The general variables concept: a simple step from single- to multi-user environment

When implementing multi-user cooperation systems in a networked virtual environment, synchronizing local representations of a shared virtual world has to be considered. It involves distributing and storing the data that represent users' activity in the virtual world. The authors propose a concept of general variables, which formalizes the task of distributing, journaling and locking the data in the client-server model. To verify the employability of the concept, we have implemented a Java bundle comprising a server and a client-side library. Four multi-user applications are presented to demonstrate that with the help of the bundle, a single-user application can be turned into a multi-user one with minimum effort.