T - The type of the requestpublic interface Provider<T>
Service endpoints may implement the Provider
  interface as a dynamic alternative to an SEI.
  
Implementations are required to support Provider<Source>,
  Provider<SOAPMessage> and
  Provider<DataSource>, depending on the binding
  in use and the service mode.
  
The ServiceMode annotation can be used to control whether
  the Provider instance will receive entire protocol messages
  or just message payloads.
Source, 
SOAPMessage, 
ServiceMode| Modifier and Type | Method and Description | 
|---|---|
| T | invoke(T request)Invokes an operation according to the contents of the request
  message. | 
T invoke(T request)
request - The request message or message payload.null if
              there is no response.WebServiceException - If there is an error processing request.
          The cause of the WebServiceException may be set to a subclass
          of ProtocolException to control the protocol level
          representation of the exception.MessageContext, 
ProtocolException