UML期末复习笔记

UML

概述

背景

• 软件危机 software crisis

  • projects running over-budget
  • projects running over-time
  • software was very inefficient
  • software was of low quality
  • software often did not meet requirements
  • projects were unmanageable and code is difficult to maintain

• solution to software crisis

  • software complexity is inherent

  • reduce and control the complexity of software

    basic method of controlling software complexity

    • divide
    • abstract
    • modularization 模块化
    • information hiding

软件生命周期 software life cycle

UML 在软件生命周期的每个阶段均有应用

• requirement analysis 需求分析

  use case diagram

• software design 软件设计

  class diagram

  interaction diagram

  state machine diagram

  activity diagram

• coding/programming 实现

  class diagram

• testing/debug 测试

  class diagram

  component diagram

  deployment diagram

• running/maintenance 运行维护

  deployment diagram

软件过程模型 software process model

瀑布模型 waterfall model

线性、顺序模型

易于理解与使用

每个过程都有详细、具体的可交付代码以及反馈

对于小型、需求易于理解的项目比较友好

但缺乏灵活性

不能适应变化的需求

原型模型 prototype model

• 步骤

  • 确认基本需求
  • 开发初步原型
  • 反馈回顾原型
  • 重构、拓展原型

• 特点

  • 循环
  • 引入客户评价
  • 时时改进、修改

  与客户关系紧密

增量模型 incremental model

模块化，不断加入总的工程中

螺旋模型 spiral model

增量模型加入风险评估

• 每个螺旋拥有四个过程
  • planning
  • risk analysis
  • engineering
  • evaluation

软件工程方法及技术

structured method

重视数据流

• 优点

  易于掌控

  方法更为成熟，有更多支持的工具

• 缺点

  开发效率低，复用性差

object-oriented method

系统由对象构成

对象间通信

对象既包含数据又包含行为

对象被分为类，各个类之间建立继承关系

UML对面向对象支持比较好

object and instance-对象和实例

class-类

encapsulation-封装

inheritance-继承

polymorphism-多态

message passing-通信

RUP rational unified process

六个最佳方案

• develop iteratively迭代式开发
• manage requirements 需求管理
• use components 组件化
• model visually 模型可视化
• verify quality
• control changes

core workflow工作流

core process workflows

• business modeling 商业建模
• requirements 需求
• analysis & design 分析与设计
• implementation 实现
• test 测试
• deployment 部署

core supporting workflows

• configuration & change management 配置 & 变化管理
• project management 项目管理
• environment 环境

four phases

• inception
• elaboration
• construction
• transition

RUP 4+1 view model

• logical view
• development view
• physical view
• process view
• +1——scenarios

UML Unified Modeling Language

basic building block基本构造块

• thing 事物
  • structural things
    • class
    • interface
    • collaboration
    • use case
    • active class
    • component
    • artifact & node
  • behavioral things
    • interaction
    • state machine
    • activity
  • grouping things
    • package
  • annotational things
    • note
• relationship 关系
  • dependency
  • association
  • generalization
  • realization
• diagram 图
  • structural diagrams
    • class diagram
    • component diagram
    • object diagram
    • deployment diagram
    • package diagram
    • composite structure diagram
    • profile diagram
  • behavior diagram
    • activity diagram
    • use case diagram
    • state machine diagram
    • interaction diagram
      • sequence diagram
      • communication diagram
      • interaction overview diagram
      • timing diagram

rule 规则

• name
• scope
• visibility
• integrity
• execution

common mechanism

• specification
• adornment
• common division
• extensibility mechanism
  • stereotypes
  • tagged values
  • constraints

Use case modeling 用例建模

requirements technology

two types of requirements

• functional requirements
• non-functional requirements

three types of requirements technology

• user story in extreme programming(XP)

  as a , I want so that

• feature description in feature-driven development(FDD)

  the <by|for|of|to> a(n)

• use case in rational unified process(RUP)

  use case is the basic characteristics

  use case driven software development process

  • use case model

    use case diagram

  • analysis model

    class diagram, package diagram

  • design model

    class diagram, package diagram, object diagram, component diagram

  • deployment model

    component diagram, deployment diagram

  • test model

use case

definition

use cases are a means to capture(采集、捕捉) the requirements of systems.

