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Subject: Re: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMSperMessage parameters
Marty:
Please see Bruce's explanation why it may still be useful to have negotiated
defaults for the AckRequested and DuplicateElimination parameters even when
the two parties have agreed that these be variable on a per message basis.
In my comments on the 1.09 draft, I am also questioning whether the
MessageOrder module needs to be treated similar to the AckRequested module
with "perMessage" semantics.
My assumption has been that Reliable Messaging (ack/timeout/retry) behavior
must be triggered by the presence of an Acknowledgment element in the
message. Either the application has to explicitly direct its local MSH to
construct an appropriate Acknowledgment element or the MSH must look up in
the CPA to determine if an Acknowledgment is to be created.
Similarly, whether duplicates are to be eliminated is controlled by the
duplicateElimination attribute within the QualityOfServiceInfo element.
Either the application has to explictly direct its local MSH to set this
attribute to the desired value or the MSH must consult the CPA for the
default value.
I am agreeable to simplifying the design to omit the recording of any
negotiated default from the CPA. In this case, whenever the CPA indicates a
parameter is "perMessage", the application must explicitly provide a value
for it so that the MSH can populatate the SOAP Header properly.
Regards,
-Arvola
-----Original Message-----
From: PEDRETTI,BRUCE (HP-NewJersey,ex2) <bruce_pedretti@hp.com>
To: 'Martin W Sachs' <mwsachs@us.ibm.com>
Cc: 'ebxml-msg@lists.oasis-open.org' <ebxml-msg@lists.oasis-open.org>
Date: Tuesday, November 27, 2001 8:28 AM
Subject: RE: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS
perMessage parameters
Marty,
I'm o.k. with requiring the attribute to be in the message header and also
happy with throwing an error if it is not. However, I think it is also ok
for the attribute to be absent *if* there is an *agreed on* default.
Even if we require the attribute's presence, there is the case where the
sending MSH has no indication from its app as to what value the attribute
should have. In that case, what value should it use? I don't think we can
assume that the business application will always know what value to use. Do
you? (If we can assume the business app always knows, then yes -- there is
no need for a default.)
Setting up a default value in the CPA eliminates the need for the sending
MSH to "second-guess" the two parties. Basically, the CPA is saying: "To
the sender MSH: if you do not know what to set this perMessage attribute to,
use 'x' because that is what we (the two parties) have agreed on as a
default".
This notion of a perMessage default is Arvola's embellishment on perMessage
semantics. I think it is a good and necessary one (based on the assumption
that the business app does not always know about this parameter or how to
set it). Admittedly, allowing a default value is not something that we have
formally agreed on as a group, that I know of. That said, I think it
logically follows the decisions that we have made.
Bruce
============================================
Bruce Pedretti Hewlett-Packard Company
Software Developer 6000 Irwin Road
(856) 638-6060 Mt. Laurel, NJ 08054
http://www.hp.com/
============================================
-----Original Message-----
From: Martin W Sachs [mailto:mwsachs@us.ibm.com]
Sent: Tuesday, November 27, 2001 10:52 AM
To: PEDRETTI,BRUCE (HP-NewJersey,ex2)
Cc: 'ebxml-msg@lists.oasis-open.org'
Subject: RE: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS
p erMessage parameters
Requiring that the attribute be in the message header simplifies things
considerably. There are only two possible values, so why allow the
attribute to be omitted from the message header? The attribute should be
required and an error thrown if it is missing. Certainly, guessing by the
MSH is totally off base. It can't be allowed to second-guess the two
parties.
Regards,
Marty
****************************************************************************
*********
Martin W. Sachs
IBM T. J. Watson Research Center
P. O. B. 704
Yorktown Hts, NY 10598
914-784-7287; IBM tie line 863-7287
Notes address: Martin W Sachs/Watson/IBM
Internet address: mwsachs @ us.ibm.com
****************************************************************************
*********
"PEDRETTI,BRUCE (HP-NewJersey,ex2)" <bruce_pedretti@hp.com> on 11/27/2001
10:15:43 AM
To: Martin W Sachs/Watson/IBM@IBMUS
cc: "'ebxml-msg@lists.oasis-open.org'" <ebxml-msg@lists.oasis-open.org>
Subject: RE: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS
p erMessage parameters
Marty,
Arvola needed to make this clear to me, as well. The use case is that two
partners agree to perMessage semantics. But in practice, what happens on
the sending MSH side when the business app makes no perMessage indication?
Should the sending MSH make a random choice? Or, what happens when the
receiving app gets a message that has no perMessage indication? What
should
the senders and receivers do in these cases? Establishment of an agreed
upon default value (other than the one in the cpa) would promote clear
expectations and consistent results.
