STANDARDIZE WORKFLOW DATA WITH WF-XML

Many organizations strive to reduce costs by streamlining their 
business
processes. One method that helps improve process management is workflow
automation. By creating systems that automate the process of moving
business data from one step in the process to another, an organization 
can
reduce the overhead costs that go along with manual tasks.

In an effort to help understand and standardize various aspects of
managing workflow, the Workflow Management Coalition (WfMC) was 
created. One
of the WfMC's standards is Wf-XML, which is an XML approach to 
regulating
workflow data.

OVERVIEW

One of the goals for Wf-XML is to provide an interoperability interface
between multiple workflow systems. This means allowing an organization 
to
communicate with another organization via their respective automated
workflow systems. This is important for many business-to-business
environments where multiple companies need to communicate in order to 
complete a
solution. Wf-XML supplies the interoperability interface that the 
workflow
systems will use to communicate.

There are various components that make up the complete Wf-XML
specification. Obviously, there is a component that defines the various 
XML
elements that you can use to compose Wf-XML documents. Wf-XML is 
designed to be
used when multiple systems are interacting. To this end, Wf-XML expects 
a
certain infrastructure to handle the transport and implementation of 
the
XML documents.

Because Wf-XML needs to allow systems to operate together, the HTTP
protocol lets you communicate documents between systems. If you're 
familiar
with HTTP, then you know that it is built around a request/response 
model.
This means that an HTTP request to a server initiates every 
interaction.
When the server receives the request, it processes the incoming 
document
and provides the results of the request in another XML document
encapsulated by an HTTP response. Your organization can use HTTPS if 
there is a
concern about the workflow interface. Wf-XML can also support other
transport mechanisms such as e-mail, TCP/IP network connections, and 
Message
Oriented Middleware (MOM).

Wf-XML allows a system to interact with a workflow system to carry out 
a
variety of tasks. The system that is using Wf-XML to communicate with
the workflow system can send an XML document to create a new workflow
process, determine the progress of an existing process, and receive
notification about the changes in an existing workflow process.

DETAILS

While Wf-XML is using HTTP as its document transport mechanism, it does
not always use a synchronous request/response method. Some workflow
interactions are based on synchronous request/response mechanisms, in 
which
case the request and response are synchronized through the HTTP 
protocol.
However, there are cases where one system may simply send a document to
another system and not expect a synchronous response (if it even 
expects a
response). This method still uses the HTTP protocol to accept the
incoming data, and the response is negligible.

When the response is coming back to a system in an asynchronous
scenario, how the transfer of data occurs is less obvious. In this 
case, the
context is a little broader. Rather than a single HTTP server, the 
context
includes two HTTP servers--each representing the interface for the
respective workflow systems. When the response from an asynchronous 
request is
"ready," it is sent to the other HTTP server, and now the HTTP request 
is
actually the response from the other system.

Each of the tasks that are available via Wf-XML are encoded as XML
documents. We can categorize the three operations available as 
registration,
reference, and control.


* The registration operation allows a system to send Wf-XML requests 
and
responses.

* The reference operations include functionality for asking for and
sending the status of a previous Wf-XML request.

* The control operations provide cancel, stop, and resume requests and
responses related to previous Wf-XML requests.


Brian Schaffner is a senior consultant for DMR Consulting, a Fujitsu
company. He provides architecture, design, and development support for 
DMR's
Telcom360 group.

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