BPEL and XPDL

Park, Nam JoonISILab

Introduction

• Feedback based framework for semi-automatic composition of Web services – needs short name!– uses information of previous processes defined to help

the composition of Web services– extract data access pattern and connection pattern

between Web services

Service Registration

UDDI

New Service Creation

Service Recommandation

Service/Data Ontology Process Repository

Service Selection

createservices

register services

searchservices

register services

searchservices analyzed

tuples

adjustment coupling matrix

recommand service

ask recommendation of service

select service

register process

Process Modeling Tool

ProcessAnalyzer

register tuples

BPEL and XPDL

• BPEL(Business Process Execution Language)– execution language– has variables and operations– makes it easy to use several Web services at the same time– doesn’t support the graphics of diagram

• XPDL(XML Processing Description Language)– a process design format– represents the drawing of the process definition– has X&Y coordination and node size

BPEL and XPDL

• Goal– BPEL

• provide the definitions of – Web services orchestration– underlying sequences of interactions– the flow of data from point to point

– XPDL• store and exchange the process diagram• provides the way to exchange the diagram between

process modeling tools

BPEL and XPDL

• Goal

• In design level, XPDL is used for exchange the diagram between tools

• In execution environment, engine uses its own format

BPEL and XPDL

• Paradigm– BPEL(Business Process Execution Language)

• block structured programming language• declaration and definition is possible only at top-level• it is impossible to define the flow out-of-block

– XPDL(XML Processing Description Language)• graph structured language• activity-node, transition-edge• flow is defined as transitions between activities• conditions related transitions define which activities will be executed

at next time– Translation from BPEL to XPDL is more difficult

• For the translation, we need some constraints for well-structured graph

• X&Y coordination, node size, arrow

BPEL and XPDL

• Market trend– BPEL is though as the best BPM standard

• suggested IBM, MS, BEA• The specification will be extend, so BPEL will be supported

by more vendors

BPEL and XPDL

• Oracle BPEL Manager

XPDL and BPEL

• WebVine

BPEL and XPDL

• Implementation our framework– BPEL

• difficult to extract data access pattern

int a = 0;functionA(a);a = 455;functionB(a);

– XPDL• difficult to deal with Web services

How about WebVine?

• Implementation – Java, Eclipse– XPDL

• Issues– Web services support– Processes implemented in XPDL– Extracting information

Conclusion

• We have look over BPEL and XPDL for choosing appropriate language for implementing our framework

• BPEL has advantages in dealing Web services and market power, but it is difficult to implement our framework

• We have very nice platform, WebVine, so I’ll implement our framework based on WebVine

• If we can extends WebVine to support BPEL, it would be more powerful tool