001    /**
002     *   GRANITE DATA SERVICES
003     *   Copyright (C) 2006-2013 GRANITE DATA SERVICES S.A.S.
004     *
005     *   This file is part of the Granite Data Services Platform.
006     *
007     *   Granite Data Services is free software; you can redistribute it and/or
008     *   modify it under the terms of the GNU Lesser General Public
009     *   License as published by the Free Software Foundation; either
010     *   version 2.1 of the License, or (at your option) any later version.
011     *
012     *   Granite Data Services is distributed in the hope that it will be useful,
013     *   but WITHOUT ANY WARRANTY; without even the implied warranty of
014     *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
015     *   General Public License for more details.
016     *
017     *   You should have received a copy of the GNU Lesser General Public
018     *   License along with this library; if not, write to the Free Software
019     *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
020     *   USA, or see <http://www.gnu.org/licenses/>.
021     */
022    package org.granite.clustering;
023    
024    import java.io.IOException;
025    
026    import javax.servlet.Filter;
027    import javax.servlet.FilterChain;
028    import javax.servlet.FilterConfig;
029    import javax.servlet.ServletException;
030    import javax.servlet.ServletRequest;
031    import javax.servlet.ServletResponse;
032    import javax.servlet.http.HttpServletRequest;
033    
034    /**
035     * This filter forces the creation of an HTTP session. Only useful in cluster
036     * environments when sticky-session is enabled, in order to ensure that a client
037     * will always use the same cluster node.
038     * 
039     * @author Franck WOLFF
040     */
041    public class CreateSessionFilter implements Filter {
042    
043            public void init(FilterConfig config) throws ServletException {
044            }
045    
046            public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
047                    ((HttpServletRequest)request).getSession(true);
048                    chain.doFilter(request, response);
049            }
050    
051            public void destroy() {
052            }
053    }