An XML-based component model for wrapping legacy codes as Java/CORBA components

Techniques for wrapping an MPI-based molecular dynamics (MD) simulation code as Java/CORBA components, for use within a distributed component based problem solving environment (CB-PSE), is presented. The legacy code for simulating a Lennard-Jones fluid is first wrapped as a single CORBA object, followed by division of the code into computational sub-units, where each sub-unit is wrapped as a CORBA object containing MPI calls, and run on a cluster of workstations-enabling different MPI implementations to inter-operate. Each CORBA object is a component, with its interface and constrains defined in XML, which enables a user to search for components suitable to a particular application, enables a component to be configured when instantiated, enables each component to register with an event listener and facilitates the sharing of components between repositories. The application architecture and task graph are also described in XML. Using a Java implementation, users can submit simulation tasks through a Web based interface, without needing to know implementation details of the legacy code, or the exact interaction between sub-units within the code. We provide performance comparisons of wrapping the entire MD code as a single object, verses wrapping sub-units within it.