1. Authors: Khaled Abdelsalam Mohamed Amr Kamel
Reverse Engineering State and Strategy Design Patterns using Static Code Analysis
Authors:
Khaled Abdelsalam Mohamed
Amr Kamel

2. Software Development Continuous changes Bug fixing New features
Requirements/Technological

3. Software Development Development team can also change
New team members may need to learn from scratch
Hard to know every implementation detail

4. Software Development Development team can also change
New team members may need to learn from scratch
Documentation becomes vital
Tedious to keep updated

5. Software Development
There have been many techniques to ease legacy code insight and understanding

6. Legacy/Undocumented code
Design patterns have specific intentions
Leads to understanding the usage of different parts of the software

7. Legacy/Undocumented code
How can we extract design patterns from software?
Decorator
Strategy
Observer
State

8. The techniques Analysis type Search Methodology
How to map the software properties
Search Methodology
How to search those properties

9. The techniques Analysis type:
Structural analysis: Recovers Class relationships, method signatures, compositions etc.
Proxy, Decorator, Adapter etc.

10. The techniques Analysis type:
Structural analysis: Recovers Class relationships, method signatures, compositions etc.
Proxy, Decorator, Adapter etc.
Behavioral analysis: Recovers the components actions of the software.
Iterator, State, Observer etc.

11. The techniques Analysis type:
Structural analysis: Recovers Class relationships, method signatures, compositions etc.
Proxy, Decorator, Adapter etc.
Behavioral analysis: Recovers the components actions of the software.
Iterator, State, Observer etc.
Semantic analysis: Supplements both. Uses naming conventions.

12. The techniques Search Methodology:
Database queries: Code is mapped with metadata structures

13. The techniques Search Methodology:
Database queries: Code is mapped with metadata structures
Constraint Resolver: Code Is mapped with addition of constraints and roles

14. The techniques Search Methodology:
Database queries: Code is mapped with metadata structures
Constraint Resolver: Code Is mapped with addition of constraints and roles
XPG formalism and parsing: Source code mapped as a visual language

15. The techniques Search Methodology:
Database queries: Code is mapped with metadata structures
Constraint Resolver: Code Is mapped with addition of constraints and roles
XPG formalism and parsing: Source code mapped as a visual language
Code UML structures used to derive metrics. Found metrics compared against the expected metrics of a given Design Pattern

16. The techniques Static Analysis Dynamic Analysis
Process to analyze code by deriving information from the source code
Dynamic Analysis
Derive information from running software
Static Analysis -> Can be done in incomplete code

17. The techniques Static Analysis
Process to analyze code by deriving information from the source code

18. The techniques Static Analysis Dynamic Analysis
Process to analyze code by deriving information from the source code
Dynamic Analysis
Derive information from running software

19. The techniques Static Analysis Dynamic Analysis
Process to analyze code by deriving information from the source code
Dynamic Analysis
Derive information from running software
Static Analysis -> Can be done in incomplete code

20. The approach Use Static code analysis to find design patterns
Program dependency
Control dependency
Data dependency

21. The approach The code is mapped as a graph
Design patterns graphs are matched to code generated graph

22. The approach
The Joern Platform was modified to also save class hierarchy
Graph data persisted with Neo4j
Gremlin to query the data
Joern

23. The approach - Steps
1. Load source code

24. The approach - Steps
1. Load source code
2. Code property graph
Joern

25. The approach - Steps Joern 1. Load source code 2. Code property graph
3. Save graph in Neo4j DB
Joern

26. 4. Add Design Patterns Attributes
The approach - Steps
1. Load source code
2. Code property graph
3. Save graph in Neo4j DB
4. Add Design Patterns Attributes
Joern

27. 4. Add Design Patterns Attributes
The approach - Steps
1. Load source code
2. Code property graph
3. Save graph in Neo4j DB
4. Add Design Patterns Attributes
5. Select Design Pattern
Joern

28. The approach - Steps Joern 1. Load source code 2. Code property graph
3. Save graph in Neo4j DB
4. Add Design Patterns Attributes
5. Select Design Pattern
6. Load Design Pattern Matching Queries
Joern

29. The approach - Steps Joern 1. Load source code 2. Code property graph
3. Save graph in Neo4j DB
4. Add Design Patterns Attributes
5. Select Design Pattern
6. Load Design Pattern Matching Queries
7. Run Queries
Joern

30. The approach - Steps Joern 1. Load source code 2. Code property graph
3. Save graph in Neo4j DB
4. Add Design Patterns Attributes
5. Select Design Pattern
6. Load Design Pattern Matching Queries
7. Run Queries
8. Display Graph Matching Patterns results
Joern

31. The approach State and Strategy design patterns issue
Similar structure
Different behavior

32. State and Strategy design patterns issue
Similar structure
Different behavior vs

33. State and Strategy design patterns issue

34. Metadata graph enrichment
Methods to Classes
Link between classes and their methods (Joern misses)

35. Metadata graph enrichment
Methods to Classes
Link between classes and their methods (Joern misses)
Inheritance
Adds the relation between Super class and their subclasses

36. Metadata graph enrichment
Methods to Classes
Link between classes and their methods (Joern misses)
Inheritance
Adds the relation between Super class and their subclasses
Abstract (Virtual) Methods
With body
No body

37. Metadata graph enrichment
Class Aggregates Class

38. Metadata graph enrichment
Class Aggregates Class
Link between classes aggregating other classes
Method Creates Class
Link between a method and the class of the object it instantiates

39. Metadata graph enrichment
Class Aggregates Class
Link between classes aggregating other classes
Method Creates Class
Link between a method and the class of the object it instantiates
Method Overrides Method
Link between methods overriding each other

40. Metadata graph enrichment
Class Aggregates Class
Link between classes aggregating other classes
Method Creates Class
Link between a method and the class of the object it instantiates
Method Overrides Method
Link between methods overriding each other
Method Calls Method
Link between a caller method and the method called

41. Solving the State and Strategy issue
Step 1
Find State and Strategy candidates
Step 2
Differentiate State and Strategy candidates

42. Differentiating State and Strategy candidates
Loop each pattern candidate
Find class aggregations variables (let’s call it X)
Use find methods M that use variables X
Check if methods M includes subclasses from pattern candidates
If c is truth then the candidate is a State design
Check if methods from c includes client method from pattern candidates
If f is true then the candidate is a strategy

43. Authors Conclusion
Successfully use Code Property Graph to map Design patterns
Able to differentiate Strategy and State
Uses only static analysis
As future work
Make catalogue of all relationships and properties of design patterns
Support multiple graph pattern variants

44. Paper critique Abstract and Introduction
Deviated from the described a Approach
Focus in the Strategy/State
No mention of qualitative/quantitative study

45. My Conclusion Needs to evaluate the approach Practical idea Constrain
Test on well know good code (e.g, Linux Kernel on Github)
Practical idea
Constrain
Needs well written code that uses design pattern

46. References https://refactoring.guru/design-patterns/strategy
Kniesel, Gunter and Binun, Alexander, "Standing on the shoulders of giants- a data fusion approach to design pattern detection," in Program Comprehension, ICPC'09. IEEE 17th International Conference on,
T. A. Ghaleb, "The role of open source software in program analysis for reverse engineering," 2016 2nd International Conference on Open Source Software Computing (OSSCOM), Beirut, 2016, pp doi: /OSSCOM
G. Costagliola and G. Polese, "Extended positional grammars," Proceeding IEEE International Symposium on Visual Languages, Seattle, WA, 2000, pp doi: /VL