Semantic Web Services-based
Reasoning in the Design of
Software Product Lines
J. Jeffrey Rusk
Research Goals
• Encode product configurations from SPL as
compositions of Web Services
• Enable reasoning approaches to facilitate higher
automation of:
o Service Discovery
o Service Composition
o Service Invocation
• Evaluation of Web Service Modeling Ontology (WSMO)
for the above purposes
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Motivation
• The need to manage variability in SOA designs
• Impediments to SPL when considering SOA
• Improve Web service discovery, composition, and
invocation while retaining the benefits of the SPL approach
3
Presentation Outline
• Background
o Software Product Lines and Feature Models
o Semantic Web Services and WSMO
o Orchestration and Choreography
• Design and Implementation
o Summary of Mappings
o Structure of Feature Model
o Transformation in ATL
o Manual Intervention
o Reasoning in WSMX
• Running Case and Demonstration
• Results
• Conclusions
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Background
An approach to integrate the typically non-related fields of:
• Software Product Lines
• Service Oriented Architecture
Leveraging a number of existing approaches:
• Feature Modeling
• Ontologies (Web Service Modeling Ontology)
• Model Driven Development
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Software Product Lines
• The concept of software product line (SPL).
• Exploitation of commonality and management of variability
• SPL practices, methodologies, and key features
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Feature Models
• Feature diagram and types of features
• Relationships and Constraints
• Attributes
Feature Model Example
Feature Model Metamodel
Adapted from Kim and Czarnecki (2005)
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Semantic Web Services
• Web Services and Semantic Descriptions
• Relation to Ontologies and Reasoning
• (Semi-)Automated discovery, composition, invocation, and
monitoring
• Semantic Descriptions vs. WSDL-based Descriptions
• The “Semantic Web” (Berners-Lee et al. 2001)
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Web Service Modeling Ontology
(WSMO)
• Semantically describes all relevant aspects of Semantic
Web Services (Roman et al. 2005)
• Four top-level elements:
o Ontologies, Web Services, Goals, and Mediators
Abbreviated WSMO Metamodel
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Choreography and Orchestration
• Orchestration: overall executable business process
defined through interaction between Web services
• Choreography: sequencing of messaging between such
executable business processes
•
•
•
•
Suitability of Orchestration
Use of choreography to achieve orchestration
Invoking Web services through grounding in choreography
Examples in the literature (Gone and Schade 2008;
Brambilla et al. 2007)
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Design and Implementation
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Summary of Mappings
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Structure of Feature Models
Basic rules from Montero et al. (2008) allow business
process information to be represented in the feature model.
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Transformation in ATL
•
•
•
•
Creation and loading of source and target metamodels
Creation of textual concrete syntax for WSML
Navigation of feature model using ATL
Output of partial WSML Web service description
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Manual Intervention
importsOntology _"http://io.acad.athabascau.ca/~jeffr#virtual"
// TODO: Import Any Domain Ontologies Used
______________________________________________________________________
capability VirtualWholesaleCompositionCapability
sharedVariables {} // TODO: Any Shared Variables of Capability
precondition definedBy.// TODO: Preconditions of First Service
postcondition definedBy.// TODO: Postcondition of Final Service
______________________________________________________________________
transitionRules VirtualWholesaleCompositionTrules
// AtlanticTech Web Service
forall {?controlstate} with(
?controlstate[oasm#value hasValue oasm#InitialState] memberOf oasm#ControlState)
do
forall with()
do
// TODO: AtlanticTech Related Transition Rules
endForall
delete(?controlstate[oasm#value hasValue oasm#InitialState] memberOf
oasm#ControlState)
add(?controlstate[oasm#value hasValue oasm#State1] memberOf oasm#ControlState)
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endForall
Sources of Executable WSML
WSMO Component
Source
wsmlVariant and namespace
Transformation (+ constants)
webService
Transformation
nfp
Transformation and Manual Intervention
importsOntology
Transformation and Manual Intervention
capability
Transformation
sharedVariables
Manual Intervention
precondition
Manual Intervention
postcondition
Manual Intervention
interface
Transformation
choreography
Transformation
stateSignature
Transformation
transitionRules
Transformation and Manual Intervention
OASM Ontology
Transformation and Manual Intervention
Reasoning in WSMX
Service Invocation by WSMX
---------Outgoing SOAP message--------<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope xmlns:SOAPENV="http://schemas.xmlsoap.org/soap/envelope/">
<SOAP-ENV:Header/>
<SOAP-ENV:Body>
<atl:returnPrice xmlns:atl="http://atlantictech.wsmo/">
<arg0>1</arg0>
</atl:returnPrice>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
----------End of SOAP message------------------Incoming SOAP message--------<?xml version="1.0" encoding="UTF-8"?>
<S:Envelope
xmlns:S="http://schemas.xmlsoap.org/soap/envelope/">
<S:Body>
<ns2:returnPriceResponse
xmlns:ns2="http://atlantictech.wsmo/">
<return>545.32</return>
</ns2:returnPriceResponse>
</S:Body>
</S:Envelope>
----------End of SOAP message----------
