YADS Model Schema - XML Schema

This is the XML Schema for the YADS model. 


  <?xml version="1.0" encoding="UTF-8"?>
  <!--
  
    YADS - XSD
  
    This document describes YADS - A Description Service
    in a W3C XML Schema.
  
    ==
  
    // From RDF Schema for YADS

    Resource:     doi:1014/yads-schema-2002-04-03
    Comment:      RDF Schema for YADS - A Description Service
    Author:       Tony Hammond <tony_hammond@harcourt.com>
    Revision:     April 3, 2002 - Tony Hammond
  


  -->
  
  <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  
  <!--
    Toplevel wrapper element
    ~
  -->
  <xsd:element name = "yads">
    <xsd:simpleType>
      <xsd:choice>
        <xsd:element ref = "item" minOccurs = "0" maxOccurs = "unbounded"/>
        <xsd:element ref = "nest" minOccurs = "0" maxOccurs = "unbounded"/>
      </xsd:choice>
    </xsd:simpleType>
  </xsd:element>
  
  <!--
    Item element - collection OR resource, with properties.
    (The content model expressly permits any ordering.)
  -->
  <xsd:element name = "item">
    <xsd:complexType>
      <xsd:sequence>
        <xsd:choice>
          <xsd:element ref = "collection"/>
          <xsd:element ref = "resource"/>
        </xsd:choice>
        <xsd:element ref = "property" minOccurs = "0" maxOccurs = "unbounded"/>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>
  
  <!--
    Nest element - collection AND resource, with properties.
    (The content model expressly permits any ordering.)
  -->
  <xsd:element name = "nest">
    <xsd:complexType>
      <xsd:sequence>
        <xsd:choice>
          <xsd:complexType>
            <xsd:sequence>
                <xsd:element ref = "property"
                             minOccurs = "0" maxOccurs = "unbounded"/>
                <xsd:element ref = "collection"/>
                <xsd:element ref = "property"
                             minOccurs = "0" maxOccurs = "unbounded"/>
                <xsd:element ref = "resource"/>
                <xsd:element ref = "property"
                             minOccurs = "0" maxOccurs = "unbounded"/>
            </xsd:sequence>
          </xsd:complexType>
          <xsd:complexType>
            <xsd:sequence>
                <xsd:element ref = "property"
                             minOccurs = "0" maxOccurs = "unbounded"/>
                <xsd:element ref = "resource"/>
                <xsd:element ref = "property"
                             minOccurs = "0" maxOccurs = "unbounded"/>
                <xsd:element ref = "collection"/>
                <xsd:element ref = "property"
                             minOccurs = "0" maxOccurs = "unbounded"/>
            </xsd:sequence>
          </xsd:complexType>
        </xsd:choice>
      </xsd:sequence>
    </xsd:complexType>
  </xsd:element>
  
  <!--
    Collection element - contains sequence of nest or item elements.
    (An ordering attribute determines how the elements should be ordered.)
  -->
  <xsd:element name = "collection">
    <xsd:complexType>
      <xsd:attribute name = "order" default = "unordered">
        <xsd:simpleType>
          <xsd:restriction base = "xsd:NMTOKEN">
            <xsd:enumeration value = "unordered"/>
            <xsd:enumeration value = "sequenced"/>
            <xsd:enumeration value = "choice"/>
          </xsd:restriction>
        </xsd:simpleType>
      </xsd:attribute>
      <xsd:group>
        <xsd:choice>
          <xsd:element ref = "item" minOccurs="1" maxOccurs = "unbounded"/>
          <xsd:element ref = "nest" minOccurs="1" maxOccurs = "unbounded"/>
        </xsd:choice>
      </xsd:group>
    </xsd:complexType>
  </xsd:element>
  
  <!--
    Resource element
    ~
  -->
  <xsd:element name = "resource">
    <xsd:simpleType>
      <xsd:restriction base = "xsd:anyURI">
      </xsd:restriction>
    </xsd:simpleType>
  </xsd:element>
  
  <!--
    Property element
    ~
  -->
  <xsd:element name = "property">
    <xsd:complexType>
      <xsd:simpleContent>
        <xsd:restriction base = "xsd:string">
          <xsd:attribute name = "type" use = "required">
            <xsd:simpleType>
              <xsd:restriction base = "xsd:NMTOKEN">
                <xsd:enumeration value = "access"/>
                <xsd:enumeration value = "detail"/>
                <xsd:enumeration value = "directive"/>
                <xsd:enumeration value = "label"/>
                <xsd:enumeration value = "role"/>
                <xsd:enumeration value = "service"/>
                <xsd:enumeration value = "type"/>
              </xsd:restriction>
            </xsd:simpleType>
            </xsd:attribute>
        </xsd:restriction>
      </xsd:simpleContent>
    </xsd:complexType>
  </xsd:element>
  
  </xsd:schema>