Bruce
============================================
Bruce Pedretti Hewlett-Packard Company
Software Developer 6000 Irwin Road
(856) 638-6060 Mt. Laurel, NJ 08054
http://www.hp.com/
============================================
-----Original Message-----
From: Martin W Sachs [mailto:mwsachs@us.ibm.com]
Sent: Tuesday, November 27, 2001 9:22 AM
To: PEDRETTI,BRUCE (HP-NewJersey,ex2)
Cc: 'Arvola Chan'; ebxml-msg@lists.oasis-open.org
Subject: RE: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS
p erMessage parameters
Since there are really only 3 cases: yes in CPA, no in CPA, per message, I
don't understand the need for a default in the message specification.
Given that the only usable values in the message are yes and no, why
should the attribute be permitted to be left out?
Regards,
Marty
****************************************************************************
*********
Martin W. Sachs
IBM T. J. Watson Research Center
P. O. B. 704
Yorktown Hts, NY 10598
914-784-7287; IBM tie line 863-7287
Notes address: Martin W Sachs/Watson/IBM
Internet address: mwsachs @ us.ibm.com
****************************************************************************
*********
"PEDRETTI,BRUCE (HP-NewJersey,ex2)" <bruce_pedretti@hp.com> on 11/26/2001
06:07:05 PM
To: "'Arvola Chan'" <arvola@tibco.com>, ebxml-msg@lists.oasis-open.org
cc:
Subject: RE: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS
p erMessage parameters
Arvola,
Thank you for helping me understand the issues. This design is elegant in
that you nicely cover the gambit with two attributes, but perhaps it is
difficult to understand because the "flag" attribute is dual-purpose.
Sometimes "flag" provides a fixed value, sometimes it provides a default.
This makes me a bit uneasy for two reasons: 1) if a value is a default,
then for readability the attribute name ought to indicate such (for
example, "perMessageDefault"); and 2) without annotated documentation,
this "dual-purpose" concept can not be expressed in a schema.
There are at least two other alternatives:
1) <DuplicateElimination inForce="perMessage" perMessageDefault="false"/>
2) Use element presence for boolean conditions. For example:
a) if duplicate elimination false: <DuplicateElimination> absent
b) if duplicate elimination true: <DuplicationElimination> present
c) if duplicate elimination perMessage: <DuplicateElimination
perMessageDefault="true"/>
All 3 seem to me to have pros and cons. My preference is for alternative
(1). My fellow hp developers prefer alternative (2). If you go with your
original proposal, careful documentation may be important.
Bruce
============================================
Bruce Pedretti Hewlett-Packard Company
Software Developer 6000 Irwin Road
(856) 638-6060 Mt. Laurel, NJ 08054
http://www.hp.com/
============================================
-----Original Message-----
From: Arvola Chan [mailto:arvola@tibco.com]
Sent: Monday, November 26, 2001 4:24 PM
To: PEDRETTIBRUCE (HP-NewJerseyex2); ebxml-msg@lists.oasis-open.org;
ebxml-cppa@lists.oasis-open.org
Subject: Re: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS
permessage parameters
Bruce:
I was allowing for the fact that the two parties may have agreed that a
property like AckRequested is "perMessage" and still specify in the CPA a
bilaterally agreed default value (which can be different from the schema
default) for the property should the sending application omit to specify a
value for this property.
If such negotiated defaults are unnecessary, then I agree that your
suggested simplifications will be sufficient.
Thanks,
-Arvola
-----Original Message-----
From: PEDRETTI,BRUCE (HP-NewJersey,ex2) <bruce_pedretti@hp.com>
To: 'Arvola Chan' <arvola@tibco.com>; ebxml-msg@lists.oasis-open.org <
ebxml-msg@lists.oasis-open.org>
Date: Monday, November 26, 2001 12:36 PM
Subject: RE: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS
permessage parameters
<bp>Comments in-line...</bp>
-----Original Message-----
From: Arvola Chan [mailto:arvola@tibco.com]
Sent: Monday, November 26, 2001 2:58 PM
To: PEDRETTIBRUCE (HP-NewJerseyex2)
Cc: ebxml-msg@lists.oasis-open.org; ebxml-cppa@lists.oasis-open.org
Subject: Re: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS p
ermessage parameters
Bruce:
Please see my embedded comments.
Regards,
-Arvola
-----Original Message-----
From: PEDRETTI,BRUCE (HP-NewJersey,ex2) <bruce_pedretti@hp.com>
To: 'Arvola Chan' <arvola@tibco.com>
Cc: ebxml-msg@lists.oasis-open.org <ebxml-msg@lists.oasis-open.org>
Date: Monday, November 26, 2001 10:35 AM
Subject: RE: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS p
ermessage parameters
Arvola,
Thanks for taking the initiative to present these ideas to the cpa team.
