《uml课件Lect1-Evolution Object Model-Unified Process》由会员分享，可在线阅读，更多相关《uml课件Lect1-Evolution Object Model-Unified Process（73页珍藏版）》请在金锄头文库上搜索。
1、Lecture 1. Lecture 1. The Evolution of the Object Model and Unified Development Unified Development ProcessProcessObject Oriented Technology and System Modeling面向对象技术与系统建模 Instructor: Yushan Sun Spring Term 2013内容提要： 1. The Evolution of the Object Model 面向对象模型的进化(Grady Booch Book 2.1) 2. Review of E
2、arlier Software Development Models 早期软件开发模型回顾 (Mark Priestley Book) 3. 3. The Unified Process The Unified Process 统一过程模型统一过程模型 (Mark Priestley Book) 4. The Use of UML in the Unified Process1. The Evolution of the Object Model (Grad Book 2.1) 面向对象开发 继承了 其它 语言的 精髓 OO development is not a radical depar
3、ture from earlier approaches. Indeed, it is founded in the best ideas from prior technologies. 本节研究编程语言的进化，以便理解面向对象技 术 In this section, we will examine the evolution of the programming languages to help us understand the foundation and emergence of OO technology. 从历史上看，我们注意到两种潮流：从小规模编 程到大规模编程的转变；高级编
4、程语言的进化 As we look back on the history of software engineering. We notice two sweeping trends: The shift in focus from programming-in-the- small to programming-in-the-large The evolution of high-order programming languages 大多数工业软件系统都比较大且复杂 Most new industrial-strength software systems are larger and
5、more complex than their predecessors were even just a few years ago. The Generations of Programming Languages 编程语言的断代 Programming languages generations are arranged according to the language features they first introduced First-generation languages (19541958) FORTRAN I: Mathematical expressions ALGO
6、L 58: Mathematical expressions 特点：数学表达式；科学、工程 Second-generation languages (19591961) FORTRAN II: Subroutines, separate compilation ALGOL 60: Block structure, data types COBOL: Data description, file handling 特点：算法抽象（子程序），文件处理，商业应 用000100 IDENTIFICATION DIVISION. 000200 PROGRAM-ID. HAPPYNEWYEAR. 0003
7、00 100000 PROCEDURE DIVISION. 100100 100200 MAIN-LOGIC SECTION. 100300 BEGIN. 100400 DISPLAY “ “ LINE 1 POSITION 1 ERASE EOS. 100500 DISPLAY “Happy New Year!“ LINE 15 POSITION 10 100600 STOP RUN. 100700 MAIN-LOGIC-EXIT. 100800 EXIT. The following is a piece of simple COBOL code，to show the features
8、of unstructured programming.所有代码都写在一个文件中。分成几段：包括过程区、主逻辑区等过程区主逻辑区 Third-generation languages (19621970) PL/1: FORTRAN + ALGOL + COBOL ALGOL 68: Rigorous successor to ALGOL 60 Pascal: Simple successor to ALGOL 60 Simula: Classes, data abstraction 特点：支持数据抽象 The generation gap (19701980) Many different
9、languages were invented, but few endured. However, the following are worth noting: C: efficient; small executables (1973 AT heavy Pascal influence 特点：支持面向对象编程、设计、分析 Emergence of frameworks (1990today) Much language activity, revisions, and standardization have occurred, leading to programming framew
10、orks. Visual Basic: Eased development of the graphical user interface J2EE: Java-based framework for enterprise computing .NET: Microsofts object-based framework 特点：支持大规模软件开发Topology of 1st-and Early 2nd-Generation Languages (第1代第2代早期语言的拓扑结构) In Fig 2-1, we see the topology of most 1st- and early 2n
11、d-generation programming languages. By topology, we mean the basic physical building blocks of the language and how those parts can be connected. FORTRAN 和 COBOL语言的基本建筑块是子程 序 In this figure, we see that, for languages such as FORTRAN and COBOL, the basic physical building block of all applications i
12、s the subprogram.Figure 21 The Topology of First- and Early Second-Generation Programming Languagessubprogramsglobal data子程序子程序子程序子程序箭头 代表 依赖扁平的物理结构 ： 1)全局变量 2)子程序 扁平结构设计 Applications written in these languages exhibit a relatively flat physical structure, consisting only of global data and subprogr
13、ams. 缺点1：程序缺陷引起波浪传导效应；主要是全 局变量可以被任何代码修改 An error in one part of a program can have a devastating ripple effect across the rest of the system because the global data structures are exposed for all subprograms to see. 缺点2：当大系统需要修改的时候，很难保持原 设计的完整性 When modifications are made to a large system, it is di
14、fficult to maintain the integrity of the original designTopology of Late 2nd- Early 3rd - Generation Languages (第2代后期第3代早期语言的拓扑结 构) 在60年代中期，抽象被认为是问题与计算机的中介 By the mid-1960s, programs were being recognized as important intermediate points between the problem and the computer. 最早的软件抽象: 过程抽象(出于实用的目的)；子
15、程 序没有被看成是抽象，而仅仅视为一种省力的手段； The first software abstraction, now called the procedural abstraction, grew out of this pragmatic view of software. Originally, subprograms were not appreciated as abstractions. Instead, they were seen as labor- saving devices. 很快地，人们开始珍视为抽象的程序功能 Very quickly, subprograms were appreciated as a way to abstract program functions. 将子程序作为抽象机制的3个后果 Using subprograms as an abstraction mechanism had three important consequences. 1) 支持参数传递机制语言产生了Languages were invented that supported a variety of parameter-passing mechanisms. 2) 奠定了结构化编程的基础The foundations of structured progr
