2022哈工大软件构造我的学习笔记(1)

一、软件多维视图

软件多维视图包括moment/period，build/run time,code/component level三个维度共 $2^{3}$ 个视图。

1.build time下关注：

Code-level view：source code源代码 ---- how source code are logically organized by basic program blocks such as functions, classes, methods, interfaces, etc, and the dependencies among them 即代码的逻辑组织。

Component-level view：architecture结构 ---- how source code are physically organized by files, directories, packages, libraries, and the dependencies among them 即代码的物理组织

Moment view: what do source code and component look like in a specific time 特定时刻的软件形态

Period view: how do they evolve/change along with time 软件形态随时间的变化

2.run time下关注：

Code-level view: source code ---- what do the in-memory states of an executable program look like and how do program units (objects, functions, etc) interact with each other? 代码层面：逻辑实体在内存中如何呈现？

Component-level view: architecture ---- how are software packages deployed into physical environment (OS, network, hardware, etc) and how do they interact? 构件层面：物理实体在物理硬件环境中如何呈现？

Moment view: how do programs behave in a specific time 逻辑/物理实体在内存/硬件环境中特定时刻的形态如何？

Period view: how do they behave along with time 逻辑/物理实体在内存/ 硬件环境中的形态随时间如何变化？

各维度视图包含的内容在历年考试题中是考过的，需要记住这张图：

二、内部质量属性和外部质量属性

External quality factors affect users 外部质量因素影响用户

Internal quality factors affect the software itself and its developers内部质量因素影响软件本身和它的开发者

External quality results from internal quality 外部质量取决于内部质量

这部分每年都会占比一部分的小分：

外部质量属性包括：Correctness正确性、Robustness健壮性、Extendibility可拓展性、Reusability可复用性、Compatibility兼容性、Efficiency效率、Portability (可移植性)、Ease of use (易用性)、Functionality功能性、Timeliness (及时性)

内部质量属性包括：Source code related factors such as Lines of Code (LOC), Cyclomatic Complexity, etc 、 Architecture-related factors such as coupling, cohesion, etc。源代码相关因素，如代码行（LOC），环形复杂性等，架构相关因素，如耦合，内聚等。Readability可读性 ▪ Understandability 易于理解▪ Clearness清楚 ▪ Size大小

三、数据类型

基本数据类型：小写的，如int、long、boolean、double、char等

对象数据类型：大写的，能放进<>里的，如String、BigInteger等

可变的能改变地址空间内的值，不可变的只能改变指向的地址空间。