Service Component Architecture spec promises to make SOA easier

May 1, 2008 (InfoWorld) Service Component Architecture (SCA), a service-oriented architecture (SOA) specification for transforming IT assets into reusable services, was hailed this week as a way to build services with lower barriers to adoption and link SOA to Web 2.0.

Speaking at the OASIS Open Standards 2008 symposium in Santa Clara, Calif., Mike Edwards, co-chair of the Organization for the Advancement of Structured Information Standards SCA Assembly Technical Committee, touted the technology. He also promoted its companion specification, Service Data Objects (SDO), which enables uniform access and manipulation of data from multiple sources, including databases and enterprise information systems. SDO and SCA are backed by companies including IBM and SAP AG.

"SCA makes life simpler because it gets rid of the details of how things are accessed, where endpoints are located," said Edwards, who is also a strategist in the emerging technologies group at IBM.

SCA provides an executable model for assembling services and supports multiple languages such as BPEL (Business Process Execution Language for Web Services), Java and PHP scripts, he said.

"It's simplified because it has this principle of removing middleware APIs," said Edwards, referring to application programming interfaces.

Web 2.0 could leverage SCA, since Web 2.0 environments are typically service environments, Edwards said. An interactive application running on a browser has pieces running on the front end that require knowledge of connections pertaining to what is running on the front-end system and the server. SCA "is a great way to deal with that," he said.

SCA offers a single programming model for aspects of the service life cycle, including construction, assembly and deployment. Developers can focus on writing business logic.

Also, developers are saved from having to learn more and more interfaces. "With SCA, you don't need to do that," Edwards said.

SCA is not tied to a specific programming language, protocol, technology or runtime. It is not a workflow model such as BPEL, and it is not a Web service -- although many SCA applications will use Web services, Edwards explained.

In addition, SCA is not an ESB (enterprise service bus). "SCA is really about the programming of applications and the ESB is the infrastructure on which those applications will run," he said.

SDO, meanwhile, gives developers a single programming model for using data sources.

Edwards cited the example of a bank using SDO and SCA for an SOA rollout. Services were built with SCA, while IFX (Internal Financial Exchange) data was packaged with SDO, he said.

"Within the bank, they sold SCA as a way of enabling the business to build the services platform with very low barriers to adoption," Edwards said.

There are multiple implementations of SCO and SDO, said Edwards.

Reprinted with permission from

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