Chapter 7 Object-Oriented Design

1.Responsibility Driven Design（责任驱动设计）

2. Behavior（行为） and State（状态）  Instances（实例） and Classes（类）  Coupling（耦合） and Cohesion（内聚）  Interface（接口） and Implementation（实现）

3.component（组件）entity（实体）

4.collaborators（协作者）

5.scenarios（场景）.

6.Characteristics of Components

Behavior and State Instances and Classes Couplingand Cohesion Interfaceand Implementation

7.Cohesion（内聚） is the degree to which the responsibilities of a single component form a meaningful unit.
Couplingis（耦合） the degree to which the ability to fulfill a certain responsibility depends upon the actions of another component.

8.The interface（接口） describes what a software component can perform.
The implementation（实现）describes how a component goes about completing a task.