1. Adopting Open Source Development Tools in a Commercial Production Environment – are we locked-in? Tenth International Workshop on Exploring Modeling Methods in Systems Analysis and Design Porto, Portugal :: 13-14 June, 2005 Anna Persson Henrik Gustavsson Brian Lings Björn Lundell Anders Mattsson Ulf Ärlig

2. Context for the Study Combitech Systems AB Advanced development services for technical real-time systems Company founded in 1992 No of employees: 230 Masters degree: 90 % Average working experience: 8 years Owned by Saab AB Business areas: Automotive, Telecom, Space, Defense, Medical equipment,...

3. Current practice Tool users are often locked in to specific tools or tool vendors since the commercial tools use proprietary formats This is a problem since over the lifetime of a project, tools may have disappeared or may have changed so much that an old data file may not be readable The use of open source tools is a flexible option for reducing lock-in

4. The value of open standards Open standards have a wide range of different advantages From the standpoint of interchange, the support for open standards will simplify interchange since tools only need to support a single open format

5. Generation of XMI document for a UML model (from Stevens, 2003)

6. Open Source UML modelling tools used in the study... ArgoUML http://argouml.ti gris.org Fujaba http://www.fujaba. de Umbrello http://uml.source forge.net XMI version1.01.11.2 Storage format Project-specific XMI UML modelsAll except objectClass, state and activity All except object Forward eng. to Java, C++, PHPJavaJava, C++, PHP, SQL,... Reverse eng. from Java C++ PlatformAll (Java based) Linux (with KDE) Active developers Approx. 25Approx. 35Approx. 5 LicenseBSD Open Source GNU Lesser General Public GNU General Public

7. Case Study: Two different models of different complexity levels were evaluated Model A is a larger model which was exported to an XMI file consisting of 175.000 lines of XMI code for an UML class model containing approximately 170 classes. Model B is a smaller model which was exported to an XMI file consisting of 35.000 lines of XMI code for an UML class model containing approximately 60 classes.

8. Screen shoot from Model A in Rhapsody

9. OSS Modelling tool Screen shoot from Model A in ArgoUML

10. Overview of Model Interchange

11. Steps of interchange process 1.Bring up model in Rhapsody 2.Export model 3.Validate XMI documents –Larger model did not validate due to ordering problem, this was repaired manually 4.Import into Open Source Tools –Neither Fujaba nor Umbrello could import models due to version differences. A third tool is needed to convert between 1.0 and 1.2. ArgoUML had problems even though the XMI versions matched and XMI file was validated against XMI DTD 5.Visual Inspection –Since presentation is not exported, model needs to be shuffled around to be inspected visually 6.Export model from Open Source Tools −Only ArgoUML could import, so ArgoUML alone is used in this step. 7.Validate XMI documents –The exported file did not validate and required some changes 8.Import model into Rhapsody 9.Visual Inspection 10.Repeat from 1 –An outer package was added for each repeat

12. Experiences The experience of Combitech Systems is that the tool market is dynamic and that tools disappear and change during lifetime of a project Using more than one tool has several advantages –Protects investment by allowing model to be imported into other tools –Individual tool users are allowed to use different tools for different tasks according to preference –Customers are increasingly knowledgeable about UML and envision a future where parts of model development are carried out at customer sites

13. XMI Interchange process is not perfect Interchange is dependent on a single combination of XMI and UML versions Round-trip export and import needs some hand-tuning of models One very important find is that interchange is dependent of model complexity: a larger model using mainly the same constructs is more difficult to import correctly More work in the area of XMI support is needed in both Open Source tools and commercial tools

14. Future Work Testing more tool combinations –A study involving a larger set of tools has been performed Visualization and cleaning of XMI files –A visualization engine is being worked on which allows an XMI file to be analysed and edited –This will increase understanding of file structure and facilitate import through removal of offending elements Universal translator –A project is underway to create an engine which translates between the various XMI and UML versions and individual idiosyncrasies of different tools