Web services show great promise as a standards-based way to expose heterogeneous platform business processes and attain ever-elusive visibility into system architectures. But too many unresolved questions and issues remain surrounding security, federation, policy, trust, and other business-to-business protocols for it to become the defacto integration tool of choice, said Peter Linkin, senior director of product marketing for BEA's WebLogic Integration team.
Also, Web services are limited in functionality, said Itamar Ankorion, director of product management at Attunity, which develops custom APIs (application programming interfaces) for integration vendors such as webMethods and Tibco.
Traditional integration approaches are still required to expose the business logic, processes and data housed in such mission critical applications as ERP, SCM, and CRM. Simply wrapping data in XML is enough to allow it to be exchanged as a Web service, but more involved functionality, such as exposing an entire business process to a supplier, for example, still requires traditional integration approaches on the back end.
If, for example, integration of two back-end systems is required to supply the CRM system with real-time customer order and tracking information, many, many calls to the SCM and ERP systems will be required. Doing this via Web services wouldn't work well because it is too slow, said Ankorion. In this instance, a point-to-point approach would work better.
[Correction: Attunity's adaptors would handle calls to the legacy systems supporting the SCM and/or ERP applications, not the applications themselves.]
"These types of processes, in order to capture them and define them and model them and do the heavy transformation they require, that's when you would use an EAI (enterprise application integration) broker" like a Vitria or Tibco, said Ankorion.
[Clarification: "broker" should reference such integration tools as BEA Weblogic Integration or Micosoft's BizTalk server not integration companies.]
The one big "but," though, is if business processes are built out on a Web services-friendly platform like J2EE or .NET. Then exposing those processes is a much simplier process and may not require any traditional integration, especially if the data is wrapped in XML, said John Kiger, also a director of product marketing at BEA.
"If you build natively on J2EE then you have, as an application developer, the ability to expose application functionality via Web service," he said.
Or, for more transaction-heavy types of integration where a J2EE solution requires the services of a non-J2EE application, it is possible to also expose functionality through an adaptor, he said.
Lingering Legacy Code
As far as adoption goes, there is still a lot of legacy code to deal with, so (as always) inertia is an issue. With so much invested in Y2K remedies and enterprise-wide solutions over recent years, companies are reticent to go out and latch onto a new technology when they are still trying to absorb the old, said Dean Nelson, practice leader for Integration Development and Infrastructure at Deloitte & Touche Consulting.
"In some circles Web services is still out there on the bleeding-edge," said Nelson. "A lot of organizations are still kind of trying to get their arms around EAI technology in the broadest terms. So, moving them into third- or fourth-generation thinking around integration is a long way for a lot of organizations. It's an interesting conversation but it's not one they're willing to bet their career on."
Eventually, adoption lag will catch up with the technology, said BEA's Linkin. It's just a matter of time, money and a willingness to embrace Web services as the first real attempt to bridge the chasms between proprietary systems running on hostile platforms.
"Today you really can't do grown-up enterprise integration with Web services," he said. "(Web services) is useful and has a huge potential down the road because that hopefully is the first decent shot at something that's cross-vendor and cross-fiefdom."
Until then, though, Web services should be viewed as just another tool in the kits of both integrators and developers, said Attunity's Ankorion.
"Today, other APIs provide better support for transactions and security and performance, and that's the reason people are still using it," he said. "As we move forward and Web services start providing that, people will start using it."