Some questions on conversational interfaces and related intents

[Mike Edwards <mike_edwards@uk.ibm.com>]

Folks,

I am posting the following note to the
list on behalf of Vamsi, who is an IBMer and an observer on the TC and
who is in the
process of joining as a member:

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Assembly Model Specification - Section
1.5.3 on conversational interfaces lines 817 through 821:

817 This specification requires interfaces
to be marked as conversational by means of a policy intent
818 with the name "conversational".
The form of the marking of this intent depends on the
819 interface type. Note that it is
also possible for a service or a reference to set the conversational
820 intent when using an interface which
is not marked with the conversational intent. This can be
821 useful when reusing an existing
interface definition that does not contain SCA information.

If I have a java interface MyConvService
which is not annotated @Conversational, I will still be able to mark the
service as convesational by setting the intent as given in the following
xml fragment.
    <component name="MyConvServiceComponent">
        <implementation.java
class="org.apache.tuscany.sca.mytest.MyConvServiceImpl"/>
        <service
name="MyConvService" requires="sca:conversational">
         
  <interface.java interface="org.apache.tuscany.sca.mytest.MyConvService"
         
                  callbackInterface="org.apache.tuscany.sca.mytest.MyConvCallback"/>
         
  <binding.ws/>
         
  <callback>
         
      <binding.ws/>
         
  </callback>
        </service>
    </component>

Problem-1: Though it is possible to
add an "operation" element under "service", there does
not seem to be an intent using which the operation can be set as endsConversation.
 http://www.osoa.org/jira/browse/ASSEMBLY-47  seems to be related
to this to some extent, but proposes adding an "operation" element
inside the "interface" element.

Problem-2: The callback element seems
to inherit the conversational intent specified on the service.  But,
then it is not necessary that the callbackInterface for a conversational
service is also conversational.

Problem-3: Even if the callbackInterface
is conversational, there should be a way to set an endsConversation intent
on the callback's methods.  If the "operation" element under
"service" is to be used for this purpose, then we will need a
mechanism to identify whether the operation is from the service interface
or the callback.  The callback element does not seem to allow an operation
child element which may be used for this purpose.

Question: Suppose I have another component
which provides a service whose interface is also MyConvService
but does not set the conversational intent on the service, is it an error?

-------------------------------------



Yours,  Mike.

Strategist - Emerging Technologies, SCA & SDO.
Co Chair OASIS SCA Assembly TC.
IBM Hursley Park, Mail Point 146, Winchester, SO21 2JN, Great Britain.
Phone & FAX: +44-1962-818014    Mobile: +44-7802-467431  
Email:  mike_edwards@uk.ibm.com

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