Monday, September 24, 2007

What views are necessary to represent a SOA?


Service-Oriented Architecture (SOA) is a system architecture in which a collection of loosely coupled services communicate with each other using standard interfaces and message-exchanging protocols. As an emerging technology in software development, SOA presents a new paradigm, and some authors affirms that it affects the entire software development cycle including analysis, specification, design, implementation, verification, validation, maintenance and evolution [see 1, 2 and 3].

In this context, we discussed about the paper "SOA Views: A Coherent View Model of the SOA in the Enterprise", published at IEEE International Conference on Services Computing in 2006. The authors, Ibrahim and Misic, proposed a set of nine views to represent an SOA-based architecture software: Business view, Interface view, Discovery view, Transformation view, Invocation view, Component view, Data view, Infrastructure view, and Test view.

In our discussion, the first question was: Do current approaches, such as RUP 4+1 Model View and ADD method by SEI, attend the particularities within context of SOA design?

We agree with some views and we considerate interesting within SOA approach, such as Interface view and Discovery view. The first describes the service contract, and the second provides the information necessary to discover, bind, and invoke the service.

Additionally, I agree with the paper about to have several views for SOA, because they can conduct the architects to construct a solution with the particularities of SOA and to address the quality attributes of this kind of enterprise system.

Finally, I think that misses in this paper the relation among the stakeholders and the quality attributes that each view can be address. Besides, the paper does not show how each view can be represented. For architects, it is important to have models in order to help the architects to design the solution for each view. One example of this, it is using the UML sequence diagram for Discovery view, showing how the consumer can find the services in the service registry.

2 comments:

Ednaldo said...

I think, this paper enumerates a large number of views. Maybe it would be more simple to adapt some of the found approaches and add specific views related with SOA. Mainly views that describe how to reuse the services published by a specific server.

Jose Jorge Dias said...

I agree with you about the paper enumarates a large number of views. But, It is interesting you have several optional views that helps to design the architecture. Mainly in SOA context. For example, which view in 4+1 approach, would you put informations about service discovery? Normally, you would have to crate an use case view and realize it in other 4 views. In this case, 4+1 becomes more harder than the paper approach.