1. Reverse Engineering Goal Models from Legacy Code
Yijun Yu1
Yiqiao Wang1
John Mylopoulos1
Sotirios Liaskos1
Alexei Lapouchnian1
Julio Cesar Sampaio do Prado Leite2
RE’05
The 13th International conference on Requirements Engineering

2. The 13th International conference on Requirements Engineering
1. Motivation
In legacy software, the purpose (goals, requirements) of a software system is almost always lost in legacy code
In the new era, open and dynamic systems require high-variability software
So, we need to recover the purpose of the legacy software in order to adapt it for the new context
RE’05
The 13th International conference on Requirements Engineering

3. Put into reengineering perspective Horseshoe Model
abstract
Reverse engineering
Forward engineering
Requirements
Intentions Tradeoffs
GOAL MODEL
GOAL MODEL
customizable architecture
Architectures
SOA
BEHAVIOUR MODEL
Web services
Functions
components
LEGACY CODE
Code ……
time
RE’05
The 13th International conference on Requirements Engineering

4. The 13th International conference on Requirements Engineering
Hard goal model
Here is an example of a hard goal model, which is an AND/OR graph.
RE’05
The 13th International conference on Requirements Engineering

5. The 13th International conference on Requirements Engineering
Soft goal model
Here is an example of a soft goal model, which is an AND/OR graph extended with the partial reasoning rules.
RE’05
The 13th International conference on Requirements Engineering

6. Put into reengineering perspective Horseshoe Model
Reverse engineering
Forward engineering
Requirements
Intentions Tradeoffs
GOAL MODEL
GOAL MODEL
customizable architecture
Architectures
SOA
BEHAVIOUR MODEL
Web services
Functions
components
LEGACY CODE
Code ……
RE’05
The 13th International conference on Requirements Engineering

7. 2. A tool supported reverse engineering
2.1
FPT compiler
FPT compiler
2.2
2.3
2.4
2.4
RE’05
The 13th International conference on Requirements Engineering

8. The 13th International conference on Requirements Engineering
2.1 Software Refactoring
Software refactoring = “Restructuring existing code by altering its internal structure without changing its external behaviour” –- Martin Fowler, also “Comments signal the semantic gap between the code and the programmers’ purpose”
entry
// the following does S
S1(I1, O1);
S2(I2, O2);
// other …
// refactored
S(I, O);
exit
I = Variables defined before the entry of the block
O= Variables defined in the block that will be used after
the exit
RE’05
The 13th International conference on Requirements Engineering

9. 2.2 Statecharts refactoring
Statecharts are used to bridge the semantics abstraction gap between source code and goal models
refactored source code
equivalent statechart
higher-level statechart
unstructured high-level program
structured high-level program
RE’05
The 13th International conference on Requirements Engineering

10. 2.3 Goal model from structured programs
The 13th International conference on Requirements Engineering

11. 2.4 Identifying NFR and softgoals
Create a set of functional tests
If removing a method does not break the functional test, then the goal associated with the method is a NFR
If the identified NFR improves some quality attribute, then
There is a soft goal for the quality attribute
There is a contribution from the NFR to the softgoal
RE’05
The 13th International conference on Requirements Engineering

12. The 13th International conference on Requirements Engineering
3. Case studies
Case study selection criteria
software systems as they are the target for personal RE
Software popularity: with a large user base, must support wide-range of requirements
Open-source: the validity of the findings can be verified
Applicable with our tool support
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The 13th International conference on Requirements Engineering

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3.1 The Columba case study
Why Columba?
it is an system
popular
140 KLoc
Open-source
Java
Ver. 1.0RC2
What’s New!
Ver. 1.0RC3 has put one of our resulting NFR into comments
1 ColumbaLogger.createDefaultHandler();
2 registerCommandLineArguments();
3 // handle commandline parameters
4 if (handleCoreCommandLineParameters(args))
5 System.exit(0);
...
1 ColumbaLogger.createDefaultHandler();
2 registerCommandLineArguments();
3 handle_commandline_parameters(args); ...
1 // ColumbaLogger.createDefaultHandler();
2 registerCommandLineArguments();
3 handle_commandline_parameters(args);
...
boolean maintainability_logging = false;
...
1 if (maintainability_logging)
2 ColumbaLogger.createDefaultHandler();
3 registerCommandLineArguments();
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The 13th International conference on Requirements Engineering

14. The 13th International conference on Requirements Engineering

15. The 13th International conference on Requirements Engineering
A running Columba
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The 13th International conference on Requirements Engineering

16. The core functional Columba
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17. JUnit testing for Preserved Functionality
The 13th International conference on Requirements Engineering

18. 3.2 The Squirrel Mail case study
Why Squirrel Mail?
it is also an system
popular
PHP + HTML
70 KLoc
Open-source
unstructured
Check this:
It’s reliable, secure, easy to use
but not that fast …
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The 13th International conference on Requirements Engineering

19. The 13th International conference on Requirements Engineering
Restructure AST Goal Graph into Stakeholder Goals
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The 13th International conference on Requirements Engineering

20. The 13th International conference on Requirements Engineering
4. Conclusion
A reverse engineering process is proposed to recover a goal model from legacy code.
This is a critical step in reengineering legacy code to improve its quality through variability.
Reverse Engineering research has focused almost exclusively on recovering design information (rather than purposes)
Future work
Need to further evaluate the effectiveness of heuristics used
Need more experiments
RE’05
The 13th International conference on Requirements Engineering

21. Welcome to the 1st RETR workshop
Reverse engineering to Requirements
Collocated with WCRE’05, November Pittsburg, USA
RETR
'05
RE’05
The 13th International conference on Requirements Engineering