Design reverse-engineering and automated design-pattern detection in Smalltalk

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LIST OF TABLES...VI LIST OF FIGURES ... VII

1. WHAT ARE DESIGN PATTERNS AND WHY DO WE CARE?... 1

1.1 THE OO DESIGN PROBLEM... 1

1.1.1 Why OO Design is difficult to teach ... 1

1.1.2 Why existing designs are hard to document... 3

1.2 DESIGN PATTERNS... 5

1.2.1 What is a pattern?... 5

1.2.2 Where did patterns come from? ... 5

1.2.3 The pattern form ... 7

1.2.4 An example software design pattern... 8

1.3 HOW PATTERNS ARE USEFUL... 11

1.3.1 Using patterns in developing new designs ... 11

1.3.2 Using patterns to understand existing designs... 12

1.3.3 Documenting frameworks using patterns... 12

1.4 HOW PATTERNS RELATE TO OTHER DESIGN COMPREHENSION WORK... 13

1.4.1 Clichés vs. patterns... 13

1.4.2 Plans vs. patterns... 15

1.4.3 How patterns fit into the design continuum ... 16

1.5 DOCUMENTATION TOOLS FOR PATTERNS... 17

1.6 OUTLINE OF THE REMAINDER OF THE THESIS... 17

2. DETECTING DESIGN PATTERNS ... 19

2.1 INTENT VS. ARTIFACT... 19

2.2 OBJECT-ORIENTED DESIGN INFORMATION IN DESIGN PATTERNS... 19

2.2.1 Class hierarchy representation ... 20

2.2.2 Aggregation/association information ... 20

2.2.3 Message information... 21

2.2.4 Graphically representing design information ... 21

2.3 DETECTING PATTERNS... 23

2.3.1 What makes a pattern detectable?... 23

2.3.2 The GOF patterns ... 24

2.3.3 Composite and Decorator ... 25

2.3.4 Template Method ... 27

2.3.5 Chain of Responsibility... 28

2.3.6 Other potentially detectable patterns ... 31

2.4 SUMMARY... 33

3. DESIGN OF THE REVERSE ENGINEERING TOOL... 34

3.1 STATIC MODELING... 34

3.2 POSSIBLE CHOICES FOR SMALLTALK TYPING... 36

3.3 RUNTIME STATISTICAL TYPING... 37

3.4 DYNAMIC MODELING... 43

3.4.2 Existing Smalltalk message facilities... 43

3.4.3 Dynamic message recording ... 44

3.4.4 Call Tree interpretation ... 44

3.5 PATTERNS INTERPRETATION... 45

3.5.1 Composite/Decorator design... 46

3.5.2 Template Method Design ... 47

3.5.3 Chain of Responsibility design... 48

3.6 ROSE FILE GENERATION... 48

3.7 SUMMARY... 51

4. DEMONSTRATING REVERSE ENGINEERING ... 52

4.1 PROGRAMS UNDER REVIEW... 52

4.2 RESULTS OF ANALYZING THE PROGRAMS... 52

4.3 A NOTE ABOUT CHAIN OF RESPONSIBILITY... 55

4.4 SUMMARY... 56

5. SUMMARY AND CONCLUSIONS... 57

5.1 RESULTS OF THE RESEARCH... 57

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