Scope of OOSE. A. Starts. CMPSC 487 Lecture 01 Topics: Schach - Chap 1. The Scope of Object-Oriented Software Engineering

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1 Scope of OOSE CMPSC 487 Lecture 01 Topics: Schach - Chap 1. The Scope of Object-Oriented Software Engineering A. Starts What is dream of software developer or computer scientists? What is dream of software engineer? Want customer want?

2 B. Software Engineering (SE) Software Engineering (SE) is a discipline whose aim is the production (software) that is: Scope of software engineering is broad. Aspect of software engineering can be categorized as computer science, mathematics, economics, management, psychology, etc. It includes: Every steps of life cycle (a process for building software product) Human aspect Economic aspect Legal aspect Etc.

3 C. Historical Aspect of SE In 1967, NATO study group coined term Software Engineering (SE). In 1968, NATO software conference termed software crises. And concluded, to solve software crisis, SE should use philosophies and paradigms of engineering disciplines. In 2002 and 2004, studies from 9236 projects, conducted by a research firm called Standish Group, shows that: Now, software crisis has Maybe, software developing process has Software crisis should be called In terms of software development paradigm: ~ 1975, most software organization did not use specific techniques. 1975~1985, structured or classical paradigm were made ~ : object-oriented software engineering (OOSE) is developed (by Ivar Jacobson) and is being used.

4 D. Economical Aspect: Is better technique better? Assume that a company uses an old coding technique (old-ct), and discovered that using new coding technique (new-ct) will produce code 10% faster than using old-ct. Does using new-ct will solve software crisis? E. Human Aspect: Team Organization Assume that a product take a programmer 1 year to complete. If the product is developed by a team of 6 programmers,

5 F. Life-Cycle Model Life-cycle is a process for planning, developing, testing, and deploying a software system. a) Life-cycle model Life-cycle model is a theoretical description of what should be done Life-cycle is the actual steps performed when developing specific product b) Development-Then-Maintenance Model This is a model used in 1970s. [IEEE , 1990] It has 2 phases: c) Traditional Waterfall Life-Cycle Model Waterfall life-cycle model were popularly used until the end of the 1970s. There are many variations of this model, but by and large, development using waterfall life-cycle model goes through 6 phases 1. Requirement phase

6 2. Analysis phase 3. Design phase 4. Implementation phase 5. Postdelivery maintenance 6. Retirement Removing product from service

7 d) Maintenance Postdelivery maintenance is the modification of software product after the software has been delivered and installed on client s computer, in order to correct fault, or to improve performance or other attributes. Corrective maintenance (or software repair): Enhancement (or software update): Modern maintenance (or just maintenance): Modern maintenance or just maintenance is corrective, perfective, and adaptive activities performed at any time.

8 Note 1: SW life-cycle does not have planning phase Planning activities are carried out all through life-cycle. Note 2: SW life-cycle does not have testing phase Continual testing activity must carried out through the life-cycle. Note 3: SW life-cycle does not have documentation phase

9 G. Maintenance Aspect Importance of postdelivery maintenance Following is the plot about approx. average cost percentage of development and postdelivery maintenance: H. Requirement, Analysis, and Design Aspect (cost of fixing faults) The earlier a fault is detected and corrected, the less it costs.

10 The relative costs of fixing a fault at various phases in the software life cycle (collection from several studies) The cost of correcting a fault increases, if it is late. Why? Regression Test: Additional note:

11 I. Object-Oriented Paradigm a) History and Motivation of OO Paradigm ~ 1975, most software organization do not use specific techniques. 1975~1985, structured (or classical) paradigm were made (major breakthroughs). It includes structured system analysis, structured programming, and structured testing. Limitation of structured paradigm: 1992 ~ : object-oriented software engineering (OOSE) is developed (by Ivar Jacobson).

12 b) Strength of Object-Oriented Paradigm Information hiding Making development easier Well-designed objects are independent units. Reduce level of complexity of software product. Promote reuse c) Weakness of Object-Oriented Paradigm

13 J. Terminology Client: Developer: User: Software Internal software: Contact software: Open-source software Shrink-wrapped software, Commercial off-the-shelf (COTS) software Clickware When a programmer makes a, is the consequence of that in the code. is the observed incorrect behavior of the product as a consequence of, when executing the software product. is the amount by which a result is incorrect. is a generic term that refers to,, or. is simply euphemism for a to transfer responsibility for the mistake from the programmer to.

14 K. Definition of Object-Oriented Software Engineering (OOSE) Object-oriented software engineering is a discipline that utilizes the object-oriented paradigm to achieve the aims of software engineering. Software engineering is a discipline whose aim is: