1. Christian Wagner Re-Modeling of complex software systems STRESS 2006 (18.-24.05.2006) Dortmund Christian Wagner

2. Structure Structure: Project environment (DNW) Wind Tunnel Software – DeAs Software modeling tool jABC 3 approaches: –Coarse level modeling –Modelling of basic libraries –Workflow modeling Conclusion and future prospects

3. Christian Wagner Transonic Wind Tunnel Göttingen (DNW-TWG)

4. Christian Wagner The existing software system - DeAs

5. Christian Wagner DeAs environment

6. Christian Wagner Application structure

7. Christian Wagner DeAs redesign End of Lifecycle of the existing DeAs system –A new software system has to be developed –More flexibility, extensibility and ease of use for wind tunnel operators and customers is desirable –Experiences from the existing system should be taken into account –A model based approach shall be considered Question: Is jABC a tool to support this development? Approach: As a case study, the existing system should be modelled with jABC

8. Christian Wagner jABC – Java Application Building Center A tool for graphical library based application development Is an evolution of the Application Building Center which is developed since 1993 Developed at the University of Dortmund

9. Christian Wagner 2 points of view when developing software Application experts –Define single components (SIBs) –Create Service Logic Graphs (SLGs) Programming experts –Coding –Software infrastructure (platform, language, …)

10. Christian Wagner jABC – Service Logic Graph (SLG)

11. Christian Wagner Coarse level modeling Application level modeling with Java Application Building Center Rebuild a coarse granular flow from existing code –Inspecting the code –Group important blocks –Tracing the graph should act like the real system Combining original code and graph Problem: the existing system is written in C++ and jABC in Java Solution: Java Native Mechanism

12. Christian Wagner Coarse level modeling

13. Christian Wagner Coarse level modeling /* * main for project Ap_an */ JNIEXPORT jstring JNICALL Java_aero_dnw_prototype_deas_apa n_Ap_1an__1C_1Ap_1anImpl (JNIEnv *env, jobject myclass) { Icon base_frame_image; Benutzer hilfBenutzer;... /* * main for project Ap_an */ int main (int argc, char **argv) { Iconbase_frame_image; Benutzer hilfBenutzer;... Original codeJNI-method call

14. Christian Wagner Modelling of basic libraries A step into the real code Modeling of important parts is not enough, because the granularity is not fine enough to re-model different parts of a system First approach: is to generate Building Blocks for every atomic library function and the to combine this basic parts to applications or components –Using the existing code –Combining existing code and jABC with Java Native Ca. 400 functions, but most of them are not used

15. Christian Wagner Modelling of basic libraries TWGHDG

16. Christian Wagner Workflow modeling Combining the first two approaches –The coarse approach not fine enough –The basic library approach turns out to be too fine Rebuild the code in a Control Flow Graph –group all parts in the code which belongs to the same functionality and domain, like GUI- or Input/Output-functions –Transfer control structures from the original code to the constructed flow graph Outputs: –Detailed overview over the traces in the system –Easy the see the appearance of functions (how often, situation) –By-product: documentation of the system

17. Christian Wagner Workflow modeling

18. Christian Wagner Workflow modeling

19. Christian Wagner Conclusion Coarse level modeling –Coarse granular approach –The level is unsuitable for system re-design Modeling of basic libraries –Bottom-up analysis –Overhead through unused methods Workflow modeling –Combining the first approaches –Generate Workflows from existing code Current work: –Automatic workflow generation from code –In order to avoid errors –In order to ensure completeness Future goal: –Use jABC to extend and modernize different parts of the existing system