[xsd-users] abstract and substitutionGroup

[Ray Lischner]

We are trying to use substitutionGroup and abstract types. Below is a simplified form of our schema:

<xsd:schema xmlns:xsd=http://www.w3.org/2001/XMLSchema xmlns:msg="msg" targetNamespace="msg" elementFormQualified="true">
  <xsd:complexType name="Base" abstract="true"/>
  <xsd:complexType name="Der1">
    <xsd:complexContent>
      <xsd:extension base="msg:Base">
        <xsd:sequence>
          <xsd:element name="i" type="xsd:int"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>
  <xsd:complexType name="Der2">
    <xsd:complexContent>
      <xsd:extension base="msg:Der1">
        <xsd:sequence>
          <xsd:element name="s" type="xsd:string"/>
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>
  <xsd:complexType name="Msg">
    <xsd:sequence>
      <xsd:element ref="msg:base"/>
    </xsd:sequence>
  </xsd:complexType>
  <xsd:element name="message" type="msg:Msg"/>
  <xsd:element name="base1" type="msg:Base"/>
  <xsd:element name="der1" type="msg:Der1" substitutionGroup="msg:base"/>
</xsd:schema>

A program constructs a Msg object as follows:

#include "schema.h"
int main()
{
   xml_schema::namespace_infomap ns;
   ns[""].name = "msg";
   msg::Der2 d(1, "str");
   msg::Msg m(d);
   msg::message(std::cout, m, ns);
}

The resulting document is:

<message xmlns="msg">
  <base xsi:type="Der2">
    <i>1</i>
    <s>str</s>
  </base>
</message>

The author of the schema claims that the abstract property should prevent the use of <base>, and therefore force the use of <der1>:

<message xmlns="msg">
  <der1 xsi:type="Der2">
    <i>1</i>
    <s>str</s>
  </der1>
</message>

The author of the schema therefore claims that Code Synthesis has a defect. I'm afraid this dispute exceeds my level of XML Schema subtlety. Can you offer any help or suggestions? Thank you.

Ray Lischner,
Senior Member of Technical Staff
133 National Business Pkwy, Ste 150     t. 443.539.3448
Annapolis Junction, MD 20701                c. 410.854.5170
rlischner at proteuseng.com                     f. 443.539.3370

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