Collaborating on Design PatternsBy Bob Rhubart
It takes an architect community to raise a collection of SOA design patterns.
To describe Thomas Erl’s recent book, SOA Design Patterns (Prentice Hall Professional, 2009), as a community effort is something of an understatement—like describing Tiger Woods as “a golfer.” The book, along with its companion Web site, SOA Patterns (www.soapatterns.org), is the hub of a collaborative effort, the spokes of which extend into global communities, including the architect community on Oracle Technology Network (OTN).
The culmination of three years’ work, SOA Design Patterns features 85 SOA patterns, reflecting the contributions of 35 pattern authors and a small army of pattern reviewers, collectively representing more than 20 companies and government agencies. The list of people involved in the process reads like a Who’s Who in SOA. It includes some very familiar names representing some very familiar organizations, including Oracle.
Although Erl describes the overall process of organizing the various contributors and reviewers as “altogether crazy,” the decision to include members of the Oracle community was natural, he says, “because of how important Oracle has been to the SOA community.”
Hashing a Grid Pattern
More than a dozen members of the global Oracle community participated in the project, including Oracle Vice President and Chief SOA Technologist David Chappell and Senior Principal Product Manager and SOA Architect Clemens Utschig-Utschig.
Grid computing was Chappell’s point of entry into the SOA Design Patterns project. “It made perfect sense to reach out to David because of his expertise and his presence in that particular field,” Erl says.
Chappell had written two articles on grid-enabled SOA for Erl’s SOA Magazine (www.soamag.com), and according to Erl, those articles were among the magazine’s most popular.
“What especially intrigued me about those articles was how they addressed grid computing within the modern SOA space,” says Erl. He was particularly impressed with how Chappell’s articles illustrated grid computing as an extension of SOA that goes beyond message-oriented middleware to address the critical scalability issues that can affect enterprise-level service-oriented solutions.
“That definitely was one of the factors that led to this collaboration,” says Erl.
Chappell’s Service Grid pattern is included in the book. Three other Chappell patterns—In-Memory Fault-Tolerant Collection, In-Memory Fault-Tolerant Stateful Services, and Load-Balanced Stateful Services—are in the candidate phase. Candidate patterns are published at www.soapatterns.org, where they are subject to an exhaustive community review and validation process before being classified as ready for prime time and added to the site’s master catalog.
Mortaring a Design Foundation
Among the 85 patterns included in the original master catalog that forms the basis of the book are three patterns contributed by the Masons of SOA, an international group of architects that Clemens Utschig-Utschig helped form in 2006.
In keeping with the group’s objective to spread knowledge, foster discussion, and support SOA programs across companies, the Masons of SOA were eager to participate in the SOA design project.
“Getting into this book was something that we wanted,” Utschig-Utschig says. “When it finally worked out, it was an exciting process.”
The group contributed the Compensating Service Transaction, UI Mediator, and Canonical Schema Bus patterns, the last in collaboration with Erl.
Utschig-Utschig and Erl had collaborated on previous books, and more collaboration is on the horizon. Utschig-Utschig and the other Masons of SOA have contributed content to Erl’s upcoming book, Next Generation SOA: A Real-World Guide to Modern Service-Oriented Computing . Utschig-Utschig and Chappell, both ever busy, have also discussed working together on Service Result Cache, another SOA Patterns candidate.
So while Erl’s SOA Design Patterns is already on the shelves, the party is far from over for members of the Oracle architect community, as their contributions to SOA Patterns and other Erl projects continue to extend into the global SOA community.
Bob Rhubart (firstname.lastname@example.org) is manager of the OTN architect community, the host of the OTN Arch2Arch podcast series, and the author of the ArchBeat blog (blogs.oracle.com/archbeat).