Title: what attributes the correlation knows about incoming messages?
Hello
Kristofer,
a
simple example, where the part er link is not know, is the case where you have 2
Business Process, say "Purchasing" and "Inventory". Both have a partner
supplier, and the engine knows about lets say 10 suppliers. The scenario featres
an acknowledgment business message, which contains
<ack><messagetype>ORDER</messagetype><refnum>123</refnum></ack>
to acknowledge the receipt of an order with the number 123 and the same vor an
inventory message. If I now receive a message from an supplier on the business
signal port, I find 2 business process definitions receiving on that port type
and from one of the suppliers. Therefore the correlator is the only one who can
decide, if this was a message for the inventory or purchasing
process.
This
roblem is more common for reliable B2B messaging than Web services. We use our
engine for EDI scenarios, and here it is common to have hundreds of actual
endpoints (for example VAN mailboxes) behind the same port type, and more than
one process definition use this port type).
Mit freundlichen Grüßen
Bernd
Eckenfels
Chief Architect
--
SEEBURGER
AG - Edisonstr.1 , D-75015 Bretten, Germany
Fax: +49 (0)7252 96-2400 - Phone:
+49 (0)7252 96-1256
mailto: - http://www.seeburger.de
-----Original Message-----
From: Kristofer Agren
[mailto:]
Sent: Monday, April 19, 2004 11:26
PM
To: Eckenfels. Bernd; 'bpel implementation';
Subject: [wsbpel-dev] RE:
[wsbpel-implement] what attributes the correlation knows about incoming
messages?
Bernd,
In our case, we rely
on knowing the partner link and operation for an incoming message, and the
“normal” input to the engine consists of the partner link, operation and the
message itself. I do not really understand why the partner link is so hard to
discern, since when a BPEL process is deployed, the engine knows what partner
links, port types and, ultimately, ports that are used to realize the
operations of the process. In our case, the communications binding that is
constructed during deployment is responsible for creating a “static” route
between the actual port, regardless if it is a Web Service, .NET, JMS, EJB,
etc. binding, and the partner link/operation.
Regards,
Kristofer
From:
Eckenfels. Bernd [mailto:]
Sent: Monday, April 19, 2004 1:33
PM
To: bpel implementation;
Subject: [wsbpel-implement] what
attributes the correlation knows about incoming
messages?
Hello,
this is a question to
implementors, how they understood the specification:
if I asume a SOAP Servlet, which
will receive HTTP Calls with SOAP (maybe a Axis Srvice or something like
this), it receives a SOAP Call on a specified URL (ip, port, local part) to a
method and with a specific message type.
With those parameters, the servlet
can look up the operation and port type. (since those are not part of
the soap call)
It also has some information about
the called (ip, basic authentication, xml security, soap headers) and may be
able to lookup a implementation specific trading partner.
But, it has a hard time to
actually know about a partner link. In fact due to correlations it may not
even try to find out the partner link.
So I asume, that the normal
"input" to the correlation engine of a BPEL engine is the representation of
the call, the portType/operation, but not the partner link. This also means,
that the correlation must be able to find the input message across multiple
receives from different or the same process definitions (i.e. with different
partner links).
I
also guess, that most engines will support some policies for actually
restricting incoming messages to a subset of the receive activities, but thtat
does not affect the basic asumption, that the implementaiotn of a bpel engine
has to deal with events to a specified porttype/operation with unspecified
partner link.
Especially since in the incoming
case late binding is as common as in the outgoing case (partners and partner
links in process definitions are very often only "roles" in B2B
scenarios).
Mit freundlichen Grüßen
Bernd
Eckenfels
Chief
Architect
--
SEEBURGER AG - Edisonstr.1 , D-75015 Bretten, Germany
Fax: +49 (0)7252 96-2400
- Phone: +49 (0)7252 96-1256
mailto: -
http://www.seeburger.de
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