Web Service Communities: Concepts, Operations, and Engineering

1
Web Service Communities Concepts, Operations,
and Engineering

• Sattanathan Subramanian
• Postdoctoral Fellow
• PReCISE Research Center

2
Road Map

• Introduction
• Community Architecture
• Web Service Community Development Protocol
  (WSCDProtocol)
• Extended Contract-Net Protocol (ECNProtocol)
• Intra- and Inter-Protocol Interactions
• Master Web service Architecture
• Slave Web service Architecture
• Prototype
• Conclusion
• Future Work

3
Introduction

• Web Service
• For W3C, is a software application identified
  by a URI, whose interfaces and binding are
  capable of being defined, described, and
  discovered by XML artifacts and supports direct
  interactions with other software applications
  using XML-based messages via Internet-based
  applications
• Web Service Composition
• Roughly, is about making independent Web
  services interact with one another according to a
  specific business logic that reflects the
  practices in an application domain

4
Introduction (Contd.)

• Web Service Community
• Benatallah et al, 2003 ... a collection of Web
  services with a common functionality, although
  these Web services have distinct non-functional
  properties like different providers and different
  QoS parameters
• Medjahed and Bouguettaya, 2005 ontological
  organization of Web services that share the same
  domain of interest
• Our definition, 2007 to provide a common
  description of a desired functionality (e.g.,
  FlightBooking) without explicitly referring to
  any specific Web service (e.g., EKFlightBooking)

5
Community Architecture

• Master-WS ? it attracts Web services to sign up
  in its community, it nominates the slave
  Web-services that participate in providing
  services upon user requests, and it monitors
  their performance and takes actions in case of
  failure. It leads the community.
• Slave-WS ? provide services to the master
  Web-service upon its nomination, and providing
  support to monitor its presence by the master
  Web-service.

6
Community Architecture (Contd.)

• Some Features are,
• the traditional way of defining, announcing, and
  invoking Web services is still the same although
  these Web services are now elements of
  communities,
• the functionalities that UDDI registries usually
  offer to providers and end users of Web services
  are still the same, and
• the selection of Web services from communities
  is transparent to users and occur independently
  of the way these Web services are gathered into
  communities.

7
WSCDProtocol

• Purpose,establishing a community and managing
  its content of Web services
• Categories of Operations
• WS-Attraction ? operations 1 to 4,
• WS-Registration ? operations 5 and 6,
• WS-Withdrawal ? with operations 7 and 8

8
ECNProtocol

• Purpose, in identifying the slave Web-service
  that will handle user's request and second, in
  following the performance of this request
• Categories of Operations,
• ContractAgreement ? operations 1 to 4,
• ContractCompletion ? operations 5 and 6.

9
Intra- and Inter-protocol Interactions
10
Master Web service Architecture
11
Slave Web service Architecture
12
Sequence Diagram
13
Prototype

• It is developed to experiment WSCDProtocol and
  the
• ECNProtocol, using the following
• XML for request and response specification
  between users and Web services and between master
  Web-services and slave Web-services
• JDK 1.4 for operation processing, and
• Eclipse 3.2 as an integrated development
  environment.
• Weather Community is used for illustration
  purposes

Scenarios Web services registration
14
Prototype (Contd.)
Responses from the slave Web-services to the
master Web-service's call for bids
Selection of slave Web-service
15
Conclusion

• Our project on Web services communities addressed
  several aspects including establishing/dismantling
  a new/existing community, attracting new Web
  services to an existing community, retaining
  existing Web services in a community, and
  regulating the interactions inside a community.
• It also laid down the foundations upon which the
  process of engineering communities of Web
  services would take place.

16
Ongoing work

• The present version of WSCDProtocol is not
  considering the policies of Web service community
  during the Web service attraction. For instance,
  the policy of community can have a set of
  functional (like weather) and non-functional
  (like security, quality of service, compensation)
  aspects for defining its working nature. So it
  opens the following questions
• How a master Web service can define a policy for
  community?
• How a master Web service can get a new slave Web
  service based on the policy of community?
• How a master Web service can handle the situation
  when it can find a new Web service which
  partially match the community policy but the new
  one is looking promising?
• How a master Web service can handle the situation
  when it can find a new Web service which can
  match the community policy completely but with
  additional requirements/expectations?
• How a master/slave Web service can handle the
  situation when the slave/master Web service comes
  up with new policy proposal?
• Can the policies of two slave Web services in
  conflict? If so, how the master Web service can
  handle this?

17
Related Publications

• S. Subramanian, P. Thiran, Z. Maamar, and D.
  Benslimane. 'Engineering Communities of Web
  services', The 9th International Conference on
  Information Integration and  Web-based
  Applications and Services (iiWAS-2007), Jakarta,
  Indonesia. 
• Z. Maamar, M. Lahkim, D. Benslimane, P. Thiran,
  and S. Subramanian. 'Web Service Communities
  Concepts and Operations', 3rd International
  Conference on Web Information System and
  Technology (WEBIST-2007), 3-6 March 2007,
  Barcelono, Spain.

18
Selected References

• Benatallah, B., Sheng, Q. Z., and Dumas, M.
  (2003). The Self-Serv Environment for Web
  Services Composition. IEEE Internet Computing,
  7(1).
• Medjahed, B. and Bouguettaya, A. (March 2005). A
  Dynamic Foundational Architecture for Semantic
  Web Services. Distributed and Parallel Databases,
  17(2).

19
Questions?
20
Thank you!