W3C home > Mailing lists > Public > www-ws-desc@w3.org > June 2005

LC124: Ignore Unknowns, some proposed text

From: <paul.downey@bt.com>
Date: Wed, 15 Jun 2005 16:31:03 +0100
Message-ID: <2B7789AAED12954AAD214AEAC13ACCEF2709E40C@i2km02-ukbr.domain1.systemhost.net>
To: <jmarsh@microsoft.com>, <dorchard@bea.com>, <www-ws-desc@w3.org>

I think, as well as offering alternative syntax, Dave's proposal [1] is more tightly
coupled to Henry's technique than mine [2].  So although Dave may have
some different text in mind, here's my suggestion for the meaning 
of 'Ignore Unknowns'


[1] http://lists.w3.org/Archives/Public/www-ws-desc/2005Jun/0016.html
[2] http://lists.w3.org/Archives/Public/www-ws-desc/2005Jun/0012.html

The receiver of a message defined by an XML Schema 1.0 element marked
with an ignoreUnknows property of 'true' must ignore _unexpected items_
when processing the message.

Such additional, _unexpected items_ may be defined in a different 
version of the schema which may not be known or available to a 
sender, receiver or a third-party observing the message exchange, 
such as an XML Schema 1.0 validator.

_Unexpected items_ are attributes and elements not defined by the schema
for a particular element. _Unexpected items_ may appear in any namespace 
including the targetNamespace of a known schema, as well as in 
a namespace for which no schema is currently known. 

In the case of an unexpected element, it is the entire element tree, 
including any child elements, child attributes and content which 
must be ignored. 

Beofore checking the validity of a message contents against an XML Schema 
element marked with an ignoreUnknowns property value of 'true', any 
_unexpected items_should be first removed from the message.
How this removal should be achieved is undefined by this specification.

    Note: A number of different methods of identifying and removing
    _unexpected items_ exist. One such technique is to apply the XPath
    "*[pe:validity()='notKnown']" on the Post Schema Validation Infoset 
    (PSVI) produced as a result of XML Schema 1.0 validation. 
    For more information see [XML Schema: Structures] 
    and [some Appendix|Primer|Note|Whatever with a write up of 
    Henry's demo 
Received on Wednesday, 15 June 2005 15:31:08 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 21:54:54 UTC