Databases Reference
In-Depth Information
A business fault, by our definition, is just another valid response that can be returned
by a component. Therefore, the role of the Mediator is to transform that fault from a
component-specific one to one defined in the WSDL of the composite service, which
it can then return to its client.
Its secondary role is to act as a proxy for the composite to any external service called
by a component within the composite. Here it is responsible for transforming the
outbound message into one expected by the external service and vice versa for the
response, which includes any business fault which might be returned.
The exact nature of how we handle a fault comes down to whether the Mediator
provides a synchronous or asynchronous service. We will examine each of
these cases.
Synchronous Mediators
With a synchronous Mediator, if we call a synchronous service that returns one or
more business faults, then the routing rule will contain a
Fault
section (circled in the
next screenshot), which allows us to map each business fault returned by the service
to one defined in the WSDL of the Mediator.
To define a fault routing, from the first drop-down list simply select from the
list of faults returned by the
invoked
operation, and then in the second drop-down
list select the fault that you want to map it to from the list of faults returned
by the Mediator.
