/*

 Wotonomy: OpenStep design patterns for pure Java applications.

 Copyright (C) 2003 Intersect Software Corp.

 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, see http://www.gnu.org

 */

 package net.wotonomy.web;

 import java.io.ByteArrayInputStream;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.ObjectInputStream;

 import java.io.ObjectOutputStream;

 import java.io.ObjectStreamClass;

 import javax.servlet.http.HttpSession;

 /**

 * An implementation of WOSessionStore that stores WOSessions

 * inside of HttpSessions, to take advantage of the servlet 

 * containers built-in distribution capabilities.

 *

 * @author michael@mpowers.net

 * @author $Author: cgruber $

 * @version $Revision: 905 $

 */

 public class WOServletSessionStore extends WOSessionStore

 {

     private static final String ServletSessionKey = "WOServletSessionStoreKey";

     /**

     * This implementation currently does nothing and returns null, as we rely on the 

     * servlet container to dispose of the HttpSession which contains our WOSession.

     */                                              

     public WOSession removeSessionWithID(String sessionID)

     {

         return null;

     }

     /**

     * Returns the WOSession for the specified ID from the store.

     * The sessionID parameter is ignored, and the session is removed from

     * the store until saveSessionForContext is called.

     */

     public WOSession restoreSessionWithID(String sessionID, WORequest aRequest)

     {

         WOSession result = null;

         HttpSession servletSession = aRequest.servletRequest().getSession();

         if ( servletSession != null )

         {

             try

             {

                 result = (WOSession) servletSession.getAttribute( ServletSessionKey );

                 if ( result != null )

                 {

                     // if the servlet's class loader has changed, we need to reload

                     if ( result.getClass().getClassLoader() != 

                         WOApplication.application().getClass().getClassLoader() )

                     {

                         throw new ClassCastException( result.getClass().toString() );

                     }

                 }

             } 

             catch ( ClassCastException exc )

             {

                 // we're having an issue with the container's class loader:

                 // try serializing and deserializing to see if it is reloaded correctly

                 try

                 {

                     ByteArrayOutputStream bytes = new ByteArrayOutputStream();

                     ObjectOutputStream output = new ObjectOutputStream( bytes );

                     Object o = servletSession.getAttribute( ServletSessionKey );

                     output.writeObject( o );

                     output.flush();

                     output.close();

                     System.out.println( 

                         "WOServletSessionStore: reloaded session with size: " +

                         bytes.toByteArray().length );                

                     ObjectInputStream input = new CustomObjectInputStream( 

                         new ByteArrayInputStream( bytes.toByteArray() ),

                         WOApplication.application().getClass().getClassLoader() );

                     o = input.readObject();

                     input.close();

                     // try it again

                     result = (WOSession) o;

                 }

                 catch ( Exception e )

                 {

                     e.printStackTrace();

                     // give up: remove the attribute and allow a new session

                     servletSession.removeAttribute( ServletSessionKey );

                 }

             }

             if ( result != null ) 

             {

                 servletSession.removeAttribute( ServletSessionKey );

             }

         }

         //System.out.println( "restoreSessionWithID: " + sessionID + " : " + result );        

         return result;

     }

     /**

     * Places the context's session into the store.

     */

     public void saveSessionForContext(WOContext context)

     {

         //System.out.println( "saveSessionForContext: " + context + " : " + context.session() );        

         context.request().servletRequest().getSession( true ).setAttribute(

             ServletSessionKey, context.session() );

     }

     /**

     * Needed to specify a class loader which may be different that the

     * one used to load the ObjectInputStream class.

     */ 

     private static class CustomObjectInputStream extends ObjectInputStream

     {

         ClassLoader loader;

         public CustomObjectInputStream( 

             InputStream anInputStream, ClassLoader aClassLoader )

         throws java.io.IOException, java.io.StreamCorruptedException

         {

             super( anInputStream );

             loader = aClassLoader;

         }

         protected Class resolveClass(ObjectStreamClass v)

              throws IOException, ClassNotFoundException 

         {

             return loader.loadClass( v.getName() );

         }

     }

 }

 /*

  * $Log$

  * Revision 1.2  2006/02/19 01:44:02  cgruber

  * Add xmlrpc files

  * Remove jclark and replace with dom4j and javax.xml.sax stuff

  * Re-work dependencies and imports so it all compiles.

  *

  * Revision 1.1  2006/02/16 13:22:22  cgruber

  * Check in all sources in eclipse-friendly maven-enabled packages.

  *

  * Revision 1.7  2003/01/22 23:00:32  mpowers

  * Now keeping the most recent page around.

  *

  * Revision 1.6  2003/01/21 17:53:16  mpowers

  * Now handling reloading when wotonomy is on the system class path.

  *

  * Revision 1.5  2003/01/15 19:50:49  mpowers

  * Fixed issues with WOSession and Serializable.

  * Can now persist sessions between classloaders (hot swap of class impls).

  *

  * Revision 1.3  2003/01/14 16:05:19  mpowers

  * Removed extraneous printlns.

  *

  * Revision 1.2  2003/01/13 22:25:07  mpowers

  * Request-response cycle is working with session and page persistence.

  *

  * Revision 1.1  2003/01/07 20:48:24  mpowers

  * Implemented WOSessionStore and WOServletSessionStore.

  *

  *

  */