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: JCA binding (and Assembly+Policy specs)

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 defining an appropriate 
element/attribute for binding.jca that would provide an indirection for 
reusable config info.

Thanks.

-Anish
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