객체지향시스템 연구실 1 THE OBJECT-ORIENTED TECHNOLOGY: An Executive Summary 서울대학교 컴퓨터공학부 객체지향시스템 연구실 교수 김형주

객체지향시스템 연구실 2 OBJECT-ORIENTED PARADIGM OBJECT-ORIENTED PARADIGM u Historical Background u Object-Oriented Concepts u Core Elements u Encapsulation u Message Passing u Inheritance u Late Binding u Method Combination u Benefits & Problem

객체지향시스템 연구실 3 HISTORICAL BACKGROUND (1) u Root: SIMULA (1966) u Dahl & Nygarrd 66 CACM paper u Simulation language u Notion of Class u SMALLTALK ( ) u Xerox PARC, Adele Goldberg u The first substantial, interactive, display-based implementation u An integrated programming language environment u User interface u Class library

객체지향시스템 연구실 4 HISTORICAL BACKGROUND (2) u AI Community (1980’s) u AI Language Side u Actor: Concurrent Objects(Carl Hewitt at MIT) u Flavors(MIT), Loops(XEROX): OO-Programming in Lisp u AI Application Development Tools u Strobe(Schlumberge) u KEE(Intellicorp) u Programming Language Community (1980’s) u Abstract Data Type, Encapsulation u Alphard, CLU, ADA

객체지향시스템 연구실 5 HISTORICAL BACKGROUND(3) u Observations u 1970’s: Age of Structured Programming u 1980’s: Transition Age from Structured Programming to Object-Oriented Programming u 1990’s: Age of Full-Fledged Object-Oriented Programming u 2000’s: Object Technology for WWW and EC

객체지향시스템 연구실 6 HISTORICAL BACKGROUND(4) u Why took so long? Why after 1990! u Simula67: designed for simulation people u Smalltalk: company confidential(XEROX) u Smalltalk requires powerful windowing facility as well as powerful hardware u Now! u Most software products are following the OO paradigm u OO Dedicated conferences: OOPSLA, ECOOP, OODB conferences, etc. u OO Journals: JOOP u Many conferences of systems area have OOP session or track

객체지향시스템 연구실 7 The Object-Oriented Technology: Executive Summary u Buzzword u to used to promote their products u Silver Bullet u will solve the productivity crisis u Main Conclusion! 1. Object-Oriented Technology is a key feature of any Silver Bullet 2. Object-Oriented Systems will play a central role in all computer-related technologies in 2000s

객체지향시스템 연구실 8 What is Object-Oriented System?(1) u Object-Oriented Technology: u A way to develop and package Software that draws heavily from common experience and the manner in which real world objects relate to each other u Object-Oriented Systems: u All programming languages, tools and methodologies that support Object-Oriented Technology

객체지향시스템 연구실 9 What is Object-Oriented System?(2) u Features of Object-Oriented Technology 1. Object u data u procedure 2. Message 3. Class 4. Hierarchy u cf. Object-Based System

Consumer sees only definition Supplier is responsible for Implementation Sequence : next previous : Array : add find : Set : find add : Objects are a new way of packaging software

객체지향시스템 연구실 11 Object-Oriented Systems:Class Hierarchy u Class hierarchy of Envelope Containers Mailboxes Envelopes File Folders Business Envelopes Business Envelopes Air Mail Envelopes Air Mail Envelopes

객체지향시스템 연구실 12 Benefits of Object-Oriented Systems(1) 1. Improve Productivity 2. Model Complexity 3. Designed for Change 4. Reusable 5. Maintainable

객체지향시스템 연구실 13 Benefits of Object-Oriented Systems(2) u The use of objects as basic modules assists the designer to model complex real-world systems u The flexibility of object-oriented code allows a rapid response to changes in their requirements u The reuse of standard components reduces both the development time for new applications and the volume of code generated u The increased maintainability of software makes it more reliable and reduces maintenance costs

객체지향시스템 연구실 14 Problems * Performance u binding between messages and corresponding procedures u garbage collection u swap overhead if system contains many small objects * Lack of formal background yet!