Axis OWL-S Plugin uses the Axis Servlet Query String Plugin Mechanism. By evaluating query strings like ?wsdl
or
?owls
certain actions can be invoked. This is done by defining a Query String Plugin Handler.
The idea is, that such a Query string handler processes requests for OWL-S description for each Web service.
Currently it is planned to use the OWL-S API from the Mindswap project to generate descriptions in OWLS dynamically. Details about Mindswap and their OWL-S API can be found at the Mindswap OWL-S API Site.
Currently the OWLS plugin is realised on a basic level. OWL-S Descriptions are not created, but available in the file system.
To manage the description files a simple Web interface is provided.
It is possible to upload and name a OWLS file and to view all stored files.
If an OWLS description is requested by the query string ?owls
the handler looks for the appropriate file and returns it.
At the moment there is a problem with the Axis plugin mechanism. Although it is documented we didn't succeed to deploy our plugin in the descripted way. Axis (1.2 alpha, Java) doesn't seem to consider the server-config.wsdd
. As a temporary workaround we decided to define our Query String Handler as a default handler by editing the source of org.apache.axis.transport.http.AxisServlet
and rebuilding Axis. Following there are two ways to integrate the OWL-S Plugin:
server-config.wsdd
or
?owls
as default and thus modify the source code of the Axis servlet.
© 2004 Lars Engel and Michael C. Jaeger
Institut für Telekommunikationssysteme, FG IVS
Technische Universität Berlin