A Patterns Catalog for RTSJ Software Designs

In this survey paper, we bring together current progress to date in identifying Design Patterns[6] for use with the Real-time Specification for Java(RTSJ)[2] in a format consistent with contemporary Patterns descriptions. We begin by discussing some elementary patterns for structuring realtime applications. Specifically, we discuss the use of scoped memory for applications with periodic real-time behavior. We then discuss a simple extension to the factory pattern to accomodate memory areas. We survey existing work on scoped memory allocation[5] and recyclable immortal memory[4], and discuss some of the implications of such approaches for software design. Before describing the patterns in detail, we first define the following acronyms: RTT Real-time thread NHRTT: No-heap Real-time thread RTI: Real-time interval. Each cycle of a periodic thread occurs in the time span of one RTI.