Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications
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The document outlines a proposed approach for reverse engineering VBA-based Excel spreadsheet applications to enhance comprehension and maintenance. It discusses the widespread use of spreadsheets across various domains, the challenges posed by their complexity, and introduces a heuristic-based method for reconstructing data models and understanding user interfaces. The authors also present a tool called 'Exact' designed to extract and visualize the structure and dependencies of spreadsheet applications.
Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications
- 1. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Department of Electrical Engineering and Information Technologies University of Naples “Federico II”, Italy Domenico Amalfitano Nicola Amatucci Vincenzo De Simone Anna Rita Fasolino Porfirio Tramontana 2nd Workshop on Software Engineering Methods in Spreadsheets Florence, Italy 18th May, 2015
- 2. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Context and Motivations Context ◦ Reverse Engineering of Excel Spreadsheet Applications Motivation ◦ Propose techniques and tools to support the comprehension of VBA based Spreadsheet applications 2 of 19SEMS 15 – Florence, Italy – May 18th
- 3. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Why reverse engineering spreadsheet applications? Spreadsheets are widely adopted ◦ for different purposes: calculation, storage, collaboration, etc. ◦ in different domains: business, automotive, engineering, science, medical, etc. Need for their comprehension in different scenarios ◦ individual comprehension ◦ knowledge transferring ◦ re-documentation ◦ Maintenance and evolution ◦ migration towards different architectures 3 of 19SEMS 15 – Florence, Italy – May 18th
- 4. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Excel Spreadsheet Applications Comprehension Issues Poor or absent internal and external documentation No clear distinction between different layers ◦ Data, Business Logic, Presentation Spreadsheet application can be complex ◦ Data spread on different sheets ◦ Data dependencies through formulas ◦ Use of VBA code Enhanced user interface (User Forms, shapes, controls) User defined functionalities (Macros) and functions Handling of events related to default or user defined elements Direct and indirect dependencies through VBA code 4 of 19SEMS 15 – Florence, Italy – May 18th
- 5. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Proposed Reverse Engineering Approach Data Model Reverse Engineering ◦ performed to reconstruct a conceptual model of the data stored in the spreadsheet application. User Interface and Business Logic Reverse Engineering ◦ performed to comprehend both the structure and the behavior of User Interface (UI) and the functionalities provided by the application. 5 of 19SEMS 15 – Florence, Italy – May 18th
- 6. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Data Model Reverse Engineering We propose an heuristic-based approach ◦ Based on our experience in an industrial domain1,2,3 ◦ process made of seven sequential steps to infer, with gradual refinements, an UML class diagram of the considered spreadsheet application ◦ in each step, one or more heuristic rules are executed. Heuristic rules ◦ adapted from rules defined in the literature or ◦ defined by us exploiting some formatting properties typical of spreadsheet applications and analyzing the cells content 1. Amalfitano, D.; Fasolino, A.R.; Maggio, V.; Tramontana, P.; Di Mare, G.; Ferrara, F.; Scala, S., “Migrating legacy spreadsheets-based systems to Web MVC architecture: An industrial case study” - CSMR-WCRE 2014 2. Amalfitano, D.; Fasolino, A.R.; Maggio, V.; Tramontana, P.; De Simone V., “Reverse Engineering of Data Models from Legacy Spreadsheets-Based Systems: An Industrial Case Study” - SEBD 2014 3. Amalfitano, D.; Fasolino, A.R.;Tramontana, P.; De Simone V.; Di Mare, G.; Scala, S., “Information Extraction from Legacy Spreadsheet-based Information System - An Experience in the Automotive Context” - DATA 2014 6 of 19SEMS 15 – Florence, Italy – May 18th
- 7. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Application of heuristics - Examples 7 of 19SEMS 15 – Florence, Italy – May 18th For example, applying one of the rule to the worksheet Sheet1, two separate areas are identified. In this case we introduce a class for each areas and a composition relation between these classes and the one related to the sheet. Sheet1 is composed by Sheet1_Area1 and Sheet1_Area2
- 8. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Application of heuristics - Examples 8 of 19SEMS 15 – Florence, Italy – May 18th In this other example, we applied another rule that exploits the identification of merged cells to extract different classes from an area under analysis. As the figure shows we were able to identify from the Area1 in Sheet1 2 different classes and an association between them
- 9. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Business Logic Reverse Engineering definition of a model that takes into account the main elements of VBA-based spreadsheet applications and their relationships Introduction of different views of these applications on the basis of the model we presented development of a tool to support the comprehension of these kind of applications providing extraction and visualization features 9 of 19SEMS 15 – Florence, Italy – May 18th
- 10. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Modeling VBA based Spreadsheet Applications - 1 10 of 19SEMS 15 – Florence, Italy – May 18th We provided different views of a spreadsheet application: we reported the main elements composing the application and their composition and generalization relationship. In the left side are reported the graphical elements of a spreadsheet application whereas in the right one the code elements.
- 11. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Modeling VBA based Spreadsheet Applications - 2 11 of 19SEMS 15 – Florence, Italy – May 18th In this other view we reported the main dependencies between the elements composing these applications. In particular we considered • call dependencies between procedures • write/read dependencies between procedures and cells • open/hide and unload dependencies between procedures and user form Besides we also reported what procedure handles events of given elements.
- 12. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications EXACT – EXcel Application Comprehension Tool Extraction of data from the spreadsheet application Abstraction of the extracted data according to the proposed model Generation of different views 12 of 19SEMS 15 – Florence, Italy – May 18th
- 13. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications EXACT – EXcel Application Comprehension Tool – provided views Structural Views ◦ Elements composing the application and their relationships ◦ Details related of an element by clicking on it User Functionalities Views ◦ List all the user defined functionalities present Cell Dependencies Views ◦ List of potential dependencies between cells through formulas, validation rules and VBA code Report & Metrics Views ◦ Metrics about the complexity of the application (worksheets, shapes, userforms, modules, procedures, LOCs) 13 of 19SEMS 15 – Florence, Italy – May 18th
- 14. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Visualization features provided by EXACT - 1 14 of 19SEMS 15 – Florence, Italy – May 18th In this view, the main structure of the application is shown.
- 15. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Visualization features provided by EXACT - 2 15 of 19SEMS 15 – Florence, Italy – May 18th By clicking on an element, further details on the element … ... and a view showing its dependencies are reported
- 16. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Visualization features provided by EXACT – User Functionalities Views 16 of 19SEMS 15 – Florence, Italy – May 18th This view shows all the events defined on an element (Workbook, Active Worksheet and UserForms). In this example all the events related to the selected User Form are reported
- 17. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Visualization features provided by EXACT – User Functionalities Views 17 of 19SEMS 15 – Florence, Italy – May 18th By clicking on an event (in this case UserForm_Initialize ) a new view appears showing the potential dependencies of the event handler.
- 18. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Future Works Evaluation of the tool in real business and industrial contexts to support professionals in executing comprehension tasks of VBA spreadsheet applications Extending the model taking into account other Excel features Improving the features and the views provided by EXACT 18 of 19SEMS 15 – Florence, Italy – May 18th
- 19. Toward Reverse Engineering of VBA Based Excel Spreadsheets Applications Thanks for your attention 19 of 19SEMS 15 – Florence, Italy – May 18th Questions ? Further Information: http://reverse.dieti.unina.it @REvERSE_UNINA vincenzo.desimone2@unina.it