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The <portType> element combines multiple message elements to form a complete one-way or round-trip operation.

For example, a <portType> can combine one request and one response message into a single request/response operation. This is most commonly used in SOAP services. A portType can define multiple operations.

Let us take a piece of code from the WSDL Example chapter −

<portType name = "Hello_PortType">
   <operation name = "sayHello">
      <input message = "tns:SayHelloRequest"/>
      <output message = "tns:SayHelloResponse"/>
   </operation>
</portType>

• The portType element defines a single operation, called sayHello.
• The operation consists of a single input message SayHelloRequest and an
• output message SayHelloResponse.

Patterns of Operation

WSDL supports four basic patterns of operation −

One-way

The service receives a message. The operation therefore has a single input element. The grammar for a one-way operation is −

<wsdl:definitions .... > 
   <wsdl:portType .... > *
      <wsdl:operation name = "nmtoken">
         <wsdl:input name = "nmtoken"? message = "qname"/>
      </wsdl:operation>
   </wsdl:portType >
</wsdl:definitions>

Request-response

The service receives a message and sends a response. The operation therefore has one input element, followed by one output element. To encapsulate errors, an optional fault element can also be specified. The grammar for a request-response operation is −

<wsdl:definitions .... >
   <wsdl:portType .... > *
      <wsdl:operation name = "nmtoken" parameterOrder = "nmtokens">
         <wsdl:input name = "nmtoken"? message = "qname"/>
         <wsdl:output name = "nmtoken"? message = "qname"/>
         <wsdl:fault name = "nmtoken" message = "qname"/>*
      </wsdl:operation>
   </wsdl:portType>
</wsdl:definitions>

Solicit-response

The service sends a message and receives a response. The operation therefore has one output element, followed by one input element. To encapsulate errors, an optional fault element can also be specified. The grammar for a solicit-response operation is −

<wsdl:definitions .... >
   <wsdl:portType .... > *
      <wsdl:operation name = "nmtoken" parameterOrder = "nmtokens">
         <wsdl:output name = "nmtoken"? message = "qname"/>
         <wsdl:input name = "nmtoken"? message = "qname"/>
         <wsdl:fault name = "nmtoken" message = "qname"/>*
      </wsdl:operation>
   </wsdl:portType >
</wsdl:definitions>

Notification

The service sends a message. The operation therefore has a single output element. Following is the grammar for a notification operation −

<wsdl:definitions .... >
   <wsdl:portType .... > *
      <wsdl:operation name = "nmtoken">
         <wsdl:output name = "nmtoken"? message = "qname"/>
      </wsdl:operation>
   </wsdl:portType>
</wsdl:definitions>