• XPDL 2.1 Proposals

Support for Remote Subprocess Nodes

|Please note: this is a preliminary proposal for XPDL 2.1 which has not yet been adopted by the coalition. Please use this page for discussion of that proposed extension. This proposal may change substantially before adoption, or may possibly never be officially adopted in this form.

Tags:

• <EndPointReference>URI</EndPointReference>

Context:

• <SubFlow>

Description:

XPDL already has a notion of a "subprocess" node, which is a node in a process, which invokes another process, passing formal parameters to it, and receiving result values back.

The ASAP and WdXML protocols allow for the same sort of interaction with a subprocess which is located remotely, and accessed purely through SOAP calls. The parent process runs on one server, and the subprocess on a different server, possibly implemented with different technology.

This proposal is for an extension to the SubFlow tag, to allow the specification of the "End Pioint Reference" of the remote web service that represents the factory of the subprocess. End Point References is defined by WS-Addressing, and is most commonly appears as a URL but is not necessarily limited to this.

A workflow/BPM engine that understands how to perform a remote subprocess interation will offer in the design tool the ability for the user to specify the URI of the remote process (factory). This URI might be found in any number of ways including being listed on a web page, entered as a UDDI entry, or retrieved using a Wf-XML ListFactories request. The data mapping then is set up in the same way as for a normal subprocess. When this system writes out the XPDL, it will include this new tag in the SubFlow tag. The presence of this tag will indicate that this is a remote subprocess, the omission of it indicates that this is not a remote subprocess.