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Subject: RE: [sca-j] ISSUE 12: Relation between conversational annotation and scope conversation
- From: "Peshev, Peter" <peter.peshev@sap.com>
- To: "Simon Nash" <NASH@uk.ibm.com>, <sca-j@lists.oasis-open.org>
- Date: Thu, 7 Feb 2008 19:03:02 +0100
Hi Simon,
I am Ok with that suggestion.
I am just trying to clarify some parts of the spec
which are left not clearly stated.
NEW PROPOSAL :
It should be clarified that in the above example
-
Having a StatefullClass exposing service over a
non-conversational interface MUST generate an error at deployment.
The
instances of the class StatelessClass are NOT REQUIRED to
contain
conversational state between methods; Any instance can be used for
any client. An SCA runtime MAY provide a
pool of such objects and reuse them
among calling clients or MAY instantiate each time a new instance.
ConversationalId MUST be provided
since the interface was marked via
@Conversational
I'm OK with the second part of the
proposal, but not with the first part. When a conversation is initiated,
action is needed on the client side as well as the service side. If the
interface is not marked conversational, the client can't know that it should
perform the necessary actions. These include creating a conversation ID
and sending it on the wire.
I think
this combination of a non-conversational interface and a conversational
implementation should be treated as an error.
Simon
Simon C. Nash, IBM Distinguished Engineer
Member of the IBM
Academy of Technology
Tel. +44-1962-815156 Fax +44-1962-818999
"Peshev, Peter"
<peter.peshev@sap.com>
05/10/2007 09:20
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Subject
| RE: [sca-j] ISSUE 12: Relation
between conversational annotation and scope
conversation |
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Resending the email in this mail thread, just to keep track :
DESCRIPTION:
The annotation @Conversational is put on
interfaces, while the
annotation @Scope is put on the implementation types
for POJO-s. They
are used to control whether the runtime will keep
state or not between
invocations. (Some other future implementation
types in scope of the TC
may provide their own stateless and stateful
semantics equivalent to the
scope mechanics)
It should be clarified
what should happen if @Conversational is put on a
service interface however
the class which is exposing that service is
lacking @Scope(Conversation)
It should be clarified what should happen if there is NO
@Conversational
on a service interface however the class which is exposing
that service
is having @Scope(Conversation).
More precisely having
in mind the following definitions (each in its own
file) :
import
org.osoa.sca.annotations.Conversational;
@Conversational public interface
ConversationalInterface {}
---
public interface
NonConversationalInterface {public void test();}
---
import
org.osoa.sca.annotations.Scope;
import
org.osoa.sca.annotations.Service;
@Service(NonConversationalInterface.class)@Scope("CONVERSATION")
public
class StatefullClass implements NonConversationalInterface {
public void
test() {}}
---
import
org.osoa.sca.annotations.Service;
@Service(ConversationalInterface.class)
public
class StatelessClass implements ConversationalInterface{
public
void test() {}}
It
should be clraified whether it is legal to deploy such components and
what
should happen if a client calls via sca two times the method test()
for
ServiceReferences correspondant to the two classes. Is the
runtime
responsible to keep the state between the invocations
?
PROPOSAL :
It should be clarified that in the above example
-
Instances of the StatefullClass MUST contain conversational state
which
MUST be retained across methods and transactions called from the
client.
The instances of the class StatelessClass are NOT REQUIRED
to contain
conversational state between methods;
Any instance can be used
for any client. An SCA runtime MAY provide a
pool of such objects and reuse
them among calling clients or MAY
instantiate each time a new instance.
ConversationalId will be provided
since the interface was marked via
@Conversational
-----Original Message-----
From: Barack,
Ron [mailto:ron.barack@sap.com]
Sent: Thursday, 4. October 2007 21:07
To:
sca-j@lists.oasis-open.org
Subject: [sca-j] ISSUE 12: Relation between
conversational annotation and scope conversation
http://www.osoa.org/jira/browse/JAVA-12
-----Ursprüngliche
Nachricht-----
Von: Peshev, Peter [mailto:peter.peshev@sap.com]
Gesendet:
Donnerstag, 27. September 2007 17:48
An:
sca-j@lists.oasis-open.org
Betreff: [sca-j] NEW ISSUE: Relation between
conversational annotation and scope conversation
TARGET:
Java
Common Annotations and APIs specification
DESCRIPTION:
The
specification mentions @Conversational and @Scope(Conversation) but
there is
no clarification how these interfere together and what should
happen in all
the possible combinations.
PROPOSAL:
Two new paragraphs
should be added in section (3.2 @Conversational) that
have the following
wording :
In case an interface is marked as conversational but the
scope of the
target implementation is different than @Scope(Conversation),
than the
SCA runtime would invoke an instance as defined by the scope. In
case
the scope is the default one (stateless) than the container may
dispatch
to a new instance each time or alternatively pull one from a pool.
In
this case, it is assumed that the implementation itself will
manage
state. The implementation would be responsible for using
the
conversation id associated with the request (obtaining it
through
injection or via the SCA API) to obtain state stored somewhere (cache
,
database , etc.).
In case the target implementation has
@Scope(Conversation) and the
interface is NOT marked as conversational than
there will be no
conversation, attempts to retrieve conversationId will
result in null,
and the SCA runtime may behave as if for that particular
invocation the
scope has been defined as
stateless.
Unless stated otherwise above:
IBM United
Kingdom Limited - Registered in England and Wales with number 741598.
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6
3AU
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