A JAIN SLEE service may request that the SIS invoke an interceptor at any time during service execution.
Examples where this can be useful are in proxy or protocol translation services. The SIS already provides support for interceptors on the southbound dialog between the SIS and a service, but it does not impose any specific behaviours onto northbound dialogs created by a service. By coding a service to invoke SIS interceptors at points where messages are sent or received on a northbound dialog, it’s possible to provide pluggable, customisable behaviour without needing to recompile and redeploy the service.
|It’s possible for a SLEE service to invoke interceptor components in any SIS instance it has a resource adaptor entity binding to. However, interceptor script variables representing IN signaling parameters are only understood by the SIS for IN. Similarly, script variables representing SIP signaling parameters are only understood by the SIS for SIP. An interceptor that uses protocol-specific script variables therefore needs to be installed into an appropriate SIS instance in order for it to behave as expected when invoked by a service.
The following topics describe how interceptors can be invoked by a service and what the invocation result means: