16'3 Service Oriented business process design

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16.3 Service Oriented business process design

• The last overall step in Service Oriented
  Business process design
• Goal is to map the business processes completely
• All expected process flows are mapped
• All exception conditions are anticipated and
  accommodated
• Traditionally work split
• business analysts modeled processes
• It architects and developers built the services
• WS-BPEL makes it possible for the same person to
  model the process flow while creating the process
  service in the orchestration layer

2
Review existing design products

• Previous design steps created the products needed
  to model the business processes and create the
  orchestration
• Composition diagrams
• Service Candidates
• Service designs
• Workflow logic produced modeling services

3
Map out interaction scenarios

• Interaction between process and partner services
• Create activity diagrams
• Diagrams of successful processes
• Diagrams of unsuccessful processes
• List messages to be processed by each service
• Incoming messages
• Outgoing messages

4
Design the process service Interface

• Create WSDL process service definitions
• Typically using modeling tools
• Can usually be edited by hand to ensure
• All Input and output values required are included
• The portType area includes all operation
  constructs
• Meta information has been included using the
  documentation element

5
Formalize partner service conversations

• Describe the role of each partner service in a
  message exchange
• Add partnerlinkType constructs to the service
  WSDL definitions
• Create partnerLink elements for each partner
  service in the process definition
• Define variable elements for messages sent and
  received with partner services
• This comprises the possible message flows in the
  process execution

6
Define Process Logic

• Create a WS-BPEL process definition
• Implements the original workflow logic
• Encompasses processing requirements
• Activities
• Fault handling
• Covers all the service interaction scenarios

7
Iterative review

• Check your step 1 interaction scenarios and
  ensure the WS-BPEL reflects the process logic
  succinctly
• Ensures the original interactions scenarios are
  complete
• Possibly leads to the discovery of new fault or
  exception conditions that need to be included in
  the WS-BPEL
• Look for opportunities to consolidate activities
• Clean up markup code for readability and ease of
  maintenance

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Summary

• Business Process design comes last
• Previous design products are used in process
• The service interface and process definition are
  created
• Graphical modeling tools alleviate the need to
  know WS-BPEL and WS-Coordination syntax, but
  knowledge of the elements is essential
• The design process is best seen as iterative with
  value added in streamlining, maintainability and
  optimization achieved through reviewing the
  WS-BPEL resultant document against the original
  workflow and previous SOA design products.

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More information

• WS-BPEL 2.0 Official Primer on Oasis
• http//www.oasis-open.org/committees/download.php/
  23964/wsbpel-v2.0-primer.htm
• IBM Online - Understanding Web Services
  specifications, Part 7 WS-Business Process
  Execution Language
• http//www.ibm.com/developerworks/edu/ws-dw-ws-und
  erstand-web-services7.html
• WS-BPEL on apache ODE (Orchestration Director
  Engine)
• http//www.ibm.com/developerworks/opensource/libra
  ry/os-eclipse-bpel2.0/