/*

  * Copyright (c) 2003-2011, Simon Brown

  * All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   - Redistributions of source code must retain the above copyright

  *     notice, this list of conditions and the following disclaimer.

  *

  *   - 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.

  *

  *   - Neither the name of Pebble nor the names of its contributors may

  *     be used to endorse or promote products derived from this software

  *     without specific prior written permission.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.

  */

 package net.sourceforge.pebble.web.servlet;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import javax.servlet.ServletException;

 import javax.servlet.http.HttpServlet;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import javax.servlet.http.HttpSession;

 import java.io.IOException;

 import java.util.Date;

 /**

  * Responds to HTTP pings, for keeping the session alive

  *

  * @author James Roper

  */

 public class PingServlet extends HttpServlet {

   private static final Log log = LogFactory.getLog(PingServlet.class);

   @Override

   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

     HttpSession session = req.getSession(false);

     if (session == null) {

       log.debug("Received ping with no session");

     } else {

       log.debug("Received ping from session " + session.getId());

     }

     resp.setContentType("text/plain");

     resp.getWriter().write("Pong response at " + new Date().toString());

   }

 }