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Michele Chinosi University of Insubria – Varese (Italy) BPeX: A New Approach to BPMN Model Portability. Agenda. Brief introduction to BPMN, WS-BPEL, XPDL BPeX: a new modeling approach A view of XPDL “weaknesses” How BPeX can aid to overcome these weak points
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Michele Chinosi University of Insubria – Varese (Italy) BPeX: A New Approach to BPMN Model Portability
Agenda Michele Chinosi - Architecture & Process - 2008 Brief introduction to BPMN, WS-BPEL, XPDL BPeX: a new modeling approach A view of XPDL “weaknesses” How BPeX can aid to overcome these weak points A comparison between XPDL and BPeX
A BriefIntroduction Michele Chinosi - Architecture & Process - 2008 BPMN (Business Process Modeling Notation), developed by BPMI and adopted as standard by OMG (2006, BPMN 1.0 – 2008, BPMN 1.1) WS-BPEL (Web Services – Business Process Execution Language), developed by BEA, IBM & Microsoft, adopted by OASIS as standard. Version 2.0 (2007). XPDL (XML Process Definition Language), developed by WfMC. (2005, XPDL 2.0 – 2008, XPDL 2.1).
A Brief Introduction Michele Chinosi - Architecture & Process - 2008 • BPMN is a graphical notation to model (represent) business processes. • Standard for the look of a process • WS-BPEL is an “execution language” • definition of web services orchestration • independent from BPMN • XPDL stores and exchanges the process diagrams • process design format • extended to support BPMN
BPeX: Business Process eXtensions The BPMN-XPDL-BPEL value chain From Keith Swenson blog “Go Flow”, posted May 26, 2006 Michele Chinosi - Architecture & Process - 2008 5
BPeX: Business Process eXtensions Michele Chinosi - Architecture & Process - 2008 6
A Comparison BetweenWS-BPEL and XPDL Michele Chinosi - Architecture & Process - 2008
Some XPDL Weaknesses in Details Michele Chinosi - Architecture & Process - 2008 Elements renaming Complex conceptual model Lack of a native referential integrity Complex queries
Elements Renaming XPDL 2.0: comes 1 year before OMG published BPMN specification supports all the elements provided by BPMN specification maintains the possibility to describe more generic workflow diagrams avoid redundancy and duplicates Michele Chinosi - Architecture & Process - 2008
A Complex Conceptual Model Michele Chinosi - Architecture & Process - 2008 We analyzed the XML serialization provided with the example inside the XPDL specification We depicted a more high-level graphical conceptual model of the XML tree We compared the model with the Business Process Diagram
An Example Process This process is taken from XPDL specification [Document nr. WFMC-TC-1025, Section 8.1, pp. 109-127] and modeled using BPMN Michele Chinosi - Architecture & Process - 2008
Michele Chinosi - Architecture & Process - 2008 A Complex Conceptual Model
A Complex Conceptual Model Michele Chinosi - Architecture & Process - 2008 • XPDL was not originally developed to represent natively BPMN diagrams • XPDL has to maintain a backward compatibility with its previous version • Old names, old structure, old relationships This introduces: • more complexity • some misunderstandings • fragmentation of information
A Complex Conceptual Model Michele Chinosi - Architecture & Process - 2008
Lack of Native Referential Integrity Constraints Michele Chinosi - Architecture & Process - 2008 All the elements do not have a unique ID ID and IDRef are of type xsd:NMTOKEN More than one element have the same ID BPMN specification requires the ID field to be “a unique Id that identifies the object from other objects within the Diagram”
Lack of Native Referential Integrity Constraints Michele Chinosi - Architecture & Process - 2008
Lack of Native Referential Integrity Constraints Michele Chinosi - Architecture & Process - 2008 IDREFs are of type xsd:NMTOKEN It is possible to set as IDREF value a non-existent ID There is the need of a software tool to check the correctness of the values XPDL specification states that “The Process attribute defines the Process that is contained within the Pool”
Lack of Native Referential Integrity Constraints Michele Chinosi - Architecture & Process - 2008
BPeX: Business Process eXtensions Michele Chinosi - Architecture & Process - 2008 • ID and IDREF are defined as of types xsd:ID and xsd:IDREF • We add xsd:KEY and xsd:KEYREF to enforce constraints • We can assure that a Start Event of type Message will have all and only the attributes provided by BPMN specification • We can statically validate the model without using software tools
Complex Queries With XPDL for $x in (//Activity[@Id=10]), $y in (//Pool[@Process = //$x/ancestor::WorkflowProcess[1]/@Id]//Lane/@Name) return $y Result: /Package[1]/Pools[1]/Pool[2]/Lanes[1]/Lane[1]/@Name - Lane-0 With BPeX Michele Chinosi - Architecture & Process - 2008 Which Lane does the Task with Id=10 belong to? //Lane[//Task/@Id=10]/@Name Result: /BPD[1]/Pool[2]/Lane[1]/@Name – Lane-0
BPeX: Business Process eXtensions Michele Chinosi - Architecture & Process - 2008 • Built from scratch with a clear conceptual model • Not based on WS-BPEL or XPDL • BPeX can be translated to XPDL and BPEL using XSLT • BPeX can be extended to integrate XPDL or BPEL features • It supports all BPMN elements and features • It has an XML-Schema serialization • It strengthens BPMN weak connections • Static analysis and validation • Constraints / Metrics / Extensions
BPeX: success stories Michele Chinosi - Architecture & Process - 2008 Partnership with Euranet (an European business consulting company) and Università degliStudidi Bologna (Italy) We modeled some real cases taken from several SMEs We started implementing some constraints taken from NIST / ISO procedures to aid users modeling processes We extended BPeX to support some simple time/cost metrics (BPM 2007) We successfully added privacy policies to web-based processes modeled with BPMN (WOSIS 2008)
BPeX Conceptual Model Graphical BPMN model Graphical BPeX model Michele Chinosi - Architecture & Process - 2008
Example Process in BPeX Michele Chinosi - Architecture & Process - 2008
XPDL and BPeX comparison Michele Chinosi - Architecture & Process - 2008 BPeX XPDL
Conclusions Michele Chinosi - Architecture & Process - 2008
Summary Michele Chinosi - Architecture & Process - 2008 • Introduction to BPMN, BPEL, XPDL • Our proposal BPeX • Analysis of the XPDL weak points using a practical example • How BPeX can aid to overcome these weak points • A comparison between XPDL and BPeX
Questions? michele.chinosi@uninsubria.it http://bpex.sourceforge.net Michele Chinosi - Architecture & Process - 2008 VARESE