savedStates.append(m)
def getMemento(self, idx):
return self.savedStates[idx]
def main():
caretaker = Caretaker()
originator = Originator()
originator.set("State1")
originator.set("State2")
caretaker.addMemento( originator.saveToMemento() )
originator.set("State3")
caretaker.addMemento( originator.saveToMemento() )
originator.set("State4")
originator.restoreFromMemento( caretaker.getMemento(1) )
if __name__ == '__main__':
main()