Integration of WWW Applications Based on Extensible XML Query and Processing Languages

Abstract

The rapid advance of the Internet has brought with it a variety of WWW applications. Integration of these WWW applications, which implies development of meta level applications (shortened to metaapplications), is an important research issue. In the Internet context, XML has attracted a great deal of attention and will be used as a standard data format in WWW applications. This paper proposes a scheme to develop meta-applications on top of XML-based WWW applications. Our approach uses an XML query language called X2QL to manipulate XML instances. X2QL features the inclusion of user-defined foreign functions so that we can define functions specific to WWW application integration, such as submitting forms and following hyperlinks. In addition, we propose X2PL, which is an extensible XML processing language. In X2PL, processing flows composed of embedded X2QL queries are specified. This paper also describes an integration example and the development of a prototype system.