The Exu approach to safe, transparent and lightweight interoperability

Exu is a new approach to automated support for safe, transparent and lightweight interoperability in multilanguage software systems. The approach is safe because it enforces appropriate type compatibility across language boundaries. It is transparent since it shields software developers from the details inherent in low-level language-based interoperability mechanisms, It is lightweight for developers because it eliminates tedious and error-prone coding (e.g., JNI) and lightweight at run-time since it does not unnecessarily incur the performance overhead of distributed, IDL-based approaches. The Exu approach exploits and extends the object-oriented concept of meta-object, encapsulating interoperability implementation in meta-classes so that developers can produce interoperating code by simply using meta-inheritance. In this paper, an example application of Exu to development of Java/C++ (i.e., multilanguage) programs illustrates the safety and transparency advantages of the approach. Comparing the performance of the Java/C++ programs produced by Exu to the same set of programs developed using IDL-based approaches provides preliminary evidence of the performance advantages of Exu.