Process Mediation in WSMX (Choreography)
INFO Machine : STEP 1
INFO Machine : Executing
forall {?controlstate} with
(?controlstate[_"http://www.wsmo.org/ontologies/choreog
raphy/oasm#value" hasValue
_"http://www.wsmo.org/ontologies/choreography/oasm#I
nitialState"] memberOf
_"http://www.wsmo.org/ontologies/choreography/oasm#C
ontrolState") do
add(?controlstate
[_"http://www.wsmo.org/ontologies/choreography/oasm#
value" hasValue
_"http://io.acad.athabascau.ca/~jeffr#State1"])
forall {?input,?request} with
(?request[_"http://io.acad.athabascau.ca/~jeffr#quantity"
hasValue ?input] memberOf
_"http://io.acad.athabascau.ca/~jeffr#ProducerRequest")
do
add(_# memberOf
_"http://io.acad.athabascau.ca/~jeffr#ProducerResponse
")
add(_#
[_"http://io.acad.athabascau.ca/~jeffr#quantity" hasValue
?input] memberOf
_"http://io.acad.athabascau.ca/~jeffr#ShipperRequest")
endForall
delete(?controlstate
[_"http://www.wsmo.org/ontologies/choreography/oasm#
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value" hasValue
Running Case and Demonstration
• Hypothetical B2B “Virtual Wholesale” Scenario
• 4 producer, 4 shipment, 3 insurance, 2 credit card SOAPbased Web services
• Feature Model used to manage the variability
• Product configuration represents a potential composition
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Results
INFO WSMXExecution
: Retrieved Goal: http://io.acad.athabascau.ca/~jeffr#VirtualWholesaleGoal
INFO WSMXExecution
: Retrieved Goal Ontology: http://io.acad.athabascau.ca/~jeffr#VirtualWholesaleGoal
INFO AchieveGoalChor : Discovering suitable webservices for: http://io.acad.athabascau.ca/~jeffr#VirtualWholesaleGoal
INFO KeywordDiscovery : Keyword discovery - operating on 42 services.
INFO LightweightDiscovery : Testing Web service http://io.acad.athabascau.ca/~jeffr#VirtualWholesale
INFO AchieveGoalChor : --- Performing Data Mediation; direction: GOAL_TO_WEBSERVICE
INFO AchieveGoalChor : ----------- Mediated instances ----------INFO AchieveGoalChor : http://io.acad.athabascau.ca/~jeffr#myCompositionProduct memberOf
http://io.acad.athabascau.ca/~jeffr#ProducerRequest
INFO Radex
: Registering requester choreography
INFO Radex
: Registering provider choreography
INFO LogicalState
: Initializing state http://www.wsmx.org/choreography/state_id-0at3062331014347694380#onto
_____________________________________________________________________________________________________
INFO AchieveGoalChor : ----------- Final response to requestor ----------namespace { wsml _"http://www.wsmo.org/wsml/wsml-syntax#" }
ontology _"http://wsmx.org//responseOntology1783308446288430806"
instance _"http://wsmx.org//responseOntology1783308446288430806#tempInst1249566819733_-731343865"
memberOf _"http://io.acad.athabascau.ca/~jeffr#PaymentResponse"
_"http://io.acad.athabascau.ca/~jeffr#value" hasValue "true"
INFO AchieveGoalChor: --- Performing Data Mediation; direction: WEBSERVICE_TO_GOAL
INFO AchieveGoalChor: ----------- Mediated instances ----------INFO AchieveGoalChor: http://wsmx.org//responseOntology1783308446288430806#tempInst1249566819733_-731343865
memberOf http://io.acad.athabascau.ca/~jeffr#PaymentResponse
INFO WSMXExecution : TIME TAKEN: 3362 ms.
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INFO WSMXExecution : FINISHED AT 10:53:39
Analysis
• Provision of semantic reasoning-based information
• WSMX output, while verbose, returns significant
reasoning-based information to the developer
• Results of keyword-based and lightweight discovery,
data mediation, and process mediation
• Information not available in the feature modeling
environment alone
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Evaluation
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•
•
•
Productivity
Ease of Use
Scalability
Performance
Average Percentage of Automation
WSML Component
Web Service Description
Percentage Automatically Generated
76%
Capability
47%
Interface
82%
Goal Description
74%
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Comparisons
• Automation compared to Brambilla et al. (2007)
• Focus of reasoning compared to Wang et al. (2007)
• Opportunity to annotate feature model with additional
information to improve automation; comparisons to Kaviani
et al. (2008) and Mohabbati et al. (2009)
• Other comparisons
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Contribution and Uses
• Set of mappings and an ATL transformation between
feature model and WSMO formalisms.
• KM3 metamodel of the WSML language (WSML-Flight
variant)
• Textual concrete syntax for WSML
• Files available to be used as is, improved, or extended for
other MDD purposes involving the WSMO language
• Further example how SOA and SPL approaches can be
integrated to achieve greater results
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Conclusion
• Review of objectives
• Proof of concept demonstrating that it is possible to
integrate feature model and WSMO formalisms
• Ability to facilitate Semantic Web-based reasoning in the
design of software product lines, specifically those
comprised of Web services
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Future Research
• Contributions to tool support and specifications.
• Revise transformation upon completion of WSMO
Orchestration specification.
• Combine transformation with access to a discovery
engine to feature model Goals instead of known Web
services.
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Thank you!
Questions?
Jeff Rusk
MSc Candidate, Athabasca University
jrusk2006@hotmail.com
More information, including all source code, can be found at the following
Website: http://io.acad.athabascau.ca/~jeffr/webdoc.html
Acknowledgements
The author acknowledges the support of the Alberta Ingenuity Fund as well as
Athabasca University through the Graduate Student Research Fund.
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