The Design and Implementation of Open ORB 2

Middleware has emerged as an important architectural component in modern distributed systems. However, it is now recognised that established middleware platforms such as CORBA and DCOM are not flexible enough to meet the needs of the emerging distributed applications, featuring for example access to multimedia services and also support for mobile users. Rather, we argue that next generation middleware platforms should be i) more configurable, ii) dynamically reconfigurable, and iii) should support the longer term evolution of the design of the platform. This paper discusses the design of the Open ORB v2 middleware platform, which addresses these requirements through an approach based on reflection together with the use of component technology. Important issues addressed in the paper include the use of architectural constraints to maintain the integrity of reflective middleware platforms, together with studies of efficient implementation of such technology. The capabilities of the Open ORB platform are also demonstrated through a series of application-level experiments.