Design Patterns and Component Framework for Building RTSJ-Based Real-Time Middleware

The middleware is a software layer located on top of the operating system that uses its facilities, integrates with it, and extends its functionality in order to support the development of effective and reliable distributed systems; however, the architectures of most of the conventional middleware solutions, e.g. Java RMI, do not either offer the predictability required to support the real-time behaviour in these systems, or the reconfigurablity required for these middleware solutions to be applicable in a wide range of distributed systems. Java has a great support for building distributed systems; however, due to its unpredictability, Java does not support building distributed real-time systems and middleware solutions. Hence, this thesis argues that the RTSJ can be used to build reusable and reconfigurable software components and design patterns that have high levels of predictability and reliability. These proposed real-time components and design patterns can be used for building real-time middleware solutions in Java. Therefore, the RTSJ has to be used as a base for modifying the existing reconfigurable and reusable software patterns and components for distribution models. It could also be used to create a new set of these patterns and components, in order to support the real-time behaviour and the predictability in the real-time middleware. The key contributions in this thesis include the presentation of a component framework design model for building RTSJ-based middleware and distributed systems; this framework focuses mainly on the memory model, the communication model of building the components and it also provides the management mechanism of these components, which uses a set of design patterns that integrates with these models. This includes a memory model for the RTSJ components associated with a set of reusability and life-management sub-components that support building real-time components in the RTSJ. Also, we provided a design of a real-time reconfigurable communication component based on the RTSJ that can be used to support predictable low level remote communications in distributed real-time Java applications and we showed how this component could be integrated within the component model as a sub-component, to provide communication services within the component model. Also, we presented our own model of integrating both the framework and the component model within the RMI architecture to provide a reconfigurable real-time Java RMI middleware based on the RTSJ.