A use case is a specification(规范、规格) of behavior

use cases define interactions between external actors and the system to attain particular goals

name

every use case must have a name that distinguishes it from other use cases

a name is a textual string(文本字符串)

in practice, use case names are short active verb phrases naming some behavior found in the vocabulary of the system you are modeling

elements of use case diagram

• use case

• actor

  a human, a hardware device, even another system plays with a system

  actors之间可以有泛化关系

  

• relationship

  参与者之间为泛化关系

  参与者与用例为关联关系

  用例之间有泛化关系、include、extend（后两种为依赖关系的特殊形式）

  included 用例不能单独存在（虚线+线箭头，指向被include）

  extended 用例可以单独存在（虚线+线箭头，指向base）

  

class diagram

class definition

一类具有相同的属性、方法、关系、语义的对象的集合的描述。

relationships 关系

斜体表示抽象类

依赖

泛化

聚合

组合

关联

实现

three stereotypes of class

• boundary class
• entity class
• control class

three perspectives of class diagram

• conceptual 概念层
• specification 说明层
• implementation 实现层

principles of object oriented class design

• open closed principle(OCP)开闭原则

  对扩展开放，对修改关闭

  在需求变化时，可以在不修改源代码或者二进制代码的前提下，扩展模块的功能，使其满足新的需求

• liskov substitution principle(LSP)里氏替换原则

  继承必须保证父类的性质不被改变

  子类可以扩展父类原有的功能，但不能改变父类原有的功能

  如：几维鸟不会飞，故不能继承自会飞的鸟类

• dependency inversion principle(DIP)依赖倒置原则

  高层模块不应该依赖底层模块，两者都应该依赖其抽象，抽象不应该依赖细节，细节应该依赖抽象。

  核心思想：要面向接口编程，不要面向实现编程。

• interface segregation principle(ISP)接口分离原则

  一个类对另一个类的依赖应该建立在最小的接口上

activity diagram 活动图

constituent elements of activity diagram

• initial node
• final node
• activity node
• control flow
• decision node and guard expression
• merge node
• fork node and join node

state machine diagram 状态机图

concept of the state

a state of an object is a period of time during which it satisfies some condition, performs some activity, or waits for some event

• name
• entry/exit effects
• internal transitions
• substates
• deferred events

constituent elements of state machine diagram

• initial state and final state
• transition
  • source and target state
  • event trigger
  • guard condition
  • effect

object diagram&package diagram 对象图&包图

representation of objects

• a name is a textual string

包为分组事物

owned elements in package diagram

• classes
• interfaces
• components
• nodes
• collaborations
• use cases
• diagrams
• even other packages

relationships between package

dependency

• «import»

  code——using, import

• «access»

  能访问另一个包中的信息，但命名空间没有合并

• «trace»

  包的发展历史

generalization

principles of package design

• the release reuse equivalency principle(REP)重用发布等价原则

  重用粒度就是发布粒度。一个包中的类要么都是可以重用的，要么就都不可以重用。

• the common reuse principle(CRP)共同重用原则

  一个包中的所有类应是共同重用的

• the common closure principle(CCP)共同封闭原则

  一个变化如果对一个包中的类产生影响，则对整个包中的所有类产生影响，对其他包中的类不产生影响

• the acyclic dependencies principle(ADP)无环依赖原则

  包间的依赖关系不允许存在环

interaction diagram 交互图

sequence diagram 顺序图

constituent elements of sequence diagram

• object
• lifeline
• focus of control
• message

communication diagram 通讯图

constituent elements of communication diagram

• object
• link
• message

comparison between sequence and communication diagram

顺序图强调消息传递的时间顺序，通讯图强调参加一个交互的对象的组织结构

因为均来自于UML的元模型的同一信息，所以他们在语义上是等价的

timing diagram（强调时间特性）

interaction overview diagram（顺序图+活动图）

component diagram构件图

展现构件间的组织结构、依赖关系

强调系统的静态实现、运行

比类图更抽象

deployment diagram部署图

forward and reverse engineering

• forward engineering

  图–>代码

• reverse engineering

  代码–>图