通过面向对象的编程和接口设计原则，您只需使用新的ContactJdoDAO替代原始的ContactDAOMock。

Due to the wonders of object-oriented programming and the principles of design by interface, you can simply replace your original ContactDAOMock with the new ContactJdoDAO.

youdao

另一个对象设计原则(封装)也适用于设计服务接口。

Another object design principle, that of encapsulation, also applies to designing service interfaces.

youdao

最值得注意的结果是服务接口之外非常不灵活，因为模块设计、信息隐藏和逻辑结构原则均未得到遵循。

The most notable consequence is the inflexibility beyond the service interface since modular design, information hiding and logical structuring principles are all violated.

youdao