Java']Java-based query driven simulation environment

The concept of Web-based simulation can be finally realized using Java. We have used Java to create a powerful simulation modeling library which is based on the process interaction paradigm. Java threads make it easy for us to implement each process (or active entity) as a thread. Our library, JSIM, supports both simulation and animation thus rendering the model developer's job easier. An important component of our approach is that we integrate our Java Simulator with a Database Management System (DBMS). The conceptual basis for this integration is an environment based on Query Driven Simulation, which allows simulation analysts to study the performance of systems simply by querying a database. Simulation inputs and outputs are stored in databases, and simulation models can be launched as a part of query processing. This integration also resolves a security restriction problem which Java imposes. Most browsers (e.g., Netscape Navigator) restrict Java applets from writing into a file which may be necessary to make simulation results available to the user. Our approach bypasses this problem by writing into a database. Databases are much less of a security concern since they already have substantial authorization mechanisms.