Special Guide to SOA Tools: Beyond the Buzz

Service Oriented Architecture is filled with an alphabet soup of concepts such as Business Process Monitoring (BPM), Business Process Execution Language (BPEL) and the Enterprise Service Bus (ESB), combined with other acronyms from the underlying amalgam of Web service technologies. While skeptics argue that this complexity results in a disproportionate amount of money spent with little return, vendors obviously have a different point of view. Some see SOA as the solution that CORBA was supposed to become, while others view it as a natural trajectory of the continued abstraction and evolution of business logic from brittle code to flexible components that can be managed by business analysts. The most progressive advocates foresee additional improvements when SOA is coupled with Model Driven Architecture (MDA). Between the skeptics and the optimists lies reality: SOA is still a relatively new approach to the old problem of effective business automation.

The Moving Parts
Although Web services are all about simplicity, the complexity that has sprouted with their use has made their management far from simple. Monitoring, reporting, provisioning, security, activation, deactivation, reliability and scalability are just a handful of the demands expected from the technology, resulting in the classification of the SOA stack.

WebMethods, for example, defines six areas that its Fabric solution fulfills: Moving up the stack from basic Web services to the user interface, it encompasses services, registry, services management, orchestration, analytics and presentation services. Other end-to-end solution vendors articulate similar associations. Because an SOA stack has so many parts, nearly every vendor featured in this guide emphasizes its product's ease of use. Even with this intent, installing and configuring a product's instrumentation takes an enormous amount of planning and brainpower. While most of the featured products effectively mask the underlying complexity of the services they manage, SOA software companies still have an uphill climb to improve both their products' interfaces and the automatic configuration of discovered Web services within a business process.

A successfully implemented SOA is all about the effective real-time consumption and management of deployed services. These services can be manifested by textbook-designed Web services, wrappers for mainframe screen-scrapes, such as those from NetManage, transacted as Message-Oriented Middleware (MOM) and other autonomic business processes that can be encapsulated inside standards-based XML messages.

To achieve this goal, the categories of components that comprise SOA must interoperate perfectly to activate, inspect and deliver on each component's respective function at an acceptable Service Level Agreement (SLA) level. According to Ian Goldsmith, SOA Software's vice president of product marketing, standards-based, loosely coupled service interoperability is why SOA will be more successful than past distributed computing attempts. And without metrics, it's nearly impossible to accurately assess SLA objectives or conduct any type of continuous improvement efforts. One hurdle facing ubiquitous interoperability is the fact that standards are evolving at different speeds. For example, some third-party Universal Description, Discovery and Integration (UDDI) registry providers don't yet fully support the 3.0 specification. Most vendors advocate using their suites to mitigate the risks associated with the mixing of version-challenged providers—a valid assertion, given the rapid pace of standards evolution.

The SOA Core
While without a registry, services certainly can't be discovered, and without Web services, there would be no SOA, the fact remains that the Enterprise Service Bus (ESB) is the most characteristic element that delineates SOA from a bunch of cobbled-together services. Thinking about a bus in either hardware or software terms evokes images of bits and bytes streaming from departure to destination. David Chappell, chief technology evangelist for Sonic Software, defined ESB in his book Enterprise Service Bus (O'Reilly, 2004) as a "standards-based integration platform that combines messaging, Web services, data transformation and intelligent routing to reliably connect and coordinate the interaction of significant numbers of diverse applications across extended enterprises with transactional integrity." An ESB provider can enhance the base ESB configuration with a number of service enhancements, including security, failover, load balancing and real-time monitoring. Processes that flow through the bus can be orchestrated via Java standards-based BPEL or proprietary constructs that control the execution and trigger the activation of additional services based on predetermined conditions. Clearly, the company and/or technology that can best use and efficiently manage the bus will dominate the market.

Platform, Language Agnostic
Even though SOA is based on Web services that can be written in language-agnostic components, the majority of its products are Java based. This isn't surprising, considering the origin of Web services and the evolution of Java Messaging Service (JMS) as the precursor for the event-driven architecture.

While SOA should be able to consume any well-formed Web service, the majority of enterprise Web services are Java or .NET based. Nearly every vendor featured in this guide either natively resides in or is in the process of fully integrating into the Eclipse IDE. In addition to commercial software tools featuring Eclipse integration, an open Eclipse SOA tools project is building momentum, and several commercial vendors are contributing assets to this project, as well.

With all the attention on the Java centricity of current SOA UIs, only a few companies support an equal degree of native interoperability within Microsoft's .NET-centric Visual Studio IDE. For example, only one of the featured vendors, Portrait Software's Foundation, offers a native SOA add-in for Visual Studio .NET developers.

Open Source Alternatives
Due to SOA's relatively recent emergence and the enterprise-level code investment required to construct such solutions, open source alternatives have been slowly evolving. However, one promising effort is the Apache Synapse project—a coordinated effort by such SOA-centric companies as Blue Titan, Infravio, IONA, Sonic Software and WSO2 to create an open source service broker based on the Apache AXIS2 foundation. The project has not only jump-started open source SOA efforts, it's established a reference platform on which vendors can test and validate interoperability. Infravio has even donated its X-Broker code to the Synapse effort. By creating a reference implementation, these vendors wish to not only promote a platform to test true interoperability between products, but to prime the market with a functioning platform, much as Tomcat energized the commercial Java-based application server market.

Another open source alternative is the J2EE-based ServiceMix, from a distributed team of developers known as Codehaus. Advertised as an open source ESB solution based on the Java Business Integration standard, ServiceMix is available for download under the Apache 2.0 license at http://servicemix.codehaus.org. It'll be interesting to see if ServiceMix becomes the JBoss of the SOA open source market.

There's some speculation that registries in particular will be commoditized over time, the way other standards-based infrastructure services—such as DNS, LDAP and SMTP open source servers—have proliferated in business environments. As such, vendors will continue to improve upon the foundation laid by the standards efforts, just as existing commercial directory and mail service vendors bring their enhanced products to market.

Evaluation Criteria
The biggest challenge in compiling this guide was the rapid introduction of new or upgraded commercial solutions. The selected products represent the state of the art in 2005, but, as with any rapidly moving market, the list will look different even six months from now. In an effort to keep the guide from engulfing half of this issue, I've highlighted vendors who provide primarily comprehensive SOA suites rather than slivers of a total solution.

Features and Claims outlines a product's key features and spotlights the claims that set it apart from its competitors. Some featured companies provided further information by participating in podcasts that can be downloaded from www.sdmagazine.com. Podcast enthusiasts may also be surprised to learn that noted integration specialist and author David Linthicum has been broadcasting the SOA Expert Podcast, available at www.soaexpertpodcast.com. IBM has even joined the podcasting arena, featuring SOA sermons available for download from its developerWorks website.

Market Buzz is based on demonstrations and discussions with the provider, opinions of the editors and in some cases, peer review and/or real-world experience of the product in action. This category subjectively measures the product's "cool factor."

Cost is based on licensing interpretations and required enterprise capacity. In this guide, pricing is relative to the featured product due to packaging and the number of components or separate services the product contains. It's also dependent on the deployment size and varies by company on several factors (number of CPUs, developer versus production licenses, anticipated transaction volume, among others).

Mike Riley ([email protected]) is a Naperville, Illinois-based computing professional specializing in emerging technologies and new development trends.