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Mandeep Kaur, Lovely Professional University Unit 13: Class Design

Unit 13: Class Design Notes

CONTENTS
Objectives

Introduction
13.1 Design Axioms
13.1.1 Corollaries

13.2 Concept of Class Design
13.2.1 Object-oriented Design Philosophy
13.2.2 Class Visibility: Designing well-defined Public, Private and Protected
Protocols
13.2.3 Private and Protected Protocol Layers: Internal
13.2.4 Public Protocol Layer: External

13.2.5 Designing Classes: Refining Attributes
13.3 Summary
13.4 Keywords

13.5 Review Questions
13.6 Further Readings

Objectives

After studying this unit, you will be able to:

Describe the axioms of OOD
Explain the concept of class design
Discuss the types of attribute

Introduction

The class design phase determines the full definitions of the classes and associations used in the
implementation, as well as the interfaces and algorithms of the methods used to implement
operations. The object-designer works to implement the objects discovered during analysis
phase. All the operations identified during analysis are expressed as algorithms, with complex
operations expressed as internal operations. You need to apply axioms to the design classes,
their attributes, structures, associations, protocols and methods. This step includes refinement
and completion of static UML class diagram done by adding details to UML class diagram which
includes performing the activities:
Attributes should be refined
Protocols and methods should be designed by using UML activity diagram to represent
the method algorithm

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