Research And Implementation Of An Distributed Event-Based Middleware

Distributed object technology is an object-oriented technology which is accompanied by the development of network. After the appearance of network, the client/server computing service paradigm was developed. But after the application scale is expanded from local network to internet, the limitation of client/server paradigm became more and more clear and the middleware emerged. Middleware is a common service located between operating systems and applications, which is used to is isolate the different network hardware platform and the heterogeneous network protocol and make the application run on different platform smoothly. With the further development of object-oriented technology, the distributed object technology appears. Traditional object technology provides good code reuse with the encapsulation, inheritance and polymorphism. But all the objects are in the same program and can not be known and used outside of the program. The distributed object middleware is to resolve this problem, which provides a command standard composition framework and make software from different vendors can access each other via different address space, network and operating system.To build large scale distributed system, the new middleware paradigm break through the limitation of traditional request/response middleware which is tight-coupling between components, lack of information filtering and support of peer to peer communication semantics.In this thesis, we describe the design and development a distributed event-based middleware. The middleware is on the top of type and attribute based publish/subscribe model and focus on type check depending event data and integration with program language by event inheritance. In dealing with the dynamic and large scale distributed environment, the middleware use peer to peer technology to manage overlay network of event broker automatically and realize flexible event distribution. The implementation of routing algorithm is based on distributed hash table and use rendezvous node to reduce the routing status in the system. The routing algorithm introduces fault tolerance to fix the broken event dissemination tree. All the above do not sacrifice performance which can be proven by the evaluation experiments.Event based middleware also provides security service. Security adds access control to the system according secure publish/subscribe model which supports fine-grained access control decisions so that separate trust domains can share the same overlay broker network.