Of this abstraction. The values for getRadius() or getCircumference() in the above instance might be stored directly, or they could be calculated, it won't make any difference into the caller; the setters might or won't have Uncomfortable side effects; it does not make any difference towards the caller. 近年来这方面的研究开发主要是围绕结构 、 https://luxuryapartmentsgolfcourseextension.blogspot.com/