7.7 Flow languages

 < Day Day Up > 



7.7 Flow languages

This section discusses the business process languages relevant to the WebSphere Process Choreographer and WebSphere MQ Workflow Process Managers:

  • Flow Definition Language (used by WebSphere MQ Workflow)

  • Flow Definition Markup Language (used by WebSphere Process Choreographer)

  • Business Process Execution Language for Web Services

7.7.1 Flow Definition Language

Flow Definition Language (FDL) is a text based process definition format that provides an interface between process modeling and development tools, and the process engine of WebSphere MQ Workflow.

An FDL document describes the make-up of a process flow. Although theoretically FDL could be written by hand, it is commonly generated using WebSphere MQ Workflow Buildtime. As FDL became an established standard, other process modeling and development tools came on the market that were capable of exporting FDL, thus suitable for use with WebSphere MQ Workflow. This included third parties such as Holosofx®, who have since been acquired by IBM. The Holosofx product is now marketed as IBM WebSphere Business Integration Workbench, and offers facilities to generate FDL.

7.7.2 Flow Definition Markup Language

Despite its name, which sounds similar to FDL, Flow Definition Markup Language (FDML) is actually based on the Web Services Flow Language (WSFL) standard introduced by IBM. FDML introduces extensions to the WSFL standard and is the flow language used to describe a WebSphere Process Choreographer process.

WebSphere Studio Application Developer Integration Edition uses FDML to describe WebSphere Process Choreographer business processes.

FDML describes the behavior of the process. It is an XML based format. An FDML file describes elements of a process such as the flow model, activities, control links, compensation, messages, and variables.

A sample of an FDML file is shown in Example 7-1.

Example 7-1: Sample FDML file

start example
 wf:flowModel autoDelete="true" canRunInterrupted="true"         canRunSynchronous="false" name="EventCompensationProcess"         requiresCompensationSphere="true" validFrom="2003-01-01T12:00:00">         <wf:messageType name="MessageType_11" typeSystem="WSDL2">             <service:messageRef name="processOrderInput" namespace="http://process.itso.ibm.com/">                 <service:import location="file:com/ibm/itso/process/EventCompensationProcessInterface.wsdl"/>             </service:messageRef>         </wf:messageType> 
end example

For more information about FDML, please refer to the IBM Redbook WebSphere Version 5 Web Services Handbook, SG24-6891.

7.7.3 Business Process Execution Language for Web Services

Business Process Execution Language for Web Services (BPEL4WS) is another notation for describing business process behavior, based on Web Services. Processes in BPEL4WS export and import functionality by using Web service interfaces exclusively. It represents a convergence of the ideas in the Microsoft's XLANG and IBM WSFL specifications. Both XLANG and WSFL are superseded by the BPEL4WS specification.

BPEL4WS allows specifying business processes and how they relate to Web services. This includes specifying how a business process makes use of Web services to achieve its goal, as well as specifying Web services that are provided by a business process. Business processes specified in BPEL4WS are fully executable and portable between BPEL4WS-conforming environments. A BPEL4WS business process interoperates with the Web services of its partners, whether or not these Web services are implemented based on BPEL4WS. Finally, BPEL4WS supports the specification of business protocols between partners and views on complex internal business processes.

Future IBM product offerings may adopt the BPEL4WS standard, or an extension of it. The BPEL4WS specification is available at:

  • http://www.ibm.com/developerworks/webservices/library/ws-bpel/

For more information about BPEL4WS, please refer to the IBM Redbook WebSphere Version 5 Web Services Handbook, SG24-6891.



 < Day Day Up > 



Patterns. Broker Interactions for Intra- and Inter-Enterprise
Patterns. Broker Interactions for Intra- and Inter-Enterprise
ISBN: N/A
EAN: N/A
Year: 2004
Pages: 102

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net