object-oriented programming and design1 object-oriented programming and design ralph johnson...

Object-oriented programming and design 1

Object-Oriented Programming and Design

Ralph Johnson rjohnson@illinois.edu

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Goals: to learn

Principles Patterns Practices

“Object think” Frameworks / Design for reuse Reflection - using objects to implement

language

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History of Objects

Simula’67 Smalltalk 72,74,76,78,80 1985 C++ (Objective C, Object Pascal) 1986 OOPSLA 1990 COM, CORBA 1994 Design Patterns 1995 Java 2001 .NET

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Design Principles

Code to an interface rather than to an implementation Encapsulate what varies Open-closed Principle: Classes should be open to

extension and closed to modification Don’t Repeat Yourself (DRY) Single Responsibility Principle Liskov Substitution Principle: Subtypes must be

substitutable for their base types

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Smalltalk

Extreme object-oriented language Live objects Readable library Strong culture Influencial, unknown Fun!

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From Smalltalk

WIMP - Windows, Mice, Pointing Model/View/Controller Browsers CRC cards eXtreme Programming Automated refactoring tools

Smalltalk family tree Smalltalk-80

ObjectWorks ->VisualWorks 1, 2, 3, 5, 7.0-7.6 Squeak

• -> Squeak 4.1• -> Pharo• -> CUIS

Gemstone VisualAge for Smalltalk Smalltalk X, Smalltalk Agents, Dolphin

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The class First month is Smalltalk Homework, often several per week Second half of the semester is group project Reading and writing patterns

Pharo By Example. Design Patterns Domain-Driven Design

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Before next time

Get Pharo By Example www.pharobyexample.org

Read first three chapters, and follow along with Pharo

Get Pharo http://pharo-project.org Watch “Growing a Language” by Guy

Steele at http://video.google.com/videoplay?docid=-8860158196198824415#