Subject參數問題
/* ????這里為什么不直接把ConcreteSubject當參數呢??? */ public?void?update(Subject?subject)?{ ???????observerState?=?((ConcreteSubject)subject).getSubjectState(); }
/* ????這里為什么不直接把ConcreteSubject當參數呢??? */ public?void?update(Subject?subject)?{ ???????observerState?=?((ConcreteSubject)subject).getSubjectState(); }
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