Beyond Web Services

One of the greatest challenges faced by Web services developers is the fact that the term "Web services" isn't well understood outside the developer community. We've all experienced requests from product managers, customers, or salespeople who had no idea that connecting two disparate systems takes more than a few lines of code. The situation will only get worse with the increased complexity of business-process, transaction, and workflow management.

The use of workflow standards to integrate Web services into a comprehensive, enterprise-wide system is the logical innovation that follows Web services. The challenge is that process management standards must catch up to Web services. The primary impediment is the lack of accepted standards distributed and adapted across the developer community. Just as standards became the foundation for the rise of Web services, they will serve the same function for workflow.

The good news is that the number of serious contenders is limited to three: WSFL, XLANG, and BPML, each with at least one advantage over its rivals. WSFL offers power, XLANG offers simplicity, and BPML offers backing from some strong industry players. Let's take a closer look at each:

WSFL (Web Services Flow Language): An XML-based language that uses directed-graph modeling to define and execute business processes while defining a public interface so business processes can advertise themselves as Web services. Designed by IBM to be part of the Web services technology framework, WSFL complements existing Web services specifications.

XLANG: A fundamental piece of Microsoft's BizTalk server, XLANG is a specification for describing message exchange behavior that allows for automation and tracking of processes exposed as Web services. XLANG is considerably simpler than WSFL, and questions exist about whether it has the technical completeness to handle 100% of workflow use cases. Wholly owned by Microsoft, XLANG is not sanctioned by any standards body.

BPML (Business Process Modeling Language): Another player in the process-management landscape, BPML was submitted in March 2001 by the Business Process Management Initiative, whose heavyweight industry membership includes BEA, Bowstreet, HP, WebGain, Sun Microsystems, and interestingly, IBM.

The next critical step in the adoption of process management is the establishment of a unified standard that combines the best of these three solutions. IBM submitted the WSFL 1.0 specification to the WS-I for review. After extending the spec, the WS-I returned it to IBM, where it remains while Microsoft and IBM discuss the reconciliation of WSFL and XLANG. One potential for unification may be the OASIS work on Business Transaction Protocol (BTP). BTP is intended to be the underlying protocol offering transactional support for the application layer or for a business process management system.

While we wait for the needed integration and standardization, other important steps have been taken that are speeding the diffusion of these process management specifications. In March SilverStream announced the release of its eXtend Composer XML integration server (version 3.5) as the first software to implement WSFL for process management. Siebel Systems, Inc., will follow this summer with its Universal Application Network, which will let users model business processes as reusable objects that plug into any enterprise application integration system. Other companies are certain to quickly follow suit with support for WSFL, clearly indicating the industry's decision to adopt IBM's WSFL specification.

The end result is not as simple as the adoption of WSFL. The sheer power of WSFL adds a layer of complexity that makes it more difficult to grasp and use proficiently, putting mastery beyond the reach of the majority of VB programmers and necessitating the use of powerful tools. The relative simplicity of XLANG is an advantage in this regard, but this specification is simply not powerful enough to drive the varied demands of process management.

In the meantime, companies are adopting WSFL. With IBM in active talks with Microsoft, it's likely that their respective specifications will be melded to create a solution resembing WSFL. Choosing this specification now guarantees standards-based process management in the future without having to revisit the implementation.

The payoff for the unification of process management standards is the power to represent business processes as a workflow connecting applications within the enterprise streamlining their business processes, making daily operations dramatically more automated and efficient, and allowing the monitoring of previously unmonitorable processes. Of course, let's not forget the ultimate promise of Web services - better collaboration between business units. This is the next big opportunity, but it can't happen until we have one industry-supported standard. Thankfully, we're well on the way toward integration and standardization of these process management solutions.

Author Bio
Chris Weaver is VP of technology for Paros Software, Inc. He has created industry-leading software products in the collaborative commerce market for Polycom and VTEL and as a consultant for clients around the world. His research interest at Paros Software is real-time business process collaboration as applied to Web services software. chris@parossoftware.com

Java and Java-based marks are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. SYS-CON Publications, Inc. is independent of Sun Microsystems, Inc.