Java Apps - XQL language and a Persistent W3C-DOM

Date:      Mon, 29 Mar 1999 20:21:11 +0200
From:      Ingo Macherius <>
To:        XQL List <>
Subject:   ANNOUNCE: XQL processor in Java

GMD-IPSI is pleased to announce Java based implementations of the XQL language and a persistent W3C-DOM.

The GMD-IPSI XQL engine [1] is a Java based storage and query application for large XML documents. The functionality may be accessed via command line invocation or the Java API. The engine consists of two main parts:

  1. A persistent implementation of the W3C-DOM

  2. A full implementation of the XQL language

The XQL engine implements the W3C-QL '98 workshop paper syntax of XQL. It uses a novel indexing algorithm for XML (publication pending), which indexes the document while processing the first query. Subsequent queries to the same document are considerably accelerated.

The persistent DOM implements the W3C-DOM interfaces on indexed, binary XML files. Documents are parsed once and are stored in this form, accessible to DOM calls without the overhead of parsing them first. A cache architecture additionally increases performance. At this time only read access is possible, support of the full W3C-DOM API is work in progress.

The GMD-IPSI XQL engine was developed as a research project in GMD's XML competence center by Gerald Huck [2], with contributions by Ingo Macherius [3]. It is free for non-commercial use and evaluation, see the download page for details. For commercial requests contact the main author.


Ingo Macherius//Dolivostrasse 15//D-64293 Darmstadt//+49-6151-869-882
GMD-IPSI German National Research Center for Information Technology
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