Thomas Erl's long-awaited ''SOA Design Patterns'' [Prentice Hall, 2008] has hit the book stores. It arrives after undergoing an interesting editing process in which patterns of SOA development were posted to a community Web site for comments and vetting.
Patterns are established ways of solving problems; re-usable solutions, if you will. They first gained currency based on the work of Christopher Alexander, who applied patterns to building architecture. Software architects led by the software Gang of Four [Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides] took these ideas forward in the realm of systems design.
Now, SOA is ready for a full design pattern treatment.
Erl has been among the leading voices in SOA from the get-go. Among his other books are ''Service-Oriented Architecture: Concepts, Technology'' and ''Design and Service-Oriented Architecture: A Field Guide to Integrating XML and Web Services.''
This latest book, says Erl, is a part of a bigger effort to establish a defacto library for SOA. While creating that library, he notes, he has been able to work with preeminent experts in the industry. Contributors to ''SOA Design Patterns,'' for example, include Anish Karmarkar, Mark Little, Satadru Roy and David Chappell, among many others. Erl intends the books to be true technical guides that ''actually get down into the nitty gritty of things.''
''SOA Design Patterns'' is the fifth book in the series, and five more are presently under development. There are 85 design patterns in the new book. They are described fully, and their presentation in turn adheres to a regular documentation pattern.
"My number-one concern was making sure what ended up in the book was verified in terms of being patterns that directly supported SOA and services, and were directly part of that whole platform," said Erl.
Erl covers SOA design patterns including Agnostic Context, Atomic Service Transaction, Data Format Transformation, Service Agent, Service Decomposition, Trusted Subsystem and many more.
It is as hard to ask for a favorite pattern in such a collection as it is to ask for a favorite child in a family. But we did. In turn, Erl highlighted the Domain Inventory pattern. It deals with the problem of establishing a single enterprise service inventory – always a tense task for a business. When applied, the Domain Inventory pattern allows services to be grouped into manageable, domain specific inventories. These can be independently standardized, governed and owned, as needed.
SearchSOA.com will continue to cover elements of ''SOA Design Patterns'' throughout 2009. Stay tuned!
Related SOA design patterns information
''SOA Design Patterns'' book site - www.soapatterns.com
Site to support the on-going expansion of the SOA design patterns catalog – www.patterns.org
Thomas Erl on service orientation – SearchSOA.com