摘要： When you are building a house, you may choose to install a home entertainment system. It is possible to buy a single unit that includes everything: television screen, tuner, VCR, DVD player, and speakers. Such a system is easy to install and works great if it meets your needs. A one-piece unit is no 阅读全文

摘要： 本章开篇综述： 1.A component is a logical, replaceable part of a system that conforms to and provides the realization of a set of interfaces. 组件的目的是通过可替换的方法，实现相同的接口，构建灵活的系统。 2.Good components define crisp abstractions with well-defined interfaces, making it possible to easily replace older components ... 阅读全文