1.  Copyright 2005 Digital Enterprise Research Institute. All rights reserved. www.deri.org m3pe LIGHT An Extensible Multi-Meta-Model Workflow Execution Environment Simeon Petkov

2. 2 Contents Introduction Problem definition Approach Status Next steps Expectations

3. 3 Workflow SOTA in a nutshell Probably more than 300 products on the market No common model Proprietary models not formally described Not even one accepted common interchange format Practically no interoperability From zur Muehlen, M.: Workflow-based Process Controlling Logos Publishers 2003

4. 4 Problem Definition Elaborate one model / language which is expressive enough to provide a mapping to all present meta-models Use formal foundations for the model to prevent ambiguity and facilitate validation as far as possible Build and execution environment for it Provide mappings to some popular models as an initial proof-of-concept

5. 5 Solution Step 1: Survey on Workflow meta-models Step 2: Evaluation of systems Step 3: Language design Step 4: Execution environment design & implementation Step 5: Mappings to popular models as proof-of-concept examples of expressiveness and extensibility

6. 6 Step 1: Survey Meta-models originating from different domains emphasize on different aspects. Discover the key aspects of Workflow Meta-Models. Analyze these and derive requirements on „Super“-Meta- Model. Analyze dependencies between aspects.

7. 7 Step 2: Analysis Many systems providing workflow functionality provide no access to the underlying model or simply don‘t use one Expressiveness has to be evaluated through the provided user interface Analysis of the most widespread systems using a novel „Top-Up“ approach Set boundaries for the default m3pl expressiveness and m3pe functionality upon results

8. 8 Step 3: Language „Off-the-shelf“ coverage of identified key aspects Extensibility within each aspect without changing the execution environment Possibility of adding further aspects without changing the execution environment

9. 9 Step 4: Reference Implementation m3pl parser Interface framework for aspect- implementations Plug-In based support for language extensions Multi-threaded execution manager Small graphical test-suite

10. 10 Step 5: Mapping Initial approach –Translator from external language to m3pl –Direct mappings of basic constructs Later improvement –Direct creation of the m3pl AST from a foreign model

11. 11 Scope Survey: complete Evaluation: complete Language: basic constructs Execution environment: only support for the present language constructs Mappings: matching constructs from BPEL and one non- XML based language

12. 12 Current Work Language improvements –BNF –Extensibility integration / handling Finishing „light“ system implementation –Web Service Invocation Component –UI –Architectural cosmetics Documentation –Thesis

13. 13 Language: Concepts Extensibility within the aspects –Behavior: user-defined control-flow constructs –Operation: complete –Information: complete –Organization Agent concept for structure Multi-language support for complex constraints (open) –Function Nested workflows Incorporation into the control-flow Synchronization (open) Addition of further aspects –Hooks

14. 14 Language: Examples

15. 15 Concepts (Implementation) Fundamental components: –Workflow: Thread-Extension (informal) –Control Flow: CPN –Data Flow: Built-In support for variables and parameters (informal) –Operations: Extensible hierarchical thread structure (informal) –Organization: Dynamic Beans (UML) and placeholder for third- party query-languages Critical design-issues –Strong decoupling vs. need for inter-aspect communication –Extension handling

16. 16 Workflow Manager Extension Handling ParserBuilders Net Builder Operations static dynamic m3pl + Ext. Direct Communication Events & Listeners Reflection API VisitorsWorkers

17. 17 Status Literature Survey –Finished System Evaluation –6 systems installed –Approach pending Language –Initial support for all key-aspects –Extensible Execution environment –„Dirty“ framework –Initial implementation of the foundations Mappings –Basic BPEL constructs

18. 18 Next Steps (LIGHT) System Evaluation –Elaborate complete „real“ scenarios –Evaluate and document –Reflect on survey (maybe extend requirements on m3pl) m3pe LIGHT –Clean framework –Mapping to one more language –Web service support as an operation Thesis –Document system evaluation –Describe and document implementation

19. 19 Next Steps (Complete) System Evaluation –Acquire more systems –Evaluate –Adjust m3pe according to results if necessary m3pe Complete –Behavior Support for all Workflow Patterns –Organization Provide default organizational meta-model Support for multiple constraint languages (SQL / OCL / …) –Operation Integrate more standards (CORBA / JDBC / …) –Mappings More languages –Process Mining Option for non-defined workflow scenarios

20. 20 Summary Target: complex problem m3pe LIGHT –Small demo of the idea –Provides basic functionality –Handy prototype for detecting problems / bottlenecks fast –Modular composition → decoupling of small sub-systems for specific problems m3pe Complete –Solid foundation –Very big potential

21. 21 Go raibh maith agat!