If you’re an ABAP application developer with basic ABAP programming skills, this book will teach you how to think about writing ABAP software from an object-oriented (OO) point of view, and prepare you to work with many of the exciting ABAP-based technologies in ABAP Objects (release 7.0).

Using this comprehensive book as your guide, you can make the switch to object-oriented programming effectively, while bringing your skills up-to-date. You’ll learn all essential OO concepts, and see examples from real-world projects. Object initialization, inheritance, polymorphism, exception handling, unit testing, and much more are demystified here, plus, you’ll explore enhanced techniques and tools in ABAP 7.0. The book doesn't spend too much time teaching basic syntax, but rather concentrates on teaching object-oriented development – this is your chance to successfully explore object-oriented programming with ABAP Objects.

As a bonus, at the end of each chapter, brief tutorials show you how to express your object-oriented designs using the Unified Modeling Language (UML).

Highlights

• Working with Objects
• Encapsulation and Implementation
• Hiding
• Object Initialization and Cleanup
• Inheritance and Polymorphism
• Component-Based Design Concepts
• Error Handling with Exceptions
• Unit Testing with ABAP Unit
• Working with the SAP List Viewer
• ABAP Object Services
• Working with XML
• Debugging Objects

About the Author(s)

James Wood is the founder and principal consultant of Bowdark Consulting, Inc., an SAP NetWeaver consulting and training organization. With more than seven years of experience as a software engineer, James specializes in custom development in the areas of ABAP Objects, Java/J2EE, SAP NetWeaver Process Integration, and the SAP NetWeaver Portal.

Table of Contents

... Introduction ... 15


1 ... Introduction to Object-Oriented Programming ... 23
... 1.1 ... The Need for a Better Abstraction ... 23
... 1.2 ... Classes and Objects ... 24
... 1.3 ... Establishing Boundaries ... 27
... 1.4 ... Reuse ... 29
... 1.5 ... Object Management ... 33
... 1.6 ... UML Tutorial: Class Diagram Basics ... 33
... 1.7 ... Summary ... 39


2 ... Working with Objects ... 41
... 2.1 ... Syntax Overview ... 41
... 2.2 ... Creating and Using Objects ... 52
... 2.3 ... Building Your First Object-Oriented Program ... 64
... 2.4 ... Getting Started with the Class Builder ... 71
... 2.5 ... Case Study: Working with Regular Expressions ... 82
... 2.6 ... UML Tutorial: Object Diagrams ... 84
... 2.7 ... Summary ... 86


3 ... Encapsulation and Implementation Hiding ... 89
... 3.1 ... Lessons Learned from the Procedural Approach ... 89
... 3.2 ... Data Abstraction with Classes ... 94
... 3.3 ... Defining Component Visibilities ... 95
... 3.4 ... Hiding the Implementation ... 101
... 3.5 ... Designing by Contract ... 102
... 3.6 ... UML Tutorial: Sequence Diagrams ... 103
... 3.7 ... Summary ... 105


4 ... Object Initialization and Cleanup ... 107
... 4.1 ... Creating Objects ... 107
... 4.2 ... Controlling Object Initialization with Constructors ... 111
... 4.3 ... Taking Control of the Instantiation Process ... 117
... 4.4 ... Garbage Collection ... 121
... 4.5 ... Tuning Performance ... 122
... 4.6 ... UML Tutorial: State Machine Diagrams ... 125
... 4.7 ... Summary ... 126


5 ... Inheritance ... 127
... 5.1 ... Generalization and Specialization ... 128
... 5.2 ... Inheriting Components ... 133
... 5.3 ... The Abstract and Final Keywords ... 140
... 5.4 ... Inheritance Versus Composition ... 145
... 5.5 ... Using the Refactoring Assistant ... 148
... 5.6 ... UML Tutorial: Advanced Class Diagrams Part I ... 150
... 5.7 ... Summary ... 153


6 ... Polymorphism ... 155
... 6.1 ... Object Reference Assignments Revisited ... 155
... 6.2 ... Dynamic Method Call Binding ... 160
... 6.3 ... Interfaces ... 163
... 6.4 ... UML Tutorial: Advanced Class Diagrams Part II ... 180
... 6.5 ... Summary ... 182


7 ... Component-Based Design Concepts ... 183
... 7.1 ... Understanding the SAP Component Model ... 183
... 7.2 ... The Package Concept ... 185
... 7.3 ... UML Tutorial: Package Diagrams ... 197
... 7.4 ... Summary ... 199


8 ... Error Handling with Exceptions ... 201
... 8.1 ... Lessons Learned from Prior Approaches ... 201
... 8.2 ... The Class-Based Exception Handling Concept ... 203
... 8.3 ... Dealing with Exceptions ... 205
... 8.4 ... Raising and Forwarding Exceptions ... 210
... 8.5 ... Creating Exception Classes ... 219
... 8.6 ... UML Tutorial: Activity Diagrams ... 229
... 8.7 ... Summary ... 231


9 ... Unit Testing with ABAP Unit ... 233
... 9.1 ... ABAP Unit Overview ... 234
... 9.2 ... Creating Unit Test Classes ... 237
... 9.3 ... Case Study: Creating a Unit Test in ABAP Unit ... 241
... 9.4 ... Executing Unit Tests ... 244
... 9.5 ... Evaluating Unit Test Results ... 246
... 9.6 ... Moving Toward Test-Driven Development ... 247
... 9.7 ... UML Tutorial: Use Case Diagrams ... 248
... 9.8 ... Summary ... 253


10 ... Working with the SAP List Viewer ... 257
... 10.1 ... Overview of the SAP Control Framework ... 257
... 10.2 ... Overview of the ALV Object Model ... 260
... 10.3 ... Getting Started with the Flight Query Report ... 261
... 10.4 ... Event Handling with the ALV Object Model ... 271
... 10.5 ... UML Tutorial: Communication Diagrams ... 275
... 10.6 ... Summary ... 277


11 ... ABAP Object Services ... 279
... 11.1 ... Object-Relational Mapping Concepts ... 280
... 11.2 ... Persistence Service Overview ... 280
... 11.3 ... Building Persistent Classes ... 286
... 11.4 ... Working with Persistent Objects ... 293
... 11.5 ... UML Tutorial: Advanced Sequence Diagrams ... 298
... 11.6 ... Summary ... 301


12 ... Working with XML ... 303
... 12.1 ... XML Overview ... 303
... 12.2 ... XML Processing Concepts ... 309
... 12.3 ... Case Study: Developing a Reading List ADT ... 311
... 12.4 ... Case Study: Building an XML Document ... 314
... 12.5 ... Case Study: Reading an XML Document ... 320
... 12.6 ... UML Tutorial: Advanced Activity Diagrams ... 325
... 12.7 ... Summary ... 327


13 ... Where to Go From Here ... 329


A ... Debugging Objects ... 333
... A.1 ... Debugging Objects Using the Classic ABAP Debugger ... 333
... A.2 ... Debugging Objects Using the New ABAP Debugger ... 340


B ... The Author ... 343