NonStop SOAP for Java User's Manual

SOAP Deployment Descriptor
NonStop SOAP for Java User’s Manual—523860-001
4-8
Fault Handling
Fault Handling
Occasionally, an error occurs on the server side. It could be a bad service
implementation, a bad client request, or normal operating difficulties. The SOAP
specification provides for the communication of these errors through the transmittal of
a SOAP Fault body element within a SOAP Envelope. The SOAP server tries to
capture an error state and then construct a SOAP Fault message containing a base set
of information about the error. To augment the fault information for a particular service
or to perform one or more additional tasks when an error state arises, the SOAP server
provides a pluggable fault-handling mechanism into which one or more fault listeners
may be registered to process faults. (The pluggable fault-handling mechanism in
Apache SOAP works on the event/listener model.). There are two basic fault-handlers:
•
org.apache.soap.server.DOMFaultListener
•
org.apache.soap.server.ExceptionFaultListner
Both fault-handlers augment the SOAP Fault message with additional information
about the fault; the first by adding a DOM element representing the root exception
which occurred, and the second by wrapping the root exception in a parameter.
Registering Fault Handlers
Fault handlers are registered by including one or more <faultListener> elements within
the deployment descriptor of a service.
Creating New Fault Handlers
Writing a Java class which implements the
org.apache.soap.server.SOAPFaultListener interface can create a new fault
handler. The single method which one needs to implement, fault (), takes in a
SOAPFaultEvent. The SOAPFaultEvent wraps the SOAP Fault and SOAP Exception
objects that were created due to the error. Once the new fault-handler class is created,
it has to be registered, see Registering Fault Handlers
.