The Workflow Management Coalition (WfMC) Working Group 4 is assembling a demonstration of products that have implemented the Wf-XML protocol. We are looking for people interested in observing this demonstration.

Here are the slides (1MB zipped) from the live demonstration which took place on Monday, February 28, 2006. This demo was repeated on March 11 at 0800 Pacific time with online observers only.

• What is the relationship between Wf-XML and ASAP
  Wf-XML is designed and implemented as an extension to the OASIS Asynchronous Service Access Protocol. ASAP provides a standardized way that a program can start and monitor a program that might take a long time to complete. It provides the capability to monitor the running service, and be informed of changes in its status. Wf-XML extends this by providing additional standard web service operations that allow sending and retrieving the “program” or definition of the service which is provided. A process engine has this behavior of providing a service that lasts a long time, and also being programmable by being able to install process definitions.

• Why do we need a standard protocol for this?
  Because it is anticipated that process editing tools and process execution tools might be produced by different vendors. A standard way to retrieve process definitions and send definitions will allow a user to match the best process definition tool with the best process execution engine for their needs. We already have groups defining process languages to give a common way to express a particular process definition. Wf-XML completes the job by giving a standard way to pass the process definition between the design tool and the execution engine

• Where did Wf-XML come from?
  The roots of the current effort began in 1997 with the Internet Engineering Task Force (IETF) effort named Simple Workflow Access Protocol (SWAP) lead by Netscape, Oracle and others. This was followed by the WfMC standard known as WfXML 1.0 and WfXML 1.1. Wf-XML was implemented by a number of commercial products. Because it was invented before SOAP, it does not use SOAP message structures. ASAP and WfXML 2.0 are efforts to move the same capability to be on top of SOAP messages, and to conform to other web standards that have come into existence in the mean time.

• What would Wf-XML be used for?
  Wf-XML is an ideal way for a BPM engine to invoke a process in another BPM engine, and to wait for it to completed.

• How can Wf-XML be used by BP Design Tools?
  Wf-XML provides a standard way to retrieve a process definition from a BPM engine, and to provide an updated one to the BPM engine. A process design tool could used this standard web services based protocol to browse processes on remote BPM server. It provides an interface between such a design tool and the BPM engine; this is the traditional WfMC Interface 1 for getting and setting the process definition. There is no other effort known to be proposed for standardizing this interaction.

• Does the protocol automatically convert the Process Definition Format?
  No. The protocol merely communicates the process definition to and from the client and server. The process design tool and the process engine must be able to agree on a format to exchange.

• How hard is it to implement?
  At this point the underlying SOAP support is readily available, and because this uses web service technology in a normal way, it is quite easy to implement the 4 or 5 web service operations that are needed.

• Is it really a web service?
  The common definition of a web service is that the messages that are to be exchanged are defined using WSDL. Since Wf-XML 2.0 is defined using WSDL, we say that Wf-XML is a standard web service. We have been careful to assure this because only by strict adherence to the standard can we have the best chance to benefit from all the other work being done on web service standards.

• Is it compatible with Wf-XML 1.1?
  No. The earlier protocol was not based on SOAP messages. While it is based on many of the same ideas, we felt the conformance to SOAP standards was more important than ability to co-operate with earlier versions of the protocol.

• Who is sponsoring the Demonstration of Wf-XML?
  The Workflow Management Coalition (WfMC) is making the arrangements for the demonstration, and the publication of the results.

Any additional questions - please email Keith Swenson.