软件架构与设计 期中考试复习

这一部分是根据老师给出的复习提纲总结的部分相关内容，但是由于架构这个东西太抽象，所以只能尽力去理解一下了。

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一想到要背这么多东西我就头疼，尽量利用已有知识理解之后串起来。

Why software architecture is important?

自己的一些思考，之所以重要是因为：

• 软件架构影响到传统软件开发的每一个环节
• 清晰的软件架构是项目正常推进的指引
• 方便重用与修改
• 易于分析和测试

Various view points

这里应该就是习题课 3 从不同视角描述系统的内容，几个视角是：

• Function View: 各个模块图，包括接口和依赖
• Information View: 展示 schema，数据模型和数据流，用状态机图来描述系统的信息模型
• Concurrency View: 软件的组件需要在哪里部署和运行
• Deployment View: 主要的软件包是什么
• Development View: 在不同地方运行时，系统是如何运行的。你会如何保证数据一致性？

What does it mean by architecture through software lifecycle?

这个题目在问什么我都有点迷糊，是不是说软件架构在软件的生命周期中的作用？还是其他什么的，大概分下面几个阶段：

• Requirements
• Design
• Coding
• Testing

不同的过程都会由架构来指引并且对架构的设计和演化有影响

Will architecture design allow creativity

这个是开放性问题，我觉得需要回答的要点是：

• 允许创新
• 但是更要尊重前人的经验
• 大部分情况下不需要全新的架构，需要在已有的基础上提高改进

Canonical elements of software architecture

这题就是概念题了，不过之前接触了这么多次，应该有一些印象，主要最后的 configuration 可能比较容易忘

• Component: computation
• Connector: communication / coordination
• Configuration: topology and constraints

Architectural styles vs Architectural patterns

这是我一直比较迷糊的概念，会着重解释一下。

• Architectural styles
  • Codify key constraints and architectural elements (components, connectors, configurations) found effective used in a family of software systems over a given time period
  • Client/Server, P2P, Object Oriented, Layered, Data-Flow, Pipe and Filter, Blackboard, Rule Based
• Architectural patterns
  • A set of architectural design decisions that are applicable to a recurring design problem, and parameterized to account for different software development contexts in which that problem appears.
  • 3-tier (Stage-Logic-Display), MVC, Sense Compute Control

Compared to styles, architectural patterns are at a coarser level of granularity (design decisions versus actual architectural elements) and are inherently more domain specific

简单来说就是 style 会有更多的细节，涉及到具体的数据、对象、管道、客户端、服务器端什么的。pattern 的话就比较虚一点，具体的界限感觉也没有多么清晰，自圆其说即可

Methods of evaluating design methods like styles and patterns

• Vocabulary,
• structural patterns
• computational model
• invariants
• common examples
• disadvantages
• specializations

我估计记不住，总体来说就是从概念，定义，模型，优势，劣势等说明，注意逻辑。

Methods of design

Greenfield design (entirely fresh start, no baggage)

• Analogy searching
• Brainstorming
• Literature searching
• Morphological Charts
• Removing Mental Blocks
• Insight from requirements/implementation

按照自己写作业的思路来回答即可

Software Connectors

4 main roles: Communication, Conversion, Facilitation, Coordination

8 main types: Event, Stream, Procedure Call, Arbitrator, Data Access, Distributor, Linkage, Adaptor

这个我真心背不下来，随缘

Benefits of first-class connectors

• Software evolution
• separation of concerns
• modularity
• pluggability

显式连接器其实是解耦的好方法，带来的好处自然就是更灵活，但是可能会有性能影响

Architectural Modeling

An architectural model is an artifact that captures some or all of the design decisions that comprise a system’s architecture

Architectural modeling is the reification and documentation of those design decisions

Important things to “get right”: Consistency, Accuracy/Precision, Ambiguity

How to choose what to model? Cost/Benefit Decision

What do we model? Structure (Architectural element), static/dynamic behaviors, functional/non-functional aspects, Views/Viewpoints

How do we evaluate modeling techniques? Scope/Purpose, Basic Elements, Style, Static/Dynamic Aspects, Dynamic Modeling, Non-functional aspects, ambiguity, accuracy/precision, viewpoints, view consistency

Modeling approaches: Generic, early ADLs, style-specific and domain-specific languages, extensible ADLs

Service Oriented Architecture

• Triangular Operational Model
• SOA Standard Stack
• SOA on Bilateral View
• SOA Solution Lifecycle
• Enterprise Service Bus
• SOA Reference Architecture – Software as a Service

ATAM

• Nine steps
• Review what you do in the group homework
• Link architectural styles with utility tree, and analyze risks and provide justifications

People, Roles and Teams

Desired skills

• Software development expertise
• Domain expertise
• Communicator
• Strategist
• Consultant
• Leader
• Technologist
• Cost estimator
• Cheerleader
• Politician
• Salesperson