The analysis and evaluation of design patterns for distributed real-time Java software

The real-time specification for Java (RTSJ) introduces a new memory model featuring some programming constraints that impede the "as-is" use of many well known design patterns. In this context, this paper describes and evaluates two design patterns, developed by the authors for distributed real-time Java software, that are able to overcome the limitations imposed by RTSJ. The first pattern, RTJ-leader-follower; is a RTSJ-compliant version of the well-known leader/follower pattern. The second pattern, called scoped tunnels, provides a new communication mechanism for RTSJ threads executing in different and incompatible memory areas, thus making possible the realization of the standard pattern half-sync/half-async for efficient network I/O handling. The paper presents both a qualitative and quantitative evaluation of these patterns, showing, above all, that they are able to provide a safe execution environment