Overview of the CORBA component model

The Common Object Request Broker Architecture (CORBA) object model is increasingly gaining acceptance as the industry standard, cross-platform, cross-language distributed object computing model. The recent addition of the CORBA Component Model (CCM) integrates a successful component programming model from EJB, while maintaining the interoperability and language-neutrality of CORBA. The CCM programming model is thus suitable for leveraging proven technologies and existing services to develop the next-generation of highly scalable distributed applications. However, the CCM specification is large and complex. Therefore, ORB providers have only started implementing the specification recently. As with first-generation CORBA implementations several years ago, it is still hard to evaluate the quality and performance of CCM implementations. Moreover, the interoperability of components and containers from different providers is not well understood yet. By the end of next year, we expect that CCM providers will implement the complete specification, as well as support value-added enhancements to their implementations, just as operating system and ORB providers have done historically. In particular, containers provided by the CCM component model implementation provide quality of service (QoS) capabilities for CCM components, and can be extended to provide more services to components to relieve components from implementing these functionalities in an ad-hoc way (Wang, 2000b). These container QoS extensions provide services that can monitor and control certain aspects of components behaviors that cross-cut different programming layers or require close interaction among components, containers, and operating systems. As CORBA and the CCM evolve, we expect some of these enhancements will be incorporated into the CCM specification.