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Subject: RE: [sca-j] ISSUE 21 - Clarify Request Scope lifetime


Mike,

 

You are absolutely right.  The resolution was only w.r.t. java components.

 

Given that, I will agree with Dave B that in this case the conversation-propagation idea is a little bit different from request scope semantics.  Nonetheless, I think it would be close enough to warrant getting rid of the request scope.

 

Michael

 


From: Mike Edwards [mailto:mike_edwards@uk.ibm.com]
Sent: Thursday, March 13, 2008 10:44 AM
To: sca-j@lists.oasis-open.org
Subject: RE: [sca-j] ISSUE 21 - Clarify Request Scope lifetime

 


Folks,

Unless I've got the wrong end of the stick here, I think that the SCA Java TC is acting ultra vires.

Dave posed a question about a composite exposing two services, one conversational one non
conversational.

Michael responded saying that the Java F2F decided that a component cannot offer both a
conversational and non-conversational service.

Now, I can agree that the SCA Java TC decided that a Java implementation could not offer both a
conversational and a non-conversational service.  However, to extend this idea to apply to all
components, using whatever implementation type, I think must be a decision of the SCA Assembly
TC.

If the Java TC really wants to limit ALL components to only expose either conversational or non conversational
services, but never both, then I think the TC must get an appropriate issue raised in the Assembly TC. I suspect
that the other C&I TCs would need to be consulted also.


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


"Michael Rowley" <mrowley@bea.com>

13/03/2008 14:30

To

"David Booz" <booz@us.ibm.com>, <sca-j@lists.oasis-open.org>

cc

 

Subject

RE: [sca-j] ISSUE 21 - Clarify Request Scope lifetime

 

 

 





At the F2F we resolved that a component is not allowed to offer both a
conversational and non-conversational service.

Michael

-----Original Message-----
From: David Booz [mailto:booz@us.ibm.com]
Sent: Wednesday, March 12, 2008 10:35 PM
To: sca-j@lists.oasis-open.org
Subject: RE: [sca-j] ISSUE 21 - Clarify Request Scope lifetime

What if the composite exposes two services, one conversational and one
non-conversational?  Would the conversational service act as in 3 and
the
non-conversational service as in 4?  That's not clear from your text.
While it seems desireable to be able to answer yes to the second
question,
I'll observe that it means that components in that composite will run
differently (different context) depending on the inbound service.  This
is
another divergence from request scope.

...and while I have your attention...regrets for the call tomorrow.

Dave Booz
STSM, SCA and WebSphere Architecture
Co-Chair OASIS SCA-Policy TC
"Distributed objects first, then world hunger"
Poughkeepsie, NY (845)-435-6093  or  8-295-6093
e-mail:booz@us.ibm.com
http://washome.austin.ibm.com/xwiki/bin/view/SCA2Team/WebHome




            "Michael Rowley"

            <mrowley@bea.com>


To
            03/12/2008 10:14          "Barack, Ron"
<ron.barack@sap.com>,
            PM                        "OASIS Java"

                                      <sca-j@lists.oasis-open.org>


cc



Subject
                                      RE: [sca-j] ISSUE 21 - Clarify

                                      Request Scope lifetime


















During the F2F it was observed that the request scope is similar to the
conversation scope, except that it automatically propagates around the
local components of a composite.  Perhaps it would be simpler to take
advantage of this similarity and also expand on conversation scopes.  If
an
entire conversation can be marked as conversational, it could mean that
all
of the components within the composite work within the same
conversation.
This is also something that BEA has had customers ask for on its own
right.
However, if we did this, the request-scope could be removed, since
basically same semantics could be achieved by having a composite that
has
been marked as "local" be also marked as conversational.

The rules that we discussed at the F2F were:

1. Composite can be marked to propagate conversations through all
components within the composite ("propagatesConversation").
2. Request scope goes away.
3. If the composite service has a conversational interface, then if the
composite is marked as "propagatesConversation" then the conversation of
the composite's client will be propagated throughout all of the
components
within the composite.
4. If the composite service has a non-conversational interface, then if
the
composite is marked as "propagatesConversation", then (unless step 3
applies) a new conversation will be  started on each operation of the
composite service and propagated throughout the components within the
composite.
5. Marking a composite as "propagatesConversation" acts as if all the
components have been marked as "propagatesConversation".  Marking a
component with "propagatesConversation" means that any conversationID
passed into the component through a service will be passed with any call
on
a intra-composite wire from the component.

If this were to happen, it would probably have to be done in either the
policy or assembly TC.

Michael


     From: Barack, Ron [mailto:ron.barack@sap.com]
     Sent: Thursday, January 31, 2008 11:26 AM
     To: OASIS Java
     Subject: [sca-j] ISSUE 21 - Clarify Request Scope lifetime

     http://www.osoa.org/jira/browse/JAVA-21


     Von:: Michael Rowley [mailto:mrowley@bea.com]
     Gesendet: Montag, 21. Januar 2008 21:24
     An: OASIS Java.
     Betreff: [sca-j] NEW ISSUE: Clarify Request Scope lifetime

     RAISER: Michael Rowley

     TARGET: SCA Java Component Implementation Specification section
     titled "Request Scope"

     DESCRIPTION:

     The section currently starts with the following sentence:

     "The lifecycle of request scope extends from the point a request
on a
     remotable interface enters the SCA runtime and a thread processes
     that request until the thread completes synchronously processing
the
     request."

     From this description, it is not clear whether the request scope
     lasts through a remotable call to another component that happens
to
     be local.  In one possible interpretation it would depend on the
     binding.  A call through a web service binding would be seen as
     changing threads, and therefore would be a new request scope.  The
     same call through an SCA binding might be assumed to remain within
     the thread and therefore be within the same scope.

     It is probably a bad idea for the scope to depend on the binding
that
     is used, and it may even be a bad idea for the scope to depend on
     whether a call through a remotable interface _happens_ to be
local.

     PROPOSALS:

     1) Have the request scope be only for a single remotable operation
     call.  From that operation, any request scope component that is
     reached through only local-service calls would reach the same
     component instance.  Calls through a remotable interface would
     introduce a new request scope.

     2) Alternately, the request scope could last from the time a
request
     "enters the SCA runtime" until it is done, but with the
clarification
     that the "SCA Runtime" is domain-wide.  As long as a call is made
to
     another SCA component within the same domain (irrespective of the
     binding used) it is part of the same request scope.


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