<xs:schema
    targetNamespace='http://www.w3.org/2009/02/ws-mex'
    xmlns:tns='http://www.w3.org/2009/02/ws-mex'
    xmlns:wsa10='http://www.w3.org/2005/08/addressing'
    xmlns:wsa04='http://schemas.xmlsoap.org/ws/2004/08/addressing'
    xmlns:xs='http://www.w3.org/2001/XMLSchema'
    elementFormDefault='qualified'
    blockDefault='#all' >

<!-- Get Metadata request -->
  <xs:element name='GetMetadata' >
    <xs:complexType>
      <xs:sequence>
        <xs:element ref='tns:Dialect' minOccurs='0' />
        <xs:element ref='tns:Identifier' minOccurs='0' />
      </xs:sequence>
      <xs:anyAttribute namespace='##other' processContents='lax' />
    </xs:complexType>
  </xs:element>

  <xs:element name='Dialect' type='xs:anyURI' />
  <xs:element name='Identifier' type='xs:anyURI' />

  <!-- Get Metadata response -->
  <xs:element name='Metadata' >
    <xs:complexType>
      <xs:sequence>
        <xs:element ref='tns:MetadataSection'
                    minOccurs='0'
                    maxOccurs='unbounded' />
        <xs:any namespace='##other' processContents='lax'
                minOccurs='0'
                maxOccurs='unbounded' />
      </xs:sequence>
      <xs:anyAttribute namespace='##other' processContents='lax' />
    </xs:complexType>
  </xs:element>

  <xs:element name='MetadataSection' >
    <xs:complexType>
      <xs:choice>
        <xs:any namespace='##other' processContents='lax' />
        <xs:element ref='tns:MetadataReference' />
        <xs:element ref='tns:Location' />
      </xs:choice>
      <xs:attribute name='Dialect' type='xs:anyURI' use='required' />
      <xs:attribute name='Identifier' type='xs:anyURI' />
      <xs:anyAttribute namespace='##other' processContents='lax' />
    </xs:complexType>
  </xs:element>

  <!--
       Ideally, the type of the MetadataReference would have been
       the union of wsa04:EndpointReferenceType and
       wsa10:EndpointReferenceType but unfortunately xs:union only
       works for simple types. As a result, we have to define
       the mex:MetadataReference using xs:any.
  -->

  <xs:element name='MetadataReference'>
    <xs:complexType>
      <xs:sequence>
        <xs:any minOccurs='1' maxOccurs='unbounded'
                processContents='lax' namespace='##other' />
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name='Location'
              type='xs:anyURI' />
</xs:schema>