This text file contains sample code fragments from:
Section 12.2 - Type Inheritance and Composition
Chapter 12 - Advanced XML Schema Part I: Message Flexibility, Type Inheritance, and Composition
Book - Web Service Contract Design & Versioning for SOA
Series - Prentice Hall Service-Oriented Computing Series from Thomas Erl
Site - www.soabooks.com


<xsd:complexType name="ProductType" abstract="true">
  <xsd:sequence>
    <xsd:element name="productID" type="ProductIDType"/>
    <xsd:element name="gtin" type="GTINType"/>
    <xsd:element name="title" type="TitleType"/>
    <xsd:element name="desc" type="xsd:string"/>
    <xsd:element name="msrPrice" type="PriceType"/>
    <xsd:element name="feature" maxOccurs="unbounded"
      type="FeatureType"/>
  </xsd:sequence>
</xsd:complexType>

Example 12.15 - A complexType element with an abstract attribute set to "true," thereby effectively establishing an abstract product type.


<xsd:element name="game" type="GameType"/>
<xsd:complexType name="GameType">
  <xsd:complexContent>
    <xsd:extension base="ProductType">
      <xsd:sequence>
        <xsd:element name="version" type="GameVersionType"/>
        <xsd:element name="onlinePreview" type="xsd:boolean"/>
      </xsd:sequence>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

Example 12.16 - The GameType complex type using the xsd:extension element to reference the ProductType complex type.


<game>
  <productID>AY2344</productID>
  <gtin>1234567890123</gtin>
  <title>Service Blaster 2000</title>
  <desc>This is a <i>great</i> game.</desc>
  <msrPrice>29.99</msrPrice>
  <feature name="hdtv">true</feature>
  <feature name="surround_sound">true</feature>
  <feature name="minPlayers">1</feature>
  <feature name="maxPlayers">3</feature>
  <feature name="esrbRating">EC</feature>
  <version>1.1</version>
  <onlinePreview>true</onlinePreview>
</game>

Example 12.17 - An instance of the GameType complex type. All highlighted parts are inherited.


<xsd:element name="console" type="ConsoleType"/>
<xsd:complexType name="ConsoleType">
  <xsd:complexContent>
    <xsd:extension base="ProductType">
      <xsd:sequence>
        <xsd:element name="version"
          type="ConsoleVersionType"/>
        <xsd:element name="colorChoices" type="xsd:string"/>
      </xsd:sequence>
    </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

Example 12.18 - The XML schema for the derived console type.


<xsd:schema ...>
  <xsd:group name="ProductProperties">
    <xsd:sequence>
      <xsd:element name="productID" type="ProductIDType"/>
      <xsd:element name="gtin" type="GTINType"/>
      <xsd:element name="title" type="TitleType"/>
      <xsd:element name="desc" type="xsd:string"/>
      <xsd:element name="msrPrice" type="PriceType"/>
      <xsd:element name="feature" maxOccurs="unbounded"
        type="FeatureType"/>
    </xsd:sequence>
  </xsd:group>
</xsd:schema>

Example 12.19 - An xsd:group is defined at the top level of the schema, as a child of xsd:schema.


<xsd:complexType name="GameType">
  <xsd:sequence>
    <xsd:group ref="ProductProperties"/>
    <xsd:element name="version" type="GameVersionType"/>
    <xsd:element name="onlinePreview" type="xsd:boolean"/>
  </xsd:sequence>
</xsd:complexType>

Example 12.20 - The GameType element pulls in the contents of the ProductProperties group via the use of the ref attribute of the group element.


<xsd:complexType name="ProductType">
  <xsd:sequence>
    <xsd:element name="productID" type="ProductIDType"/>
    <xsd:element name="gtin" type="GTINType"/>
    <xsd:element name="title" type="TitleType"/>
    <xsd:element name="desc" type="xsd:string"/>
    <xsd:element name="msrPrice" type="PriceType"/>
    <xsd:element name="feature" maxOccurs="unbounded"
      type="FeatureType"/>
  </xsd:sequence>
</xsd:complexType>
<xsd:complexType name="GameType">
  <xsd:sequence>
    <xsd:element name="productProperties" type="ProductType"/>
    <xsd:element name="version" type="GameVersionType"/>
    <xsd:element name="onlinePreview" type="xsd:boolean"/>
  </xsd:sequence>
</xsd:complexType>

Example 12.21 - A complex type that uses the GameType child element for composition.


<game>
  <productProperties>
    <productID>AY2344</productID>
    <gtin>1234567890123</gtin>
    <title>Service Blaster 2000</title>
    <desc>This is a <i>great</i> game.</desc>
    <msrPrice>29.99</msrPrice>
    <feature name="hdtv">true</feature>
    <feature name="surround_sound">true</feature>
    <feature name="minPlayers">1</feature>
    <feature name="maxPlayers">3</feature>
    <feature name="esrbRating">EC</feature>
  </productProperties>
  <version>1.1</version>
  <onlinePreview>true</onlinePreview>
</game>

Example 12.22 - An instance of a document based on the derived GameType complex type.