重构：改善既有代码的设计（英文版）

Chapter 1: Refactoring, a First Example 1

　The Starting Point　1

　The First Step in Refactoring　7

　Decomposing and Redistributing the Statement Method　8

　Replacing the Conditional Logic on Price Code with Polymorphism　34

　Final Thoughts　52

Chapter 2: Principles in Refactoring　53

　Defining Refactoring　53

　Why Should You Refactor　55

　When Should You Refactor　57

　What Do I Tell My Manager　60

　Problems with Refactoring　62

　Refactoring and Design　66

　Refactoring and Performance　69

　Where Did Refactoring Come From　71

Chapter 3: Bad Smells in Code (by Kent Beck and Martin Fowler)　75

　Duplicated Code　76

　Long Method　76

　Large Class　78

　Long Parameter List　78

　Divergent Change　79

　Shotgun Surgery　80

　Feature Envy　80

　Data Clumps　81

　Primitive Obsession　81

　Switch Statements　82

　Parallel Inheritance Hierarchies　83

　Lazy Class　83

　Speculative Generality　83

　Temporary Field　84

　Message Chains　84

　Middle Man　85

　Inappropriate Intimacy　85

　Alternative Classes with Different Interfaces　85

　Incomplete Library Class　86

　Data Class　86

　Refused Bequest　87

　Comments　87

Chapter 4: Building Tests　89

　The Value of Self-testing Code　89

　The JUnit Testing Framework　91

　Adding More Tests　97

Chapter 5: Toward a Catalog of Refactorings　103

　Format of the Refactorings　103

　Finding References　105

　How Mature Are These Refactorings　106

Chapter 6: Composing Methods　109

　Extract Method　110

　Inline Method　117

　Inline Temp　119

　Replace Temp with Query　120

　Introduce Explaining Variable　124

　Split Temporary Variable　128

　Remove Assignments to Parameters　131

　Replace Method with Method Object　135

　Substitute Algorithm　139

Chapter 7: Moving Features Between Objects　141

　Move Method　142

　Move Field　146

　Extract Class　149

　Inline Class　154

　Hide Delegate　157

　Remove Middle Man　160

　Introduce Foreign Method　162

　Introduce Local Extension　164

Chapter 8: Organizing Data　169

　Self Encapsulate Field　171

　Replace Data Value with Object　175

　Change Value to Reference　179

　Change Reference to Value　183

　Replace Array with Object　186

　Duplicate Observed Data　189

　Change Unidirectional Association to Bidirectional　197

　Change Bidirectional Association to Unidirectional　200

　Replace Magic Number with Symbolic Constant　204

　Encapsulate Field　206

　Encapsulate Collection　208

　Replace Record with Data Class　217

　Replace Type Code with Class　218

　Replace Type Code with Subclasses　223

　Replace Type Code with State/Strategy　227

　Replace Subclass with Fields　232

Chapter 9: Simplifying Conditional Expressions　237

　Decompose Conditional　238

　Consolidate Conditional Expression　240

　Consolidate Duplicate Conditional Fragments　243

　Remove Control Flag　245

　Replace Nested Conditional with Guard Clauses　250

　Replace Conditional with Polymorphism　255

　Introduce Null Object　260

　Introduce Assertion　267

Chapter 10: Making Method Calls Simpler　271

　Rename Method　273

　Add Parameter　275

　Remove Parameter　277

　Separate Query from Modifier　279

　Parameterize Method　283

　Replace Parameter with Explicit Methods　285

　Preserve Whole Object　288

　Replace Parameter with Method　292

　Introduce Parameter Object　295

　Remove Setting Method　300

　Hide Method　303

　Replace Constructor with Factory Method　304

　Encapsulate Downcast　308

　Replace Error Code with Exception　310

　Replace Exception with Test　315

Chapter 11: Dealing with Generalization　319

　Pull Up Field　320

　Pull Up Method　322

　Pull Up Constructor Body　325

　Push Down Method　328

　Push Down Field　329

　Extract Subclass　330

　Extract Superclass　336

　Extract Interface　341

　Collapse Hierarchy　344

　Form Template Method　345

　Replace Inheritance with Delegation　352

　Replace Delegation with Inheritance　355

Chapter 12: Big Refactorings (by Kent Beck and Martin Fowler)　359

　Tease Apart Inheritance　362

　Convert Procedural Design to Objects　368

　Separate Domain from Presentation　370

　Extract Hierarchy　375

Chapter 13: Refactoring, Reuse, and Reality (by William Opdyke)　379

　A Reality Check　380

　Why Are Developers Reluctant to Refactor Their Programs　381

　A Reality Check (Revisited)　394

　Resources and References for Refactoring　394

　Implications Regarding Software Reuse and Technology Transfer　395

　A Final Note　397

　References　397

Chapter 14: Refactoring Tools (by Don Roberts and John Brant)　401

　Refactoring with a Tool　401

　Technical Criteria for a Refactoring Tool　403

　Practical Criteria for a Refactoring Tool　405

　Wrap Up　407

Chapter 15: Putting It All Together (by Kent Beck)　409

References　413

List of Soundbites　417

Index　419