The path to loosely coupled.....  

I noticed a couple of interesting interviews on News.com this week that brought up several issues. The first was by Dave Hollander the CTO of Contivo titled Thinking about the future of data. He talks about schema and namespaces two key parts of the infrastructure that enable loosely coupled architectures. The other was an article by Gordon Van Huizen discussing RPC versus Messaging style semantics in SOAP Web services: Is it CORBA redux?. Reading the first interview one could assume that everything is going well as the industry is developing standards that will enable loosely coupled integration and services orientated architectures. The second makes clear that web services may be headed for a schism around RPC and messaging style interactions.

RPC programming models are very seductive, the concept of assembling applications from small distributed components is compelling but in general does not work. Exposing applications as RPC style interfaces does not promote integration and information sharing it has the opposite effect as it locks data into silos in a much tighter fashion. It also promotes brittle interfaces between applications causing the whole concept of loosely coupled architecture to break down and be replaced by brittle interfaces that lock applications tightly together.

This is not to say that RPC models do not have their place but in the larger context of SOA they are not the correct path to take.

posted by John McDowall | 1:02 PM