Object-Oriented Design

Transcription

1 Object-Oriented Design Peter Coad and Edward Yourdon Technische Hochschule Darmstadt FACHBKREICH INFORMATIK BIBLIOTHEK Inventar-Nr.:...A.Q.HA&. Sachg biete:.../??/.4, Standort: YOURQDN PRESS PRENTICE HALL BUILDING ENGLEWOOD CLIFFS, NJ 07632

2 Contents Preface Acknowledgments 0 Introduction History Method and Tool Future Advances 1 Improving Design Basic Terminology Principles for Managing Complexity Abstraction Encapsulation Inheritance Association Communication with Messages Pervading Methods of Organization Scale Behavior Classification OOD and the Impact of Prototyping Reasons for Prototyping Advice^ for OOD Prototyping The Key Objectives of OOD Improve Productivity Increase Quality Elevate Maintainability Motivations and Benefits of OOD 2 Developing the Multilayer, Multicomponent Model Discovering a Model A Continuum of Representation The Problem A Solution Some Major Implications Five Layers, Five Activities Four Components, Four Activities xiii XV l vii

3 viii Contents 2.5 Definitions and Notations Definitions and Notations Class-&-Object Definitions and Notations Structure Definitions and Notations Subject Notation Attribute (and Instance Connection) Notation Service (and Message Connection) Notation Summary 34 3 Designing the Problem Domain Component What Problem Domain Component The Approach What It Is Not The Approach What It Is Why Problem Domain Component How Problem Domain Component Apply OOA Use OOA Results and Improve Them Use OOA Results and Add to Them Example Sensor Monitoring System Example OOA Tool 53 4 Designing the Human Interaction Component What Human Interaction Component Why Human Interaction Component How Human Interaction Component Classify the Humans Describe the Humans and Their Task Scenarios Design the Command Hierarchy Design the Detailed Interaction Continue to Prototype Design the HIC Classes Design, Accounting for Graphical User Interfaces Example Sensor Monitoring System Example OOA Tool 70 5 Designing the Task Management Component What Task Management Component Why Task Management Component How Task Management Component Identify Event-Driven Tasks Identify Clock-Driven Tasks 74

4 Contents ix Identify priority Tasks and Critical Tasks Identify a Coordinator Challenge Each Task Define Each Task Example-Sensor Monitoring System Example OOA Tool 79 6 Designing the Data Management Component What Data Management Component Why Data Management Component How Data Management Component Data Management Approaches Assessing Data Management Tools Designing the Data Management Component Example Sensor Monitoring System Example OOA Tool 87 7 Applying OOD with OOPLs (or Less Than an OOPL) Being Utterly Pragmatic about Languages The Language Impact on OO Development Evaluating Language Syntax and Features Evaluation Criteria Syntax and Features C++ and Object Pascal Syntax and Features Smalltalk and Objective-C Syntax and Features Eiffel Syntax and Features Ada Syntax and Features Procedural Languages Selecting OOPLs Which OOPLs Will Dominate? Reusability across OOA to OOD to OOPLs Class Library and Development Environment Other Issues Applying OOD Criteria Introduction: What and Why Coupling Interaction Coupling Inheritance Coupling Cohesion Service Cohesion 134

5 x Contents Class Cohesion Generalization-Specialization Cohesion Reuse Why Does It Matter Why Aren't People Doing It? Levels of Reusability Organizational Approaches to Reusability Additional Criteria Clarity of Design Generalization-Specialization Depth Keeping Objects and Classes Simple Keeping Protocols Simple Keeping Services Simple Minimizing Design Volatility Minimizing Overall System Size Ability to "Evaluate by Scenario" Evaluation by "Critical Success Factors" Recognized Elegance in the Design Final Comments 9 Selecting CASE for OOD Expanding Case What's Needed for OOD Notation Layers Components Auto-Tracking Features Advanced Features Model Checks What's Available Additional Considerations 10 Getting Started with OOD Another Silver Bullet? Is this the Time to Start Using OOD? Is the Object-Oriented Paradigm Mature? Is There a Good Obiect-Oriented Implementation Technology? Is the Development Organization 157 Sophisticated Enough?

6 Contents xi Is the Organization Building Systems That 158 Will Exploit Object-Oriented Techniques? 10.3 Revolution Versus Evolution How to Get Started with OOD Conclusion 161 A OOA/OOD Notation Summary 162 B OOA Strategy Summary 164 C OOD Strategy Summary 171 Bibliography 182 Index 190