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From Srinath Perera <hemap...@gmail.com>
Subject Re: [Axis2] Deploying MessageReceivers per Operation
Date Tue, 26 Apr 2005 04:00:36 GMT
Yes in theory AFAIK MessageReceiver per Operation (MEP) make sense. It
make writing a Web Service bit complex. But as users are reusing the 
in built MessageReceiver I think that is ok. So Deepal shall we move
the messageReceiver attribute to the Opeartion level rather than at
the service level?

Thanks
Srinath

On 4/26/05, Jaliya Ekanayake <jaliya@opensource.lk> wrote:
> Chathura Herath wrote:
> 
> >Hi Jaliya, Deepal, all
> >
> >Its exactly my point, the MessgeReceiver is per MEP not per operation as the heading
of this thread implies(nor its per service). MEP is a real pain and there is an unprecedented
need for properly handling it.
> >
> >You are right about there is a need of a MessageReciever per given MEP and the fact
that given service can have operations with different MEP can be resolved making sure we select
the right receiver in the Dispatch phase. Anyway we are doing it now but apparently we have
only the IN_OUT MEP Receiver and infact we are in the process of writing a general framework
for MEPs. I.e. Proper figuring out of MEP aware receives and MEP aware MEPContexts.
> >So we are converging I think....
> >
> >Btw any thought of my use case stated in the earlier mail. Restating.. If both the
ping operation and the echo operation requires to use the same transport (e.g. HTTP would
be a likely) due to some external constraint like RM, we ll have to get the engine to reuse
same transport for two or more different MEP.
> >
> >Is this a valid use case??
> >
> >Comments??
> >
> >Thanks,
> >Chathura
> >
> >________________________________________
> >From: Jaliya Ekanayake [mailto:jaliya@opensource.lk]
> >Sent: Thursday, April 21, 2005 5:22 PM
> >To: axis-dev@ws.apache.org
> >Subject: RE: [Axis2] Deploying MessageReceivers per Operation
> >
> >Hi Chathura, Deepal and All,
> >
> >I would like to pay your attention to the following class.
> >
> >public class MyService {
> >    public void ping(String pingStr){
> >        //Ping implementation
> >    }
> >
> >    public String echo(String echoStr){
> >       //Echo String implementatino
> >        return echoStr;
> >    }
> >}
> >
> >Now if we need to deploy this as a web service containing two operations (one with
IN-ONLY MEP and the other with IN-OUT MEP) we are in trouble if we just allow the user to
mention one message receiver per service.
> >
> >Further, I am referring to the following lines( in the Axis 1.2 JavaProvider)
> >
> >--------------------------------
> >
> >if (operation != null &&   operation.getMep() == OperationType.ONE_WAY) {
> >                msgContext.setResponseMessage(null);
> >            } else {
> >                Message        resMsg  = msgContext.getResponseMessage();
> >
> >-------------------------------
> >
> >Now in our MessageReceiver we don't need to check the operation type, since we have
some special MEP aware MessageReceivers. Only problem is that we may have many operations
in one service with different MEPs
> >
> >Comments?
> >
> >Thanks,
> >
> >Jaliya
> >
> >
> >________________________________________
> >From: Chathura Herath [mailto:chathura@opensource.lk]
> >Sent: Thursday, April 21, 2005 2:48 PM
> >To: axis-dev@ws.apache.org
> >Subject: RE: [Axis2] Deploying MessageReceivers per Operation
> >
> >Hi Jaliya, Deepal, all
> >
> >I think we haven't looked at the problem in the correct angle. MEP and Operation
have a one to many relation ship so it will not be right to say we let each operation have
its own message receiver, neither it is correct to say we should have a message receivers
per service because the MEP is defined per operation.
> >
> >Many Operation  use One MEP
> >
> >The problem that jaliya has pointed out is very valid and believe we need to give
proper attention. But we have missed out one salient point here. The original MEP was an IN_ONLY
MEP but since the operation requires secure conversation the security module need to send
out a message  and get a message back.
> >The point in that in this case the security module has created a new MEP(OUT_IN if
you consider this EPR to be a server or it's the client side of the IN_OUT MEP ) which is
orthogonal to the original MEP IN_ONLY. Further more now the endpoint has two parallel MEP's
running
> >1) Original IN_ONLY MEP :- This will have a receiver C a InOnlyReceiver
> >2) OUT_IN MEP created by the security module :- This will have its own receiver.
(Like a normal client)
> >
> >Now I believe there are no misunderstanding of having MessageReceivers because above
two message receivers will be provided and this operation and the security module can use
them. And any other service who has IN_ONLY MEP can use the above message receiver. Am I right?
> >
> >Complications come when you want to use the same transport to get everything done.
That we have to figure out a way to get the engine to reuse our old same transport.
> >
> >Comments?
> >
> >Cheers
> >Chathura
> >
> >
> >________________________________________
> >From: Deepal Jayasinghe [mailto:deepal@opensource.lk]
> >Sent: Thursday, April 21, 2005 10:30 AM
> >To: axis-dev@ws.apache.org
> >Subject: Re: [Axis2] Deploying MessageReceivers per Operation
> >
> >Hi Jaliya;
> >
> >I think we can handle operation basic receivers inside Message receiver , that is
because when some one implement a service he has to write a MessageReciver for his service
 , so inside the messagereciver he can write all the logic he needs to handle operation basis
reciever , that is inside messagereciver.recive() he can implement those logic.
> >
> >as an example
> >
> >MyReciver extends MessageReciver {
> >
> > public void recieve(MessageContext context){
> >    MyOperationReciever myop = new MyOperationReciever();
> >    myop.recieve(context);
> >  }
> >}
> >
> >
> >so if we do that in this way I think we do not need to define per operation basis
receivers.
> >
> >Comments ....
> >
> >Deepal
> >
> >Hi All,
> >
> >According the current implementation of Axis2, when we deploy a service, we can specify
one MessageReceiver (InOnlyMessageReceiver, InOutMessageReceiver etc..) per service. According
to my understanding we should let the user to register one MessageReceiver per operation basis.
Possible example would be as follows.
> >
> >We have a web service with IN-ONLY operation. However we need to let the service
to implement the RequestSecurityToken operation according to the WS-SecCon. This operation
is an IN-OUT operation. In this situation we have to register two message receivers to these
two operations. In addition, the MEP is bind to an operation and the MessageReceiver is the
one who is driving the MEP. So I think we have let each operation to have its own message
receiver.
> >
> >thoughts ??
> >
> >Thanks,
> >
> >Jaliya
> >
> >
> >
> >
> >
> >
> >
> Hi Chathura,
> 
> IMHO, there may not be a use case similar to what you have mentioned.
> There may be a case for one MEP to use the same transport or different
> transports, but not between MEPs
> 
> Thanks,
> 
> Jaliya
>
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