SessionDistributedDataFactory.java

/**
 *   GRANITE DATA SERVICES
 *   Copyright (C) 2006-2015 GRANITE DATA SERVICES S.A.S.
 *
 *   This file is part of the Granite Data Services Platform.
 *
 *   Granite Data Services is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Lesser General Public
 *   License as published by the Free Software Foundation; either
 *   version 2.1 of the License, or (at your option) any later version.
 *
 *   Granite Data Services 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 Lesser
 *   General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
 *   USA, or see <http://www.gnu.org/licenses/>.
 */
package org.granite.clustering;

import javax.servlet.http.HttpSession;

import org.granite.context.GraniteContext;
import org.granite.logging.Logger;
import org.granite.messaging.webapp.ServletGraniteContext;

/**
 * @author Franck WOLFF
 */
public class SessionDistributedDataFactory implements DistributedDataFactory {

	private static final Logger log = Logger.getLogger(SessionDistributedDataFactory.class);
	

	public DistributedData getInstance() {
		HttpSession session = null;
		GraniteContext context = GraniteContext.getCurrentInstance();
		if (context instanceof ServletGraniteContext)
			session = ((ServletGraniteContext)context).getSession(false);
		
		if (session == null) {
			log.debug("Could not get distributed data, no session or session expired");
			return null;
		}
		
		try {
			session.getAttribute("dummy_checkValid");
		}
		catch (IllegalStateException e) {
			// Session already invalidated
			return null;
		}
		
		return new SessionDistributedData(session);
	}
}