
 
        Returns a Java reference to the servant which should be used for this 
 request. servant_preinvoke() is invoked by a local stub.
 If a ServantObject object is returned, then its servant field 
 has been set to an object of the expected type (Note: the object may 
 or may not be the actual servant instance). The local stub may cast 
 the servant field to the expected type, and then invoke the operation 
 directly. The ServantRequest object is valid for only one invocation, 
 and cannot be used for more than one invocation.
        
        
Returns:
    a ServantObject object.
 The method may return a null value if it does not wish to support 
 this optimization (e.g. due to security, transactions, etc). 
 The method must return null if the servant is not of the expected type. 
Parameters:
 - 
self - The object reference which delegated to this delegate.
 - 
operation - a string containing the operation name.
 The operation name corresponds to the operation name as it would be 
 encoded in a GIOP request.
 - 
expectedType - a Class object representing the expected type of the servant.
 The expected type is the Class object associated with the operations 
 class of the stub's interface (e.g. A stub for an interface Foo, 
 would pass the Class object for the FooOperations interface).