NEW ISSUE: What is the purpose of definitions/binding element?

[Anish Karmarkar <Anish.Karmarkar@oracle.com>]

Title: What is the purpose of definitions/binding element?

Target: SCA policy spec (and SCA assembly spec/JCA binding)

Description:
The definitions infoset allows <bindingType> and <binding> child 
elements. It is quite easy to see how/why <bindingType> is used for. It 
points to the binding type (eg binding.ws) and specified which intents 
are always provided or can be provided.

But it is not clear what the definitions/binding element would be used 
for. In a composite/CT it is used to declare a binding instance that can 
contain a specific URL for the binding, policySets, etc. Neither the 
policy or the assembly spec explains what this element means when it 
occurs under definitions. AIUI (thanks Dave!), JCA binding uses it to 
specify common configuration information which is then referenced from a 
binding.jca instance. This, seems like a fine thing to do conceptually, 
but an unrestricted definitions/binding element should not be allowed. 
IOW, one should not be allowed to configure a definitions/binding.jca 
that contains a 'uri' attribute. Furthermore, you can't have, say, 
definitions/binding.ws, since it would be meaningless and very confusing.

I would like to point out that we have a similar requirement for 
properties and we use a 'file' attribute on component/property to 
satisfy that requirement. If this need is specific to JCA then I would 
suggest that the JCA binding should deal with this and not the 
policy/assembly specs.

Proposal:
If I got the usage right, then I would suggest getting rid of 
definitions/binding from Policy/Assembly and asking binding.jca to 
define an appropriate element/attribute that would provide an 
indirection for reusable config info.

Thanks.

-Anish
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