A common superclass for the transaction interceptors.
The only important method in this class is invokeNext which is incharge
of invoking the next interceptor and if an exception is thrown, it must
follow the rules in the EJB 2.0 specification section 18.3.
This Interceptor validates the incomming arguments and the return value of the call.
Here is the place where you want to make sure that local object don't pass through
the remote interface.