XML Schema Data Typing (cont.) - Page 11

Complex Types

Our final topic is the use of complex data types. For example, consider a home monitoring service that provides a concise update on your home. The data returned could include multiple data elements, such as the current temperature, security status, and whether the garage door is open or closed. Encoding this data into WSDL requires additional knowledge of XML Schemas, which reinforces the main precept that the more you know about XML Schemas, the better you will understand complex WSDL files.

To explore complex types, consider the WSDL file in Example 6-10. This WSDL file describes our Product Service from Chapter 5. The complex types are indicated in bold.

Example 6-10: ProductService.wsdl

<?xml version="1.0" encoding="UTF-8"?>
<definitions name="ProductService"
  targetNamespace="http://www.ecerami.com/wsdl/ProductService.wsdl"
  xmlns="http://schemas.xmlsoap.org/wsdl/"
  xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
  xmlns:tns="http://www.ecerami.com/wsdl/ProductService.wsdl"
  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
  xmlns:xsd1="http://www.ecerami.com/schema">
 
   <types>
     <xsd:schema
         targetNamespace="http://www.ecerami.com/schema"
         xmlns="http://www.w3.org/2001/XMLSchema">
         <xsd:complexType name="product">
            <xsd:sequence>
               <xsd:element name="name" type="xsd:string"/>
               <xsd:element name="description" type="xsd:string"/>
               <xsd:element name="price" type="xsd:double"/>
               <xsd:element name="SKU" type="xsd:string"/>
            </xsd:sequence>
         </xsd:complexType>
      </xsd:schema>
   </types>
 
   <message name="getProductRequest">
     <part name="sku" type="xsd:string"/>
   </message>
   
   <message name="getProductResponse">
     <part name="product" type="xsd1:product"/>
   </message>
 
   <portType name="Product_PortType">
     <operation name="getProduct">
       <input message="tns:getProductRequest"/>
       <output message="tns:getProductResponse"/>
     </operation>
   </portType>
 
   <binding name="Product_Binding" type="tns:Product_PortType">
     <soap:binding style="rpc"
         transport="http://schemas.xmlsoap.org/soap/http"/>
     <operation name="getProduct">
       <soap:operation soapAction="urn:examples:productservice"/>
       <input>
         <soap:body
             encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
             namespace="urn:examples:productservice"
             use="encoded"/>
       </input>
       <output>
         <soap:body
             encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
             namespace="urn:examples:productservice" use="encoded"/>
       </output>
     </operation>
   </binding>
 
   <service name="Product_Service">
     <port name="Product_Port" binding="tns:Product_Binding">
       <soap:address location=
	   		"http://localhost:8080/soap/servlet/rpcrouter"/>
     </port>
   </service>
</definitions>

The service in Example 6-10 describes a getProduct operation that returns a complex product type for encapsulating product information, including product name, description, price, and SKU number.

The new product type is defined in much the same manner as the array definition from the previous example. The main difference is that we are now using the sequence element. The sequence element specifies a list of subelements and requires that these elements appear in the order specified. XML Schemas also enable you to specify cardinality via the minOccurs and maxOccurs attributes. If these attributes are absent (as in our example), they default to 1, requiring that each subelement must occur exactly one time.

Each subelement can also have its own data type, and you can see that we have mixed and matched string data types with double data types in our example.

XML Schema Data Typing (cont.) - Page 10
Web Services Essentials
XML Schema Data Typing (cont.) - Page 12