Object design of a distributed client/server system

This paper describes our practical experience in developing an object-oriented design and in implementing a prototype distributed client/server application. The system is described in terms of its individual components features and their interaction with other components via middleware. The prototype was coded in Java and employs two middleware technologies for clients/servers interaction. The main middleware employed is CORBA that has enabled us to achieve server location transparency by using CORBA's naming service. CORBA also provides a protocol to allow the communication between the components once binding between them occurred. The second middleware technology used was Java Database Connectivity (JDBC) which provided the means to query and maintain a distributed database. The features of JDBS and the way in which they were applied to the requirements of the application are also described. The prototype application was developed using Visigenic's VisiBroker and the generated classes were then extended using the Java SDK. The JDBC middleware layer was used to provide the link between the Java based servers and the databases. The main contribution of this work is mainly practical and is twofold. Firstly, we describe and share our experience in designing, implementing a prototype application using CORBA/JDBC, as well as our findings relating to performance aspects of the prototype. Secondly, and in the light of the results obtained, we evaluate our approach, lessons learned and suggest possible improvements and guidelines for developing similar systems and/or prototypes.