Refactoring: Ruby Edition

Cover......Page 1
Contents......Page 8
Foreword......Page 14
Preface......Page 16
Acknowledgments......Page 21
About the Authors......Page 23
Chapter 1: Refactoring, a First Example......Page 24
 The Starting Point......Page 25
 The First Step in Refactoring......Page 29
 Decomposing and Redistributing the Statement Method......Page 30
 Replacing the Conditional Logic on Price Code with Polymorphism......Page 55
 Final Thoughts......Page 73
 Where Did Refactoring Come From?......Page 74
 Defining Refactoring......Page 75
 Why Should You Refactor?......Page 77
 When Should You Refactor?......Page 80
 Why Refactoring Works......Page 83
 Indirection and Refactoring......Page 84
 Problems with Refactoring......Page 86
 Refactoring and Design......Page 90
 It Takes A While to Create Nothing......Page 92
 Refactoring and Performance......Page 93
 Optimizing a Payroll System......Page 94
Chapter 3: Bad Smells in Code......Page 96
 Long Method......Page 97
 Long Parameter List......Page 99
 Divergent Change......Page 100
 Feature Envy......Page 101
 Primitive Obsession......Page 102
 Case Statements......Page 103
 Speculative Generality......Page 104
 Message Chains......Page 105
 Alternative Classes with Different Interfaces......Page 106
 Refused Bequest......Page 107
 Comments......Page 108
 Repetitive Boilerplate......Page 109
 The Value of Self-Testing Code......Page 110
 The Test::Unit Testing Framework......Page 111
 Developer and Quality Assurance Tests......Page 114
 Adding More Tests......Page 115
 Format of the Refactorings......Page 120
 Finding References......Page 122
Chapter 6: Composing Methods......Page 124
 Extract Method......Page 125
 Inline Method......Page 131
 Inline Temp......Page 133
 Replace Temp with Query......Page 134
 Replace Temp with Chain......Page 137
 Introduce Explaining Variable......Page 140
 Split Temporary Variable......Page 144
 Remove Assignments to Parameters......Page 147
 Replace Method with Method Object......Page 150
 Substitute Algorithm......Page 154
 Replace Loop with Collection Closure Method......Page 156
 Extract Surrounding Method......Page 158
 Introduce Class Annotation......Page 162
 Introduce Named Parameter......Page 165
 Remove Named Parameter......Page 170
 Remove Unused Default Parameter......Page 173
 Dynamic Method Definition......Page 175
 Replace Dynamic Receptor with Dynamic Method Definition......Page 181
 Isolate Dynamic Receptor......Page 183
 Move Eval from Runtime to Parse Time......Page 188
 Move Method......Page 190
 Move Field......Page 195
 Extract Class......Page 198
 Inline Class......Page 202
 Hide Delegate......Page 204
 Remove Middle Man......Page 208
Chapter 8: Organizing Data......Page 210
 Self Encapsulate Field......Page 211
 Replace Data Value with Object......Page 214
 Change Value to Reference......Page 217
 Change Reference to Value......Page 221
 Replace Array with Object......Page 224
 Replace Hash with Object......Page 229
 Change Unidirectional Association to Bidirectional......Page 233
 Change Bidirectional Association to Unidirectional......Page 236
 Replace Magic Number with Symbolic Constant......Page 240
 Encapsulate Collection......Page 242
 Replace Record with Data Class......Page 247
 Replace Type Code with Polymorphism......Page 248
 Replace Type Code with Module Extension......Page 255
 Replace Type Code with State/Strategy......Page 262
 Replace Subclass with Fields......Page 274
 Lazily Initialized Attribute......Page 278
 Eagerly Initialized Attribute......Page 280
 Decompose Conditional......Page 284
 Recompose Conditional......Page 287
 Consolidate Conditional Expression......Page 288
 Consolidate Duplicate Conditional Fragments......Page 291
 Remove Control Flag......Page 292
 Replace Nested Conditional with Guard Clauses......Page 297
 Replace Conditional with Polymorphism......Page 302
 Introduce Null Object......Page 307
 Introduce Assertion......Page 315
Chapter 10: Making Method Calls Simpler......Page 320
 Rename Method......Page 321
 Add Parameter......Page 323
 Remove Parameter......Page 325
 Separate Query from Modifier......Page 326
 Parameterize Method......Page 330
 Replace Parameter with Explicit Methods......Page 333
 Preserve Whole Object......Page 336
 Replace Parameter with Method......Page 340
 Introduce Parameter Object......Page 343
 Remove Setting Method......Page 347
 Hide Method......Page 350
 Replace Constructor with Factory Method......Page 351
 Replace Error Code with Exception......Page 355
 Replace Exception with Test......Page 360
 Introduce Gateway......Page 364
 Introduce Expression Builder......Page 369
 Pull Up Method......Page 376
 Push Down Method......Page 379
 Extract Module......Page 380
 Inline Module......Page 385
 Extract Subclass......Page 386
 Introduce Inheritance......Page 391
 Collapse Heirarchy......Page 394
 Form Template Method......Page 395
 Replace Inheritance with Delegation......Page 409
 Replace Delegation with Hierarchy......Page 412
 Replace Abstract Superclass with Module......Page 415
 The Nature of the Game......Page 420
 Four Big Refactorings......Page 421
 Tease Apart Inheritance......Page 422
 Convert Procedural Design to Objects......Page 428
 Separate Domain from Presentation......Page 429
 Extract Hierarchy......Page 435
Chapter 13: Putting It All Together......Page 440
References......Page 444
 A......Page 446
 C......Page 447
 D......Page 451
 E......Page 454
 F......Page 456
 G......Page 457
 I......Page 458
 M......Page 460
 N......Page 464
 O......Page 465
 P......Page 466
 Q......Page 467
 R......Page 468
 S......Page 473
 T......Page 474
 V......Page 476
 W-X-Y-Z......Page 477