Software Design 2e - DIM

chapter 16341Designing with Objects16.1 The ‘object concept’ 16.3 Object-Oriented frameworks16.2 Design practices for the 16.4 Object-based designobject-oriented paradigm 16.5 Object-Oriented designObjects with a capital ‘O’ have occupied a position centre-stage in softwaredevelopment since the early 1980s. The word ‘object’ appears in manyconference titles. The literature on most aspects of their form, developmentand use is voluminous, with the possible, and rather significant,exception of empirical studies. In addition, almost all programming languagesdeveloped since 1990 have had object-oriented features, andsuch features have also been retro-fitted to some older programminglanguages! Indeed, object-oriented programming is widely accepted asan important and powerful way of creating software systems.Despite all of this, the task of designing with objects remains a significantproblem. Analysis and design methods have proliferated and beenunified; the pattern concept described in Chapter 10 has been devisedto help address the problem; and further mechanisms such as frameworkshave been introduced. However, useful as all of these have been,designing with objects remains a complex cognitive task.This chapter addresses the challenging question of how we can design systemswith objects using design methods. It examines the concept of theobject; reviews the conceptual issues it raises for design activities; andthen describes some of the approaches to designing with objects thathave been developed.