To identify the information to provide in a SOAP fault at design time, you add fault elements to the operation response in a web service descriptor. The fault element, which is an IS document type, describes the expected structure of the Detail element in the SOAP fault. Fault elements are optional and can be added to any web service descriptor.

When you create a service first provider web service descriptor, add fault elements to represent the SOAP faults that an operation in the web service descriptor might return. If an error occurs at run time, the underlying service that corresponds to the operation can signal a fault by returning an instance document for one of the IS document types used as a fault element. Integration Server recognizes the fault document in the service pipeline and subsequently generates a SOAP response that contains a SOAP fault. Within the SOAP fault, the Detail element contains the fault document.

When you create a WSDL first provider web service descriptor or a consumer web service descriptor, Integration Server creates an IS document type for each message element in the source WSDL document. If an operation in a WSDL defines a soap:fault element, Integration Server generates an IS document type for the fault element.

In a consumer web service descriptor, the web service connector that corresponds to the operation includes logic to detect the fault element in the SOAP response. Integration Server then places the contents of the fault document into the detail document in the output parameter. The structure of the detail element matches the structure of the IS document type used as the fault element.

It is possible for a web service to return a fault that does not appear in a WSDL file. To account for these SOAP faults, you can add fault elements to a WSDL first provider web service descriptor or a consumer web service descriptor. For more information, see Adding a Fault Element to an Operation.