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Slide 1: Model-driven development of SOA with Web services – using QVT technology Master thesis by Berge Stillingen Department of Informatics, University of Oslo 2005 1
Slide 2: Problem domain and scope  SOA – Service Oriented Architecture  Focus is set on Web services  MDA – Model Driven Architecture  Framework for model-driven development  QVT – Query/Views/Transformations  Upcoming standard for model-to-model transformations from OMG  MOF2Text – MOF Model to Text Transformations  Upcoming standard for model-to-text transformations from OMG  Thesis approach: – – Where is QVT today? Is QVT the right answer when developing SOA using MDD? 2
Slide 3: Contents I: Feature analysis: QVT/MOF2Text candidates II: MOSUQ: SOA/QVT/MOF2Text framework – – Concepts Transformation assets for Java Web services III: Case study: Min/Max replenishment system specified using the framework 3
Slide 4: (I) Feature analysis  Evaluating proposals to the QVT and MOF2Text standards and belonging software (proof of concept) – – – – Analyze their features deriving criteria/requirements from the QVT and MOF2Text RFPs (Request For Proposals to standards) Add additional tool-specific requirements for the proofs of concept Give points for each criteria (e.g. 2/5) The 2 alternatives: QVT MOF2Text SINTEF/Softeam MOFScript MOF2Text-partners OptimalJ (TPL) QVT-Merge Group ATL EXMOF OptimalJ Alt. 1: Alt. 2: – Sum up and use the “winning” alternative to specify transformations for a SOA-MDD framework and case study 4
Slide 5: Requirements/Evaluation criteria Model-to-model trans. (QVT)         Declarative transformation definitions/Model querying – Based on OCL Incremental transformations Reuse of existing OMG specifications – OCL, UML, MOF (Meta Object Facility) MOF 2.0 based transformations/models Additional transformation data Traceability – Importing for debugging Graphical and textual notation … 5
Slide 6: Requirements/Evaluation criteria Model-to-text trans. (MOF2Text)      Reuse of existing OMG language specifications MOF 2.0 based mappings/source models Functions for string manipulation Combining model data with clear text Complex text transformation mappings – – Most mappings are one-to-one (isomorphic) More non-trivial mappings may occurs   Multiple models and support for UML extensibility mechanism … 6
Slide 7: Requirements/Evaluation criteria Other requirements. (tool-specific) Note: Applies to the proofs-of-concept in both alternatives and both QVT and MOF2Text.      OMG standards – UML 2.0 and XMI 2.0 support Explicit UML profile support using multiple files Code assistance Debugging facilities Testing well-formedness 7
Slide 8: Feature analysis results   Alternative 1 wins with a 63% score (alt.2 gets a 55% score) – Low scores, especially on model-to-model transformations OptimalJ: Gives Alt 2. a better score. A more “easy to use” tool than ATL/MOFScript Results worst for the tool-specific req. (other req.) – QVT Alt. 1: QVT-Merge Group ATL EXMOF OptimalJ MOF2Text SINTEF/Softeam MOFScript MOF2Text-partners OptimalJ (TPL) 8 Alt. 2:
Slide 9: (II) MOSUQ – SOA QVT Framework  Model-driven development Of Service Oriented Architectures Using QVT – Implies use of the MOF2Text standard as well  Combined QVT and MOF2Text usage – Serve conceptual guidelines for MDD of SOA using the two standards   Specified concretely for Java Web services Transformations assets: – – – QVT Merge relations (graphical) QVT Merge mappings (textual) ATL transformations – COMET’s Service Architecture modeling 9
Slide 10: MOSUQ concepts  Service Architecture Model PIM (MOF) Draw a COMET based Service Architecture Model – Use COMET stereotypes  Models targeted at the Java Web services platform PSM (MOF)   XML/Code (Text) Java code WSDL documents Config. documents Define a PSM domain for a SOA based platform (main platform) Define wanted artifacts at the code level Identify “sub-platforms” for the PSM domain – Defined by UML profiles or MOF metamodels Add transformations between the abstraction layers Use 3 or more abstraction layers  Refine the PSM domain – – 10
