65 lines
1.5 KiB
Python
65 lines
1.5 KiB
Python
"""实例：
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汤宝宝聘请了一位私人助理，帮助他管理日常事务。
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他负责记录汤宝宝的状态，以便在需要时恢复到之前的状态。
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"""
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class Tom:
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state: str
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def __init__(self, state: str) -> None:
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self.state = state
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def create_memento(self):
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m = Memento(self.state)
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print(f"汤宝宝创建了备忘录，状态为：{m.get_state()}")
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return m
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def restore_memento(self, memento):
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self.state = memento.get_state()
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print(f"汤宝宝恢复了状态：{self.state}")
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class Memento:
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__state: str
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def __init__(self, state: str) -> None:
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self.__state = state
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def get_state(self):
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return self.__state
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def set_state(self, state: str):
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self.__state = state
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class Assistant:
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__memento_list = []
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def backup(self, tom: Tom):
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self.__memento_list.append(tom.create_memento())
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def undo(self, tom: Tom):
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if not self.__memento_list:
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print("没有备份可供恢复")
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return
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memento = self.__memento_list.pop()
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print("私人助理恢复了汤宝宝的状态")
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tom.restore_memento(memento)
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if __name__ == "__main__":
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print("============= 备忘录模式 =============")
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tom = Tom("开心")
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print(f"汤宝宝的当前状态：{tom.state}")
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assistant = Assistant()
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assistant.backup(tom)
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tom.state = "生气"
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print(f"汤宝宝的当前状态：{tom.state}")
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assistant.undo(tom)
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print("\n=========== 备忘录模式结束 ===========")
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