Re: [ebxmlms-general] Sync messaging

[Ng C. Y. [Cyng] <cy...@cs...>]

Hello,

> I would like to know if there is any way to do synchronous messaging
> (sending and receiving of messages).
> I know that one way would be (on the receiving side), to implement the
> logic whic could ,based upon context(cpaid, service action), create
> apropriate message, open new connection and send the message back. But that
> doesn't complie to the specification where ot stands that the exchange of
> messages should by performerd on one connetion.

        You are right. In synchronous messaging using synchronous protocol
like HTTP, the sender of a message should receive the response message over
the SAME connection in which the request message is sent. This is stated
in Section 4.3 of ebMS 2.0.


> 2. What does happen if i implement MessageListener and my getClientURL
> method returns the URL of sender of received message. In body of onMessage
> method, i would then create appropriate message. Would this implementation
> return the message back to the sender and is this the right way to do sync
> messaging?

        Even you create appropriate message in onMessage(), the current
implementation would not send it back to the sender because onMessage() is
for receiving message only. You have to explicitly send your response message
through Request but this would not be sent synchronously through the same
HTTP channel in the current implementation.

> 3. How to synchronously SEND a message?

> 4.When can we excpect interfaces like public EbxmlMessage onMessage()  and
> public public EbxmlMessage mshReg.sendSync(...)

        To answer all these questions on SyncReply, we are now focusing on
the implementation. The mechanism is as follows. Upon construction, Request
is configured to indicate which SyncReply mode to use (which comes from CPA).
Then, MSH server would know that for the subsequent message sending and
receiving activities, it should keep the same HTTP connection for this
Request. This is totally transparent to the client of Request which makes
the client programming as easy as before.


> I also have another (a bitt out of context question)
> In TODO list for 0.9.3.1 version i found web-based client. I would like to
> know what do you mean by that.

        Oops, that is just an internal development tool for our developers.
It is not related to the release of Hermes.

> If i implement an servlet which sends messages and implements
> MessageListener I basicaly have a web client.

        Yes. This is one of the use cases of Hermes.

Regards,
CY

----------------------------------------------------------------------------
Ng Chi Yuen, CY.       cy...@ce...       http://www.cecid.hku.hk/
Technology Officer,
Centre for E-Commerce Infrastructure Development,
The University of Hong Kong
----------------------------------------------------------------------------