RED Project
RED stands for reverse engineering of UML sequence diagrams. The goal of this project is to develop
state-of-the-art algorithms for extracting sequence diagrams from Java
code.
Reverse-Engineered UML Sequence Diagrams
Sequence diagrams play a central role in
UML modeling of object interactions. Reverse engineering of sequence
diagram allows the automatic extraction of such diagrams from existing
code. This is often necessary during iterative development. A
typical scenario is to perform design recovery through reverse
engineering of class diagrams and sequence diagrams in the beginning
of the current iteration, based on the last iteration's code.
Additional reverse engineering is also usually necessary
during an iteration.
Software maintenance can also benefit from
reverse-engineered sequence diagrams. These diagrams are particularly
well-suited for representing interactions in object-oriented
software.
Automatic design recovery of object interactions for
software understanding and maintenance requires
effective reverse engineering of sequence diagrams.
Object interactions are an essential consideration for testing
of object-oriented software. Various testing approaches consider
the interactions represented by sequence diagrams
as part of their coverage requirements. These
coverage goals can be defined with respect to different elements of
statically-constructed sequence diagrams which are extracted from the
code under test. Subsequent run-time analysis during test execution
can be used to determine the coverage of these diagram elements and to
highlight potential test weaknesses.
Static Analyses for Reverse-Engineered Sequence Diagrams
The work on RED revealed various challenging research problems.
The difficulty of these problems becomes clear
when one considers commercial tools that perform reverse engineering
of UML sequence diagrams from Java code. UML modeling tools
can produce
reverse-engineered diagrams that are incorrect or incomplete. These
are not low-quality tools — in fact, they are mature,
well-designed, high-quality commercial tools that are very useful
during software development. However, the conceptual problems related
to correct reverse engineering are complicated
and require advanced static analysis techniques. We have solved several
of these problems with
state-of-the-art static analyses for reverse engineering of UML sequence diagrams.
The following challenges were addressed:
- Given some call site in the analyzed code, how should the
receiver object(s) at this site be represented in the diagram? Our
efforts to answer this question produced a novel object naming
analysis [ICSE05].
- How should the intraprocedural flow of control in the code be
represented in the reverse-engineered sequence diagrams? To
answer this question, we defined a new control-flow analysis
for mapping a method's control-flow graph to UML 2.0 interaction
fragments
[PASTE05].
This work systematically revealed the
limited expressive power of UML control-flow primitives, and the
tradeoffs that tool builders need to face when handling the
intraprocedural flow of control.
- How should infeasible call chains be eliminated from the
diagrams? Our work on call chain analysis showed that
infeasible chains in the call graph occur even when using precise call
graph construction algorithms
[ISSTA04, PASTE04].
Testing Based on Reverse-Engineered Sequence Diagrams
Based on the reverse-engineered diagrams, we defined several
control-flow coverage criteria for testing the interactions among a
set of collaborating objects. The sequences of messages in the
diagrams were used to define the coverage goals for the family of
criteria, by generalizing traditional techniques
such as
branch coverage and path coverage. We also defined a run-time
analysis that gathers coverage measurements for the criteria. A novel
approach (based on integer linear programming) was used to estimate
the complexity of each criterion.
The
results of this work compared different approaches for testing of
object interactions and provided new insights for testers and for
builders of test coverage tools
[FASE05].
Visualization of Reverse-Engineered Sequence Diagrams
Effective visualization of large-scale complex
reverse-engineered sequence diagrams is challending.
Due to their
large size and inefficient spatial design, the diagrams could easily
become useless to software engineers. We investigated the visual
limitations of UML sequence diagrams and developed a set of techniques
for overcoming these limitations
[VISSOFT05].
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