<xsd:schema 
    xmlns="http://www.ics.uci.edu/pub/arch/xArch/diff.xsd"
    xmlns:types="http://www.ics.uci.edu/pub/arch/xArch/types.xsd" 
    xmlns:archinstance="http://www.ics.uci.edu/pub/arch/xArch/instance.xsd" 
    xmlns:xlink="http://www.w3.org/1999/xlink" 
    xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
    targetNamespace="http://www.ics.uci.edu/pub/arch/xArch/diff.xsd"
    elementFormDefault="qualified"
    attributeFormDefault="qualified">

    <!-- Import namespaces used -->
    <xsd:import namespace="http://www.ics.uci.edu/pub/arch/xArch/instance.xsd"
                schemaLocation="http://www.isr.uci.edu/projects/xarchuci/core/instance.xsd"/>
    <xsd:import namespace="http://www.ics.uci.edu/pub/arch/xArch/types.xsd"
                schemaLocation="http://www.isr.uci.edu/projects/xarchuci/ext/types.xsd"/>
                
    <xsd:annotation>
      <xsd:documentation>
        xArch Diff XML Schema 1.0

        The following elements are used to define how to 
        represent a change between architectures.
        This schema can be used to show when an element 
        (connector, etc.) was removed or added to a 
        preexisting architecture.
      
        Depends on: {types.xsd, instance.xsd}

        Change Log:
           2002-07-23: Eric M. Dashofy [edashofy@ics.uci.edu]:
             Changed location of core (xArch) schema in the import
             statement to a more stable URL.
           2002-01-28: Eric M. Dashofy [edashofy@ics.uci.edu]:
            Upgraded to 2001 XML Schema standard and validated
             with XML Spy 4.2.  Only changes were to the namespace
             declaration for 'xsd' in the header.
           2001-04-12: Eric M. Dashofy [edashofy@ics.uci.edu]:
             Cleanup and validation by XML Spy 3.5.
           2001-04-09: Christopher van der Westhuizen [vanderwe@uci.edu]:
             Initial development and internal release.
      </xsd:documentation>
    </xsd:annotation>

    <!--
      Element: Diff
		
      The root element of any diff; it sits under the xArch element in an xArch
      document.
     -->
    <xsd:element name="diff" type="Diff"/>

    <!--
      TYPE: Add
		
      This element lists an addition to an architecture.  
      This would include the addition of a component, 
      connector, link, group, componentType, connectorType, 
      or an interfaceType.  The definition of the element 
      added is listed within the Add element.
     -->
    <xsd:complexType name="Add">
        <xsd:choice>
            <xsd:element name="component"     type="types:Component"/>
            <xsd:element name="connector"     type="types:Connector"/>
            <xsd:element name="link"          type="types:Link"/>
            <xsd:element name="group"         type="archinstance:Group"/>
            <xsd:element name="componentType" type="types:ComponentType"/>
            <xsd:element name="connectorType" type="types:ConnectorType"/>
            <xsd:element name="interfaceType" type="types:InterfaceType"/>
        </xsd:choice>
    </xsd:complexType>

    <!--
      TYPE: Remove
		
      This element indicates a removal of an element 
      from an architecture.  This includes the removal 
      of a component, connector, link, group, componentType, 
      connectorType, or an interfaceType.  The id of the 
      element to be removed is included in the remove element.
     -->
    <xsd:complexType name="Remove">
        <xsd:attribute name="removeId" type="archinstance:Identifier"/>
    </xsd:complexType>

    <!--
      TYPE: DiffPart
		
      This element contains either an add or a remove.
     -->
    <xsd:complexType name="DiffPart">
        <xsd:choice>
            <xsd:element name="add" type="Add"/>
            <xsd:element name="remove" type="Remove"/>
        </xsd:choice>
    </xsd:complexType>

    <!--
      TYPE: Diff
		
      This type describes the difference between one architecture 
      and another.  It describes what was removed and added by 
      means of a sequence of different diff elements each
      describing either a remove or an add.  By having a sequence 
      of diffParts it is possible to describe an unlimited 
      number of adds or removes in any specified order.
     -->
    <xsd:complexType name="Diff">
        <xsd:sequence>
            <xsd:element name="diffPart" type="DiffPart" 
                         minOccurs="0" maxOccurs="unbounded"/>
        </xsd:sequence>
    </xsd:complexType>
</xsd:schema>