/*
* (c) Copyright 2006 Hewlett-Packard Development Company, LP
* All rights reserved.
* [See end of file]
*/
package squirrelrdf;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.hp.hpl.jena.query.DatasetFactory;
import com.hp.hpl.jena.query.Query;
import com.hp.hpl.jena.query.QueryFactory;
import com.hp.hpl.jena.query.ResultSet;
import com.hp.hpl.jena.query.ResultSetFormatter;
import com.hp.hpl.jena.query.engine1.QueryEngine;
import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.util.FileManager;
import com.hp.hpl.jena.vocabulary.RDF;
import com.hp.hpl.squirrelrdf.ldap.LdapMap;
import com.hp.hpl.squirrelrdf.ldap.LdapQueryEngine;
import com.hp.hpl.squirrelrdf.rdb.DbMap;
import com.hp.hpl.squirrelrdf.rdb.SQLQueryEngine;
/**
* A very simple servlet
*
* @author pldms
*
*/
public class Servlet extends HttpServlet
{
private static final long serialVersionUID = -5436891956454723505L;
final static Log log = LogFactory.getLog(Servlet.class);
final static int NONE = 0;
final static int RDB = 1;
final static int LDAP = 2;
Model config;
int type;
public void init()
{
String configFile = this.getInitParameter("config");
log.info("Config file: " + configFile);
config = FileManager.get().loadModel(
this.getServletContext().getRealPath(configFile));
if (config.contains(null, RDF.type, DbMap.Map))
type = RDB;
else if (config.contains(null, RDF.type, LdapMap.Map))
type = LDAP;
else
{
type = NONE;
throw new RuntimeException("Unknown configuration type");
}
}
public void doGet(HttpServletRequest req, HttpServletResponse resp)
{
doQuery(req, resp);
}
public void doPost(HttpServletRequest req, HttpServletResponse resp)
{
doQuery(req, resp);
}
public void doQuery(HttpServletRequest req, HttpServletResponse resp)
{
QueryEngine qe = null;
try
{
String theQuery = req.getParameter("query");
String stylesheet = tryParameter(req, "stylesheet", "xsl", "xslt",
"xslt-uri");
log.info("Query is:\n" + theQuery);
log.info("Stylesheet: " + stylesheet);
Query query = QueryFactory.create(theQuery);
if (type == LDAP)
qe = new LdapQueryEngine(query, config);
else
qe = new SQLQueryEngine(query, config);
qe.setDataset(DatasetFactory.create());
ResultSet results = qe.execSelect();
resp.setHeader("Content-Type", "application/xml");
ResultSetFormatter.outputAsXML(resp.getOutputStream(), results,
stylesheet);
}
catch (Throwable e)
{
log.error("Error: ", e);
resp.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
}
finally
{
if (qe != null)
qe.close();
}
}
/**
* Try to get a parameter with a variety of names
*
* @param req
* @param names
* @return null if not found, otherwise parameter value
*/
private String tryParameter(HttpServletRequest req, String... names)
{
for (String name : names)
{
if (req.getParameter(name) != null)
return req.getParameter(name);
}
return null;
}
}
/*
* (c) Copyright 2006 Hewlett-Packard Development Company, LP
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/