Toward Automated Support for Transparent Interoperable Queries

Many object-oriented databases (OODBs) are based on programming languages (such as C++, CLOS and Smalltalk) that pre-date Java. Given Java’s rapid emergence, there is a growing need for interoperating existing or legacy OODBs with new applications that require Java. Unfortunately, there are few mechanisms that allow software developers to easily integrate Java applications with non-Java OODBs. Although various interoperability mechanisms have been developed, these approaches have some significant drawbacks in practice. They are often difficult to use, provide little, if any, automated support, and produce software that is difficult to engineer and maintain. In this paper, we describe ongoing work in providing interoperability support that allows application developers to seamlessly and transparently access non-Java OODBs from Java applications. Our approach involves embedding statements written in an object query language (called JOQL) into Java applications that are used to query C++-based OODBs. We also describe an accompanying toolset that processes Java programs containing JOQL queries. The toolset produces the necessary code allowing Java applications to access and manipulate a C++-based OODB. As a result, application developers are free to work in Java without having to concern themselves with the details of interoperating with C++. Finally, we provide some preliminary experimental data that demonstrates our approach incurs a modest performance overhead.