/* ================================================================

  * Cewolf : Chart enabling Web Objects Framework

  * ================================================================

  *

  * Project Info:  http://cewolf.sourceforge.net

  * Project Lead:  Guido Laures (guido@laures.de);

  *

  * (C) Copyright 2002, by Guido Laures

  *

  * This library 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.

  *

  * This library 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., 59 Temple Place, Suite 330,

  * Boston, MA 02111-1307, USA.

  */

 package de.laures.cewolf.storage;

 import java.io.Serializable;

 import javax.servlet.ServletContext;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpSession;

 import javax.servlet.jsp.PageContext;

 import de.laures.cewolf.CewolfException;

 import de.laures.cewolf.ChartImage;

 import de.laures.cewolf.Storage;

 import de.laures.cewolf.taglib.util.KeyGenerator;

 /**

  * Storage stores images in session, but expires them after a certain time. 

  * This expiration time defaults to 300 seconds, and can be changed by adding 

  * the timeout="xxx" parameter to <cewolf:img> and <cewolf:legend> tags.

  * 

  * @author brianf

  */

 public class LongTermSessionStorage implements Storage

 {

   public final String getKey( ChartImage cid )

   {

     return String.valueOf(KeyGenerator.generateKey((Serializable) cid));

   }

   /*

    * (non-Javadoc)

    * 

    * @see de.laures.cewolf.Storage#storeChartImage(de.laures.cewolf.ChartImage,

    *      javax.servlet.jsp.PageContext)

    */

   public String storeChartImage( ChartImage chartImage, PageContext pageContext ) throws CewolfException

   {

     HttpSession session = pageContext.getSession();

     SessionStorageGroup ssg = (SessionStorageGroup) session.getAttribute("CewolfCharts");

     if ( ssg == null )

     {

       ssg = new SessionStorageGroup();

       session.setAttribute("CewolfCharts", ssg);

     }

     String cid = getKey(chartImage);

     SessionStorageItem ssi = new SessionStorageItem(chartImage, cid, chartImage.getTimeoutTime());

     ssg.put(cid, ssi);

     return cid;

   }

   /*

    * (non-Javadoc)

    * 

    * @see de.laures.cewolf.Storage#getChartImage(java.lang.String,

    *      javax.servlet.http.HttpServletRequest)

    */

   public ChartImage getChartImage( String id, HttpServletRequest request )

   {

     HttpSession session = request.getSession();

     ChartImage chart = null;

     SessionStorageGroup ssg = (SessionStorageGroup) session.getAttribute("CewolfCharts");

     if ( ssg != null )

     {

       SessionStorageItem ssi = (SessionStorageItem) ssg.get(id);

       if ( ssi != null )

       {

         chart = ssi.getChart();

       }

     }

     return chart;

   }

   /*

    * (non-Javadoc)

    * 

    * @see de.laures.cewolf.Storage#init(javax.servlet.ServletContext)

    */

   public void init( ServletContext servletContext ) throws CewolfException {

   }

   /**

    * @see de.laures.cewolf.Storage#removeChartImage(java.lang.String, javax.servlet.jsp.PageContext)

    */

   public String removeChartImage(String cid, HttpServletRequest request) throws CewolfException {

 	  HttpSession session = request.getSession();

 	  // No session exit

 	  if (session == null)

 	  {

 		  return cid;

 	  }

 	  SessionStorageGroup ssg = (SessionStorageGroup) session.getAttribute("CewolfCharts");

 	  if ( ssg == null )

 	  {

 		  // No group exit

 		  return cid;

 	  }

 	  ssg.remove(cid);

 	  return cid;  

   }

 }