Classes delegate responsibility to one of several helper subclasses, and you want to localize the knowledge of which helper subclass is the delegate.

委托帮助子类去实现它的责任，你想委托某一个帮助子类来局部化信息。

youdao

Classes delegate responsibility to one of several helper subclasses, and you want to localize the knowledge of which helper subclass is the delegate.

委托帮助子类去实现它的责任，你想委托某一个帮助子类来局部化信息。

youdao