Question regarding Composite granularity in SOA Suite

Question

I have a question about service granularity in a SOA Suite composite. In your experience, what is the best way to implement an Enterprise Business Service in SOA Suite?
Say I have a service interface/wsdl that looks something like:
Customer
+ getCustomer
+ createCustomer
+ updateCustomer
+ .....
Would the operations on the service be best implemented as BPEL processes each living in their own composite, or as multiple processes in one composite with a mediator(based on the ebs wsdl) in front of them? I'm also using OSB, so I could do the routing there to each of the separate composites if I break up the operations into a composite for each. But that seems like the amount of composites would become unmaintainably high.
If I use the mediator to expose the ebs wsdl, then I would just use OSB for virtualization, throttling, etc.
Not too sure which way to go with this design, but any experienced input is appreciated. I did notice that AIA implements each operation as a separate composite.
Thanks.

Answer 1

As per the AIA architecture we should use Mediator in EBS layer, because of below reasons.
1. OSB is not part of SOA until 11g,
2. You have to re write the code for exposing EBS in OSB Layer, thats a huge work.
Both Mediator and OSB does the same thing, ofcouse there are some differences
As per your design if you use OSB for virtualization, that is fine, but you will be having one more layer of virtualization before it hits the actual composites, which will definately hit the performance, extra care we need take for OSB layer.
In my current project, we tried both the approach that you wanted to try.
Approach 1 : Exposing EBS in OSB Layer.
Tried rewriting the EBS wsdl because the port information will not be available by default, without that we will not be able to create proxy services in OSB.
Then for how many wsdl files you will rewrite the code, then you need to update the MDS as well with those.
Did a small POC and then decided to go with as is. Probably we will have OSB layer in AIA 12 g
Approach 2 : We are using OSB wrapper for thirdparty web services and adapter services not the provider abcs services. I feel this is overhead.
Thanks,
Vijay