/*
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;

/**
* An abstract class defining the requirements for persisting
* session state across user transactions.  Used by WOApplication
* to persist sessions between requests.
*
* @author michael@mpowers.net
* @author $Author: cgruber $
* @version $Revision: 893 $
*/
public abstract class WOSessionStore
{
    private static WOSessionStore serverSessionStore = null;
    
    /**
    * Returns the default session store used by WOApplication.
    */ 
    public static WOSessionStore serverSessionStore()
    {
        if ( serverSessionStore == null )
        {
            serverSessionStore = new WOServletSessionStore();
        }
        return serverSessionStore;
    }

    /**
    * Called by WOApplication after the request-response cycle has ended.
    * The context's session will again be available for subsequent requests.
    */    
    public final void checkInSessionForContext(WOContext aContext)
    {
        saveSessionForContext( aContext );
    }
    
    /**
    * Returns the session with the specified id for the specified request,
    * or null if none exist.  Subsequent calls for the same id will return
    * null until the session is checked in again.
    * Called by WOApplication before the request-response cycle starts.
    */    
    public final WOSession checkOutSessionWithID(String sessionID, WORequest aRequest)
    {
        return restoreSessionWithID( sessionID, aRequest );
    }

    /**
    * Removes the WOSession for the specified ID from the store and returns it.
    */                                              
    public abstract WOSession removeSessionWithID(String sessionID);
    
    /**
    * Returns the WOSession for the specified ID from the store.
    */
    public abstract WOSession restoreSessionWithID(String sessionID,
                                                   WORequest aRequest);
                                                   
    /**
    * Places the context's session into the store.
    */
    public abstract void saveSessionForContext(WOContext context);
}

/*
 * $Log$
 * Revision 1.1  2006/02/16 13:22:22  cgruber
 * Check in all sources in eclipse-friendly maven-enabled packages.
 *
 * Revision 1.1  2003/01/07 20:48:29  mpowers
 * Implemented WOSessionStore and WOServletSessionStore.
 *
 *
 */