[oXygen-user] How Does Oxygen Validate This Dublin Core Schema?

[George Cristian Bina]

Hi Eliot,

I cannot reproduce the problem you have with Xerces 2.9.1. Neither from 
within oXygen nor from outside oXygen, running some of the Xerces 
samples from command line against the schema you provided and against 
dcterms.xsd.

It may be possible that you are using an old version of Xerces and not 
the latest 2.9.1?

Best Regards,
George
---------------------------------------------------------------------
George Cristian Bina - http://aboutxml.blogspot.com/
<oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
http://www.oxygenxml.com


Eliot Kimber wrote:
> In testing our own schema-based validation features in our RSuite 
> product we discovered that as far as we can tell Xerxes 2.9.x fails to 
> validate the valid Dublin Core schema given below. This is a documented 
> problem with Xerces in that it doesn't handle the particular pattern of 
> restriction and substitution groups used in this schema.
> 
> However, Oxygen happily (and correctly) validates documents using this 
> schema (that is, our test case fails when we parse it with our 
> Xerces-based code but Oxygen reports it as valid).
> 
> My understanding was that Oxygen used Xerces for its schema processing, 
> so my question is: what does Oxygen do special that allows it to process 
> this case, or is our understanding of Xerces flawed?
> 
> The failure we get is than an instance of e.g., dc:title is reported by 
> Xerces as not allowing character data content when of course it does.
> 
> The original discussion of this issue from the Dublin Core people is here:
> 
>   http://dublincore.org/schemas/xmls/qdc/2008/02/11/notes/
> 
> Very near the bottom is this:
> 
>     This derivation of a complexType with simpleContent by restriction 
> of a base complexType with complexContent is valid under section 3.4.6 
> of XML Schema Part 1: Structures, specifically item 5.1.2 of the section 
> "Schema Component Constraint: Derivation Valid (Restriction, Complex)", 
> because the base complexContent is mixed and emptiable.
> 
>     This was confirmed by Henry Thompson, see e.g.
>     http://www.w3.org/2001/05/xmlschema-rec-comments#pfiSimpleContent
>     http://lists.w3.org/Archives/Public/xmlschema-dev/2002Oct/0005.html
>     http://lists.w3.org/Archives/Public/xmlschema-dev/2002Oct/0008.html
> 
>     Conclusion: Xerces appears to be behaving incorrectly in rejecting 
> this derivation.
> 
> 
> Thanks,
> 
> Eliot
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
>            xmlns="http://purl.org/dc/elements/1.1/"
>            targetNamespace="http://purl.org/dc/elements/1.1/"
>            elementFormDefault="qualified"
>            attributeFormDefault="unqualified">
> 
>   <xs:annotation>
>     <xs:documentation xml:lang="en">
>       DCMES 1.1 XML Schema
>       XML Schema for http://purl.org/dc/elements/1.1/ namespace
> 
>       Created 2003-04-02
> 
>       Created by
> 
>       Tim Cole ()
>       Tom Habing ()
>       Jane Hunter ()
>       Pete Johnston (),
>       Carl Lagoze ()
> 
>       This schema declares XML elements for the 15 DC elements from the
>       http://purl.org/dc/elements/1.1/ namespace.
> 
>       It defines a complexType SimpleLiteral which permits mixed content
>       and makes the xml:lang attribute available. It disallows child 
> elements by
>       use of minOcccurs/maxOccurs.
> 
>       However, this complexType does permit the derivation of other 
> complexTypes
>       which would permit child elements.
> 
>       All elements are declared as substitutable for the abstract 
> element any,
>       which means that the default type for all elements is 
> dc:SimpleLiteral.
> 
>     </xs:documentation>
> 
>   </xs:annotation>
> 
> 
>   <xs:import namespace="http://www.w3.org/XML/1998/namespace"
>              schemaLocation="http://www.w3.org/2001/03/xml.xsd">
>   </xs:import>
> 
>   <xs:complexType name="SimpleLiteral">
>         <xs:annotation>
>         <xs:documentation xml:lang="en">
>             This is the default type for all of the DC elements.
>             It permits text content only with optional
>             xml:lang attribute.
>             Text is allowed because mixed="true", but sub-elements
>             are disallowed because minOccurs="0" and maxOccurs="0"
>             are on the xs:any tag.
> 
>             This complexType allows for restriction or extension permitting
>             child elements.
>         </xs:documentation>
>       </xs:annotation>
> 
>    <xs:complexContent mixed="true">
>     <xs:restriction base="xs:anyType">
>      <xs:sequence>
>       <xs:any processContents="lax" minOccurs="0" maxOccurs="0"/>
>      </xs:sequence>
>      <xs:attribute ref="xml:lang" use="optional"/>
>     </xs:restriction>
>    </xs:complexContent>
>   </xs:complexType>
> 
>   <xs:element name="any" type="SimpleLiteral" abstract="true"/>
> 
>   <xs:element name="title" substitutionGroup="any"/>
>   <xs:element name="creator" substitutionGroup="any"/>
>   <xs:element name="subject" substitutionGroup="any"/>
>   <xs:element name="description" substitutionGroup="any"/>
>   <xs:element name="publisher" substitutionGroup="any"/>
>   <xs:element name="contributor" substitutionGroup="any"/>
>   <xs:element name="date" substitutionGroup="any"/>
>   <xs:element name="type" substitutionGroup="any"/>
>   <xs:element name="format" substitutionGroup="any"/>
>   <xs:element name="identifier" substitutionGroup="any"/>
>   <xs:element name="source" substitutionGroup="any"/>
>   <xs:element name="language" substitutionGroup="any"/>
>   <xs:element name="relation" substitutionGroup="any"/>
>   <xs:element name="coverage" substitutionGroup="any"/>
>   <xs:element name="rights" substitutionGroup="any"/>
> 
>   <xs:group name="elementsGroup">
>       <xs:annotation>
>         <xs:documentation xml:lang="en">
>             This group is included as a convenience for schema authors
>             who need to refer to all the elements in the
>             http://purl.org/dc/elements/1.1/ namespace.
>         </xs:documentation>
>       </xs:annotation>
> 
>   <xs:sequence>
>     <xs:choice minOccurs="0" maxOccurs="unbounded">
>       <xs:element ref="any"/>
>     </xs:choice>
>     </xs:sequence>
>   </xs:group>
> 
>   <xs:complexType name="elementContainer">
>       <xs:annotation>
>         <xs:documentation xml:lang="en">
>             This complexType is included as a convenience for schema 
> authors who need to define a root
>             or container element for all of the DC elements.
>         </xs:documentation>
>       </xs:annotation>
> 
>     <xs:choice>
>       <xs:group ref="elementsGroup"/>
>     </xs:choice>
>   </xs:complexType>
> 
> 
> </xs:schema>
> 
>