TheServerSide Java Symposium Europe – part 2

During The Server Side Java Symposium at Barcelona, one of the technologies that appeared with more future possibilities in SOA world is SCA, Service Component Architecture. I particularly liked the decoupling and composition of services approach.

In the conference Fabric 3, an Open Source SCA, was presented. Even though being a very young product, it looks very promising.

But, What is SCA? SCA is a way of building SOA services very decoupled. The following parts compose a SCA component:

• The business logic
• Configuration properties
• Exposed services: Operations that other clients can call
• References to other services (Dependencies)

One of the key things is that the transport used for the communications between services is not defined at compilation time. Instead, is configured at run time. This means that we can change, for example, from WS to JMS communication type without recompiling our code. This feature provides a lot of flexibility for complex production environments like banks.

Fabric 3 is a federated architecture for the provision of “service networks”. Instead of having a Enterprise Bus where all information communication is centralized in a single point (of course it can be clusterable ) this approach defines each component as an autonomous system that can communicate with other components directly.

Fabric 3 architecture is composed by several runtimes (App. Servers, Servlets Engines, OSGI Containers, etc) from different vendors and a small module attached for each of them. This small module allows that different runtimes acts as a “SCA runtime resource”. Furthermore, the architecture has a controller module that acts as a coordinator and deployment provider. When we deploy a new service to the SCA architecture, the SCA controller selects a valid “SCA runtime resource” for that service, and it deploys the new service there.

Personally I think that SCA is the distributing part that lacks OSGI. The combination of a OSGI runtime inside a SCA network could be a huge step in SOA architectures.

You can see the full presentation of Fabric 3 SCA at:
http://docs.codehaus.org/download/attachments/77960/TSSJS_2007.europe.final.pdf