... Preface ... 17

... Who This Book Is For ... 17

... How This Book Is Organized ... 17

... Acknowledgments ... 19

... Conclusion ... 21

1 ... Introduction ... 23

1.1 ... What Is Clean ABAP? ... 23

1.2 ... How to Get Started with Clean ABAP ... 26

1.3 ... How to Handle Legacy Code ... 26

1.4 ... How to Check Code Automatically ... 28

1.5 ... How Does Clean ABAP Relate to Other Guides? ... 29

1.6 ... How to Engage with the Clean ABAP Community ... 30

1.7 ... Summary ... 31

2 ... The ABAP Language ... 33

2.1 ... Mind Legacy Code ... 33

2.2 ... Mind Performance ... 35

2.3 ... Prefer Object Orientation to Procedural Programming ... 37

2.4 ... Favor Functional Language Constructs over Procedural Language Constructs ... 43

2.5 ... Avoid Obsolete Language Elements ... 46

2.6 ... Use Design Patterns Wisely ... 48

2.7 ... Summary ... 50

3 ... Classes and Interfaces ... 51

3.1 ... Object Orientation ... 51

3.2 ... Scope and Visibility ... 76

3.3 ... Constructors ... 83

3.4 ... Summary ... 93

4 ... Methods ... 95

4.1 ... Object-Oriented Programming ... 95

4.2 ... Parameters ... 102

4.3 ... Method Body ... 115

4.4 ... Calling Methods ... 125

4.5 ... Summary ... 130

5 ... Names ... 133

5.1 ... Good Naming ... 133

5.2 ... ABAP Peculiarities ... 138

5.3 ... Affixes: Prefixes, Suffixes, and Infixes ... 140

5.4 ... Dealing with Legacy Code ... 142

5.5 ... Summary ... 143

6 ... Variables and Literals ... 145

6.1 ... Variables ... 145

6.2 ... Constants ... 152

6.3 ... Strings ... 160

6.4 ... Booleans ... 161

6.5 ... Regular Expressions ... 164

6.6 ... REDUCE ... 166

6.7 ... Summary ... 168

7 ... Internal Tables ... 171

7.1 ... Using the Right Table Category ... 171

7.2 ... Avoiding DEFAULT KEY ... 173

7.3 ... INSERT INTO TABLE and APPEND TO ... 174

7.4 ... Verifying the Existence of a Row ... 176

7.5 ... Retrieving Table Contents ... 177

7.6 ... LOOP AT WHERE and Nested IF ... 179

7.7 ... Identifying Unnecessary Table Reads ... 180

7.8 ... Block Processing of Table Rows and Single Row Operations ... 181

7.9 ... DESCRIBE TABLE and Table Function LINES ... 182

7.10 ... Summary ... 183

8 ... Control Flow ... 185

8.1 ... IFs ... 185

8.2 ... Nesting Depth ... 190

8.3 ... Conditions ... 190

8.4 ... CASE ... 196

8.5 ... Do 1 Times ... 200

8.6 ... Summary ... 203

9 ... Comments ... 205

9.1 ... Express Yourself in Code ... 205

9.2 ... Comment Placement and Usage ... 207

9.3 ... Comments to Avoid ... 208

9.4 ... FIXME, TODO, and XXX Comments ... 211

9.5 ... Special Comments: ABAP Doc, Pragmas, and Pseudo Comments ... 212

9.6 ... Summary ... 214

10 ... Formatting ... 215

10.1 ... Consistency in Coding Style ... 216

10.2 ... Optimizing for Reading ... 216

10.3 ... The Pretty Printer ... 217

10.4 ... Number of Statements Per Line ... 218

10.5 ... Line Length ... 219

10.6 ... Condensing the Code ... 220

10.7 ... Blank Lines ... 220

10.8 ... Alignment of Assignment Statements ... 221

10.9 ... Alignment of Variable Declarations ... 222

10.10 ... Placement of Closing Brackets ... 223

10.11 ... Formatting Method Parameters ... 223

10.12 ... Summary ... 227

11 ... Error Handling ... 229

11.1 ... Messages ... 229

11.2 ... Return Codes ... 232

11.3 ... Exceptions ... 236

11.4 ... Raising and Catching ... 245

11.5 ... Summary ... 252

12 ... Unit Testing ... 253

12.1 ... Test Classes ... 254

12.2 ... Test Methods ... 262

12.3 ... Class under Test ... 266

12.4 ... Naming ... 267

12.5 ... Assertions ... 269

12.6 ... Test Doubles ... 279

12.7 ... Test Seams ... 289

12.8 ... Principles ... 291

12.9 ... Summary ... 294

13 ... Packages ... 297

13.1 ... General Package Concepts ... 297

13.2 ... Package Concepts in ABAP ... 299

13.3 ... Package Design Options ... 304

13.4 ... Package Checks ... 308

13.5 ... Consequences of Poor or No Package Strategy ... 316

13.6 ... Summary ... 316

14 ... How to Implement Clean ABAP ... 319

14.1 ... Common Understanding among Team Members ... 319

14.2 ... Collective Code Ownership ... 320

14.3 ... Clean Code Developer Initiative ... 322

14.4 ... Tackling the Broken Window Effect ... 323

14.5 ... Code Review and Learning ... 326

14.6 ... Clean Code Advisor ... 330

14.7 ... Learning Techniques ... 330

14.8 ... Continuous Learning in Cross-Functional Teams ... 334

14.9 ... Summary ... 337

... The Authors ... 339

... Index ... 341

Clean ABAP

A Style Guide for Developers