Notes
Outline
Slide 1
Slide 2
Agenda
Emerging Web Services Platform
WS-Choreography & WS-CDL
WS-Orchestration & WSCI/Abstract-BPEL
WS-Choreography & WS-Orchestration
Current Web Services platform
Core communication framework bridging heterogeneous computational models
Loosely-coupled, stateless
Exchange of type checked information
Emerging Web Services platform
WS-Choreography & WS-CDL
WS-Choreography concerns the collaboration protocols of cooperating Web Service participants
WS act as peers
WS interact in long-lived, stateful & coordinated fashion
A WS-Choreography description is a multi-participant contract that describes from a Global Viewpoint the common observable behavior of the collaborating WS participants
WS-CDL is a language in which such a contract is specified
Standardization underway in the W3C Choreography WG
Sample Business Protocol
Choreography: Buyer & Seller collaborate
WS-CDL & WSCI/AbstractBPEL
A WS-CDL description is a multi-participant contract that describes from a Global Viewpoint the common observable behavior of all collaborating WS participants
A WSCI/AbstractBPEL description is a single-participant contract that describes from a Local Viewpoint the observable behavior of a collaborating WS participant
WSCI goes a bit further to wire the contracts together (but only on the operation level)
From WS-CDL contract we can generate a WSCI/AbstractBPEL contract
Then we use the WSCI/AbstractBPEL to write our implementation logic in BPML/ExecutableBPEL
WS-CDL & WSCI/AbstractBPEL
Exchange of a message between 2 participants with common MsgProperties/ Channel/CorrelationSets
Send to a participant/Receive from a participant with Participant specific MsgProperties/partnerLink/ CorrelationSets
Common Reactive Rules for normal/abnormal progress
Participant specific ControlLinks, Event-Handlers
Coordinated progress and agreement of outcome
Participant specific ControlFlow, Exception/Compensation Handlers
Orchestration: Buyer’s observable behavior and Implementation
Orchestration: Seller’s observable behavior and Implementation
Modeling the WS-Business Activity Protocol with WSCI/AbsBPEL: wrong
Choreography & Orchestration together