A Metaobject Protocol for Fault-Tolerant CORBA Applications

The use of metalevel architectures for the implementation of fault-tolerant systems is today very appealing. Nevertheless, all existing fault-tolerant systems based on this approach have used a general-purpose metaobject protocol (MOP) or are based on restricted reflective features of some object-oriented language. According to our past experience in this field, we define in this paper a suitable metaobject protocol, called FTMOP, for the implementation of fault-tolerant metalevel architectures. The use of FT-MOP for building a faulttolerant system or for the implementation of fault tolerance strategies is left open to the system designer. We explain in this paper how to realize a specialized runtime MOP using compile-time reflection and describe FTMOP in details. Because of the unavoidable use of CORBA in distributed object systems and its interesting properties, this MOP is CORBA compliant: it enables the execution and the state evolution of CORBA objects to be controlled and enables the fault tolerance metalevel to be developed as CORBA software.