Java Integration of XQuery - an Information Unit-Oriented Approach
bits - Büro für Informations-Technologie und Software GmbH
An infrastructure for integrating XQuery into Java systems is described. The infrastructure comprises a new API (XQJPLUS, built on the standard API XQJ) and a tool for Java code generation. The basic idea of the approach is to deliver query results not in terms of query result items, but in terms of “information units”, ready-to-use entities assembled from the result items. The assembly process is guided by control information embedded into the query result, so that the query controls exactly what will be delivered, and in which form. Information units can represent information in a great variety of forms, including many map types and custom objects. The information units produced by a query are collected into a special container ("info tray") which offers name-based, intuitive access to the units. The query-specific structure of an info tray may be formally defined by a tray schema from which an "info shape" can be generated, a Java class representing a specific kind of info tray and offering compiler checked data access. Info trays also support data integration, as their possibly very heterogeneous contents can be addressed in a uniform way, using path-like expressions.