[ebxml-msg] Comments on 1.09 schema

Arvola,

 

The current schema has a few mismatches with the specification 
and inconsistencies between our extensions.  Some of these issues may need 
to be resolved through changes to the document instead.  I'll start by 
suggesting changes to the schema.

 

thanx,

    doug

 

Generally:

  
Push content of Error element and the optional xml:lang 
  attribute down into an optional list of Description elements.  
  Implemented in my list of changes.  As mentioned in my "first half" 
  comments, this might be overkill -- an optional Description would be 
  fine. 
  
Suggest we remove messageOrderSemantics attribute and require 
  SequenceNumber in MessageOrder.  I did not implement this 
  change in my list, just commented on the issues.

  
For future versioning capabilities, we should support wildcard element 
  content in every SOAP extension we define and in the "larger" repeating 
  elements within those elements.  About all I'd exempt is eb:PartyId since 
  that's very extensible already (name/value pairs).  Without this, we 
  don't support easy extensibility and will have to replace the schema for every 
  improvement made.  As I commented in my versioning note (http://lists.oasis-open.org/archives/ebxml-msg/200111/msg00274.html), 
  wildcard elements support vertical extensions and our own versioning pretty 
  well.
  
Including wildcard attributes in the Schema Instance 
  namespace on the Manifest and MessageHeader would seem to support adding 
  the xsi:schemaLocation attribute to those elements.  However, we've 
  defined 9 SOAP extensions and the other 7 don't allow these attributes.  
  The simplest thing would be to recommend use of xsi:schemaLocation only on the 
  parent soap:Envelope, soap:Header and soap:Body elements.  Next in 
  complication would be allowing xsi:schemaLocation only for all our extension 
  elements and documenting that option in the specification.  I'd prefer to 
  limit future extensibility to the wildcard elements we've already 
  documented and should add to a few more elements. 
  
A few more comments in the schema would help, especially ones 
  that tell readers where an element might appear in a SOAP instance. 
  
Attribute groups would make the schema much more 
  readable.  One that contains (optional) eb:id and eb:version would be 
  applicable for every SOAP extension we've defined.  Another that adds 
  (required) soap:mustUnderstand could be used in our soap:Header 
  elements.  Since soap:actor is only used in a limited selection, that 
  shouldn't be part of any group.  I haven't defined these groups in my 
  detailed changes below. 
  
You've defined defaults for the SOAP attributes that SOAP 
  requires to have values in the instance.  (SOAP processors are 
  not required to validate received documents prior to dispatch.)  At most, 
  what's currently defined as a default should be mentioned in schema 
  comments.  Better would be leaving it out entirely.

Line by line in draft-msg-header-04.xsd:

  
15 s/MANIFEST/MANIFEST, for use in soap:Body element/ 
  
24 d [Remove the two anyAttribute cases.] 
  
46 s/MESSAGEHEADER/MESSAGEHEADER, for use in soap:Header 
  element/ 
  
64 d [Remove the two anyAttribute cases.] 
  
93 s/default="false"/use="required"/ [This is presently an 
  optional attribute in an otherwise empty and optional element.  Other 
  option would be to require QoS in MH but that adds useless text to an 
  instance.] 
  
96 s/SYNC REPLY/SYNC REPLY, for use in soap:Header 
  element/ 
  
98 a

  
<sequence>

  
 <any namespace="##other" processContents="lax" 
  minOccurs="0" maxOccurs="unbounded"/>

  
</sequence>

  
102 
  s/default="urn:oasis:names:tc:ebxml-msg:actor:nextMSH"// 
  
105 s/MESSAGE ORDER/MESSAGE ORDER, for use in 
  soap:Header element/ 
  
109 a

  
<any namespace="##other" processContents="lax" 
  minOccurs="0" maxOccurs="unbounded"/>

  
114 s/default="NotGuaranteed"/default="Guaranteed"/ 
  [The unguaranteed use of a sequence number seems like a remote use case, 
  default to expected one.  I'd actually prefer to eliminate this attribute 
  and require the SequenceNumber element rather than complicate things with this 
  "require this element if this attribute is set this way".] 
  
120 s/name="type"/name="status"/ [big one!!] 
  
125 s/ACK REQUESTED/ACK REQUESTED, for use in 
  soap:Header element/ 
  
127 a

  
<sequence>

  
 <any namespace="##other" processContents="lax" 
  minOccurs="0" maxOccurs="unbounded"/>

  
</sequence>

  
131 s/default="urn:oasis:names:tc:ebxml-msg:actor:toPartyMSH"// 
  
132 s|/>|use="required"/>| [Tri-state Booleans (missing, true or 
  false) don't make sense within optional elements.  Specification doesn't 
  say anything about the cardinality of this attribute.  Let's make it 
  always present when the AckRequested element appears.] 
  
135 s/ACKNOWLEDGMENT/ACKNOWLEDGMENT, for use in soap:Header element/ 
  
142 a

  
<any namespace="##other" processContents="lax" minOccurs="0" 
  maxOccurs="unbounded"/>

  
147 s/default="urn:oasis:names:tc:ebxml-msg:actor:toPartyMSH"// 
  
150 s/ERROR LIST/ERROR LIST, for use in soap:Header element/ 
  
154 a

  
<any namespace="##other" processContents="lax" minOccurs="0" 
  maxOccurs="unbounded"/>

  
159 s/default="Warning"/use="required"/ [Should be consistent with 
  Error@severity and we document both attributes as having calculated values (no 
  defaulting).] 
  
[It's a larger change (and would change the specification) but I'd 
  like to remove the optional xml:lang attribute and make the contents a 
  sequence of Description elements and / or any elements.  Next three 
  changes are what that would look like:] 
  
164-165 d 
  
164 a

  
<complexType>
 <sequence>
    <element 
  ref="tns:Description" minOccurs="0" 
  maxOccurs="unbounded"/>
    <any 
  namespace="##other" processContents="lax" minOccurs="0" 
  maxOccurs="unbounded"/>
 </sequence>

  
170-172 d 
  
175 s/STATUS RESPONSE/STATUS RESPONSE, 
  for use in soap:Body element/ 
  
180 a

  
<any namespace="##other" 
  processContents="lax" minOccurs="0" 
maxOccurs="unbounded"/>

  
187 s/STATUS REQUEST/STATUS REQUEST, for 
  use in soap:Body element/ 
  
191 a

  
<any namespace="##other" 
  processContents="lax" minOccurs="0" 
maxOccurs="unbounded"/>

  
232 s/default="1.1"// [This attribute is 
  required wherever it's used.  Default is meaningless.]