Comments:
1) Personally speaking, I had envisioned an attribute for
DuplicateElimination that had the enumerated values: true, false,
perMessage. For example, <DuplicateElimination inForce="true"/> or
<DuplicateElimination inForce="perMessage"/>.
<ac>
Even when the two parties agree that duplicate elimination is to be
specified per message, the sending MSH may still want to look to the CPA
for guidance on how this attribute should be set. That is, the application
may explicitly specify a value for the duplicateElimination attribute, or
choose to omit it in which case the CPA should provide the default value.
Therefore, just having "perMessage", "true", and "false" as the only
possible values for the inForce attribute is not quite sufficient. <bp>I
don't understand what you mean by "not sufficient". What other possible
values might there be? Just to be explicit about the meaning of these
values as I see them:
1) If "true", then both parties agree that duplicateElimination is
inForce;
2) If "false", then both parties agree that duplicateElimination should
not be performed.
3) If "perMessage", then the Receiving MSH will comply with message header
(if possible).
Are there other arrangements? I agree that the CPA schema should provide
a default value, but that idea is not counter to an enumeration.</bp>
</ac>
2) The AckRequested issues could also be simplified with the same
enumeration. For example <Ack requested="true" signed="perMessage"/>.
<ac>
Similarly, the CPA should provide guidance to the sending MSH whether it
should construct an AckRequested element, if the application chooses to
omit such specification. <bp>Similar rebuttal as above</bp>
</ac>
3) Also, am I understanding correctly that you are proposing defaults for
AckRequested such that:
<AckRequested perMessageCharacteristics="perMessage"
includeInMessageHeader="false"/>
... are these default values at odds with each other? If AckRequested is
supposed to be decided on a per message basis, mustn't the info be
included in the message header -- or am I misunderstanding the
includeInMessageHeader attribute?
<ac>
The intended meaning is that the application may specify on a per message
basis, whether an AckRequested element should be constructed. However, if
the application omits such a specification, the MSH should not construct
an AckRequested element because includeInMessageHeader is set to false. At
the same time, this default can be changed by setting
includeInMessageHeader to true. <bp>Isn't an absence of AckRequested and
an AckRequested="false" semantic the same? Seems to me that if
the app says nothing about an MSH ack requested, then the MSH should not
create the AckRequested element. Under what circumstances might it need
to create an AckRequested="false"? </bp>
</ac>
-----Original Message-----
From: Arvola Chan [mailto:arvola@tibco.com]
Sent: Monday, November 19, 2001 7:16 PM
To: Doug Bunting
Cc: ebxml-msg@lists.oasis-open.org; ebxml-cppa@lists.oasis-open.org
Subject: Re: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS
per message parameters
Doug:
The first point in my original message was intended to differentiate
message properties that originate from BPSS from those that are specific
to the messaging specification. The DeliveryChannel element originally
contains a Characteristics element that carries BPSS related parameters. I
am recommending that Characteristics be renamed
BusinessProcessCharacteristics before we add the new
MessagingCharacteristics element.
Here is another suggested set of schema changes to address your desire to
allow
"acknowledgments are required for this delivery channel and the message
will indicate whether signing is required" or "any requested
acknowledgement must be signed".
<element name="MessagingCharacteristics">
<complexType>
<sequence>
<element ref="tns:AckRequested"/>
<element ref="tns:AckSignatureRequested"/>
<element ref="tns:DuplicateElimination"/>
</sequence>
</complexType>
</element>
<element name="AckRequested">
<complexType>
<attribute name="perMessageCharacteristics" type
="tns:perMessageCharacteristics.type" default="perMessage"/>
<attribute name="includeInMessageHeader" type="boolean" default
="false"/>
<attribute name="actor" type="tns:actor.type" default="toPartyMSH"/>
</complexType>
</element>
<element name="AckSignatureRequested">
<complexType>
<attribute name="perMessageCharacteristics" type
="tns:perMessageCharacteristics.type" default="perMessage"/>
<attribute name="flag" type="boolean" default="false"/>
</complexType>
</element>
<element name="DuplicateElimination">
<complexType>
<attribute name="perMessageCharacteristics" type
="tns:perMessageCharacteristics.type" default="perMessage"/>
<attribute name="flag" type="boolean" default="false"/>
</complexType>
</element>
<simpleType name="perMessageCharacteristics.type">
<restriction base="NMTOKEN">
<enumeration value="fixed"/>
<enumeration value="perMessage"/>
</restriction>
</simpleType>
<simpleType name="actor.type">
<restriction base="NMTOKEN">
<enumeration value="nextMSH"/>
<enumeration value="toPartyMSH"/>
</restriction>
</simpleType>
Regards,
-Arvola
-----Original Message-----
From: Doug Bunting <dougb62@yahoo.com>
To: Arvola Chan <arvola@tibco.com>
Date: Monday, November 19, 2001 3:26 PM
Subject: Re: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS
per message parameters
Arvola,
I'm not on the CPPA list and I'm unsure about the history here. Feel free
to forward your answers as appropriate.