Slide 11: MDD Java Web services Service Architecture model  PIM (MOF) 4 sub-platforms identified – – Trans 1 Trans 2 UML Model for Java Web Services WSDL Model PSM (MOF) – – – refined Trans 3 Trans 4 WSDL (using MOF metamodel) JAX-RPC Java Sun/J2EE Details of the three latter reflected in a UML profile XML/Code (Text)   Java code WSDL documents PSM domain refined 4 transformations added 11
Slide 12: Metamodels for the PSMs (1)   UML 2.0 MM With Java Web services UML profile 12
Slide 13: Metamodels for the PSMs (2)  WSDL metamodel 13
Slide 14: MDD Java Web services  Transformation assets: – BSPack2Def(bsp: Package, def:Definitions) bsp:Package def:Definitions binding bind:Binding QVT Merge relations realizing – QVT Merge mappings – ATL code implementing – MOFScript code service svc:Service svci :Interface message inputMsgs:Message portType pt:PortType message outputMsgs:Message { when } bsp.stereoTypeKindOf(’BusinessServiceSpec’ ) and Interface2WSDL(svci, pt, bind, svc, inputMsgs, outputMsgs) 14
Slide 15: Implementing transformations -Working environment Eclipse based IDE: Rational Software Modeler + ATL transformation engine + MOFScript Source metamodel (EMF) Target metamodel (EMF) ATL code XMI Service Model ATL engine MOFScript engine XMI Platform model (UML profile or MOF metamodel based) XMI Code/ text artefacts 15 Source metamodel (EMF) MOFScript code
Slide 16: Case study: Min/Max Replenishment - applying the MOSUQ framework 16
Slide 17: Case study: Min/Max Replenishment - Service Architecture Model (COMET)     Component model Interface Model Information Model PIM Data types 17
Slide 18: Case study: Min/Max Replenishment - Platform models (1)  WS UML model – Trans 1. applied 18
Slide 19: Case study: Min/Max Replenishment - Platform models (2)  WSDL model – – Shown as object diagram Trans. 2 applied 19
Slide 20: Case study: Min/Max Replenishment - Code artefacts  Java Code – Transformation 3 applied     Value object classes Web service interface classes Web service implementation classes Validated with Eclipse’s Java compiler  WSDL (XML) – Transformation 4 applied   Example with Rpc/literal messaging style Validated with a WDSL XML Schema instance 20
Slide 21: Why use MOSUQ?  - especially concerning the generation of Java code and WSDL documents No PSM (traditional) approach: – PIM to text transformation (code generation)     Annotation of PIMs (stereotypes, tagged values) – w/Additional transformation data No intermediate PSMs One transformation per target artefact at the implementation level (code etc.) Only one language to use  MOSUQ (more MDA adherent): – – PIM to PSM transformations PSM to text and/or PSM to PSM transformations   Commit to multiple ways (languages) of specifying transformation assets Ensures correcting structuring of target specifications reflecting code/text at the implementation level – – Given a well-defined metamodel. Less chance of generating text artefacts violating syntax Formalizing the details of identified platforms by using MM  Separation of concerns – 21
Slide 22: Conclusions  - summary of contributions Evaluation of proposals to QVT and MOF2Text with their belonging proofs-of-concept – Feature analysis: 63% score on alt. 1 (QVT Merge/ATL/MOFScript)  Still work to be done, especially on the tool side  MOSUQ – SOA/QVT framework – Transformations assets  Subject to reuse/alterations – – – ATL code (difficult and time-consuming) MOFScript code QVT Merge specifications – Has proven that the QVT and MOF2Text standards can be combined to realize MDD of SOA  An alternative to MDD of SOA 22
Slide 23: Future work  Alternative QVT-tools: – AMW/AMMA (INRIA)    Lets you define correspondence specifications in the form of weaving models between model artefacts Capable of expressing symmetric rules Transformations in different languages can be generated (XSLT, ATL) Consistency-checking capabilities – Model Transformation Framework (MTF)   MOSUQ enhancements – Apply other PSM profiles for SOA impl.:      BPEL/BPMN Configuration files (DD etc) CORBA/IDL XML registries and UDDI dot NET platform 23