16.3 Service Oriented business process design The last overall step in Service Oriented Business

process designGoal is to map the business processes completely

All expected process flows are mappedAll exception conditions are anticipated and

accommodatedTraditionally work split

business analysts modeled processesIt 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

Review existing design productsPrevious design steps created the products

needed to model the business processes and create the orchestrationComposition diagramsService CandidatesService designsWorkflow logic produced modeling services

Map out interaction scenariosInteraction between process and partner

servicesCreate activity diagrams

Diagrams of successful processesDiagrams of unsuccessful processes

List messages to be processed by each serviceIncoming messagesOutgoing messages

Design the process service InterfaceCreate WSDL process service definitions

Typically using modeling toolsCan 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

Formalize partner service conversationsDescribe the role of each partner service in a

message exchangeAdd partnerlinkType constructs to the service

WSDL definitionsCreate partnerLink elements for each partner

service in the process definitionDefine variable elements for messages sent

and received with partner servicesThis comprises the possible message flows in

the process execution

Define Process LogicCreate a WS-BPEL process definition

Implements the original workflow logicEncompasses processing requirements

Activities Fault handling

Covers all the service interaction scenarios

Iterative reviewCheck your step 1 interaction scenarios and

ensure the WS-BPEL reflects the process logic succinctlyEnsures the original interactions scenarios are

completePossibly leads to the discovery of new fault or

exception conditions that need to be included in the WS-BPEL

Look for opportunities to consolidate activitiesClean up markup code for readability and ease of

maintenance

SummaryBusiness Process design comes lastPrevious design products are used in processThe service interface and process definition are

createdGraphical 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.

More informationWS-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 Languagehttp://www.ibm.com/developerworks/edu/ws-dw-ws-understand-web-services7.html

WS-BPEL on apache – ODE (Orchestration Director Engine)http://www.ibm.com/developerworks/opensource/

library/os-eclipse-bpel2.0/