What will the effect of the first point be? More particularly, what does
this have to do with the goals you've listed above?
The line "<attribute name="actor" type="tns:actor.type"/ default
="toPartyMSH">" needs the slash moved to the end.
I like what's been described as two separate Boolean values for
AckRequested in the CPA -- one that controls whether acknowledgements are
supported at all and another that controls whether any supported
acknowledgments may be signed. This proposal seems to eliminate that
separation. A CPA will not be able to say "acknowledgments are required
for this delivery channel and the message will indicate whether signing is
required" or "any requested acknowledgement must be signed".
thanx,
doug
----- Original Message -----
From: Arvola Chan
To: ebxml-cppa@lists.oasis-open.org ; ebxml-msg@lists.oasis-open.org
Sent: Monday, 19 November 2001 15:12
Subject: [ebxml-msg] Proposed CPP/A schema changes to deal with ebMS per
message parameters
At last week's ebxml-msg TC F2F meeting, it was agreed that the
duplicateElimination attribute (under QualityOfServiceInfo) and the
AckRequested element (under soap:Header)will in principle be treated as
parameters that are adjustible on a message by message basis. Trading
partners may specify in the CPA that they have agreed that these
parameters are variable per message, or that these parameters are to be
fixed at certain values, for a given delivery channel.
Accordingly, I am proposing the following changes/additions to the CPP/A
schema:
- Rename the existing Characteristics element under DeliveryChannel as
BusinessProcessCharacteristics.
- Add a MessagingCharacteristics element under DeliveryChannel.
- Add AckRequested and DuplicateElimination elements under the
MessagingCharacteristics element, as follows:
<element name="MessagingCharacteristics">
<complexType>
<sequence>
<element ref="tns:AckRequested"/>
<element ref="tns:DuplicateElimination"/>
</sequence>
</complexType>
</element>
<element name="AckRequested">
<complexType>
<attribute name="perMessageCharacteristics" type
="tns:perMessageCharacteristics.type" default="perMessage"/>
<attribute name="includeInMessageHeader" type="boolean" default
="false"/>
<attribute name="actor" type="tns:actor.type"/ default="toPartyMSH">
<attribute name="signed" type="boolean" default="false"/>
</complexType>
</element>
<element name="DuplicateElimination">
<complexType>
<attribute name="perMessageCharacteristics" type
="tns:perMessageCharacteristics.type" default="perMessage"/>
<attribute name="value" type="boolean" default="false"/>
</complexType>
</element>
<simpleType name="perMessageCharacteristics.type">
<restriction base="NMTOKEN">
<enumeration value="fixed"/>
<enumeration value="perMessage"/>
</restriction>
</simpleType>
<simpleType name="actor.type">
<restriction base="NMTOKEN">
<enumeration value="nextMSH"/>
<enumeration value="toPartyMSH"/>
</restriction>
</simpleType>
- If the perMessageCharacteristics attribute (under AckRequested and/or
DuplicateElimination) is 'perMessage', then both parties have agreed that
AckRequested and/or DuplicateElimination can be varied per message.
Furthermore, the sender would by default make use of attributes under the
AckRequested and DuplicateElimination elements within the CPA to populate
the AckRequested element and duplicateElimination attribute in the ebXML
message. For example, if the includeInMessageHeader attribute under
AckRequested is true, then an AckRequested element will be constructed
with its actor and signed attributes populated accordingly in the ebXML
message. Of course, the sender is free to populate the AckRequested
element in the ebXML message differently, based on other criteria (if the
CPA stipulates that this is to be treated as perMessage).
- Conversely, if the perMessageCharacteristics attribute is 'fixed', then
both parties have agreed that AckRequested and/or DuplicateElimination)
must always be set to the same values as indicated in the CPA under the
AckRequested and DuplicateElimination elements for the corresponding
DeliveryChannel. In this case, the sender is required to make use of
attributes under the AckRequested and DuplicateElimination elements within
the CPA to populate the AckRequested element and duplicateElimination
attribute in the ebXML message. For example, if the value attribute under
DuplicateElimination is true, then the duplicateElimination attribute
under QualityOfServiceInfo will be set to true. Any deviation from the
agreed upon fixed values would cause the receiver MSH to return an error.
Please let me know if you see a problem in the suggested schema change, or
if I have mis-represented the decision reached last Thursday.
Thanks,
-Arvola
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