com.bigdata.rdf.sail.webapp.RestApiGetContextsTask Maven / Gradle / Ivy

Go to download
/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016.  All rights reserved.

Contact:
     SYSTAP, LLC DBA Blazegraph
     2501 Calvert ST NW #106
     Washington, DC 20008
     [email protected]

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
package com.bigdata.rdf.sail.webapp;

import java.io.StringWriter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.openrdf.model.Resource;
import org.openrdf.repository.RepositoryResult;

import com.bigdata.rdf.sail.BigdataSailRepositoryConnection;
import com.bigdata.rdf.sail.webapp.XMLBuilder.Node;

/**
 * Task to report the contexts used by a QUADS mode KB instance.
 * 
 * @author Bryan Thompson
 */
class RestApiGetContextsTask extends AbstractRestApiTask {

   public RestApiGetContextsTask(final HttpServletRequest req,
         final HttpServletResponse resp, final String namespace,
         final long timestamp) {

      super(req, resp, namespace, timestamp);

   }

   @Override
   public boolean isReadOnly() {
      return true;
   }

   @Override
   public Void call() throws Exception {

      BigdataSailRepositoryConnection conn = null;
      try {

         conn = getQueryConnection();

         final StringWriter w = new StringWriter();

         final RepositoryResult it = conn.getContextIDs();

         try {

            final XMLBuilder t = new XMLBuilder(w);

            final Node root = t.root("contexts");

            while (it.hasNext()) {

               root.node("context").attr("uri", it.next()).close();

            }

            root.close();

         } finally {

            it.close();

         }

         buildResponse(QueryServlet.HTTP_OK, QueryServlet.MIME_APPLICATION_XML,
               w.toString());

         return null;

      } finally {

         if (conn != null) {

            conn.close();

         }

      }

   }

}