Here is the interface (followed by some other modification):
///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////
package org.apache.jserv;
import javax.servlet.http.*;
/**
* This is the object that encapsulates a session.
*
* @author Richard Bedard
* @version $Revision: 1.1.1.1 $ $Date: 2000/03/20 14:42:27 $
*/
public interface JServSessionStorage {
/**
* Called we we need to add a session object in our local table
* @PARAM session The session to keep
* @PARAM id The id of the session
*/
public void add(JServSession session, String id);
/**
* Called we we need to remove a session object of our local table
* @PARAM id The id of the session
*/
public void remove(String id);
/**
* Called when we need to update a session object in our local table
* @PARAM session The session to keep
* @PARAM id The id of the session
*/
public void update(JServSession session, String id);
/**
* Called to retrieve a session object
* Warning, never do intensive code here, this method can be called a
lot
* of time during a request
* @PARAM id The id of the session
*/
public JServSession get(String id);
/**
* Called when we need to load a session object in our local table,
called at
* the beginning of a request
* @PARAM id The id of the session
*/
public void load(String id);
/**
* Called we we need to create a session object of our own type
* @PARAM id The id of the session
* @PARAM context The context of the session (for base class
constructor)
* @RETURN session The session to keep
*/
public JServSession create(String id, JServServletManager context);
}
///////////////////////////////////////////////////////////////////////
/////// Member to add in JServServletManager
///////////////////////////////////////////////////////////////////////
/**
* Interface to implement to store or replicate session.
* By default no Storage is provided, its the user task to
* implement this interface.
*/
protected JServSessionStorage sessionStorage;
///////////////////////////////////////////////////////////////////////
/////// Add this in init (at the beginning) method of JServServletManager
///////////////////////////////////////////////////////////////////////
// Creation of the storage class
String sessionStorageClassName =
confs.getString("session.storage","none");
if (!sessionStorageClassName.equals("none"))
{
try{
sessionStorage =
(JServSessionStorage)Class.forName(sessionStorageClassName).newInstance();
}catch (Exception e){
JServ.log.log(CH_WARNING,"Error creating Sessin storage
class for servlet zone " + name + " : " + e.toString());
}
}
///////////////////////////////////////////////////////////////////////
/////// Change the creation of the default hashtable (At the end of init
method)
///////////////////////////////////////////////////////////////////////
if (sessionStorage == null)
sessions = new Hashtable();
//// And only start the house keeping if we manage session localy
// Start housekeeping thread
// If we dont use JServ Session manager, then its not our job
// to validate session
if (sessions != null)
{
Thread housekeeping = new Thread(this);
housekeeping.setDaemon(true);
housekeeping.start();
}
///////////////////////////////////////////////////////////////////////
/////// The modified getSession method of JServServletManager
///////////////////////////////////////////////////////////////////////
/**
* Returns the session bound to the specified session ID.
*
* @param sessionID the ID of a particular session object.
* @return the session name. Returns null if the session ID does not
refer
* to a valid session.
*/
public synchronized HttpSession getSession(String sessionId)
{
HttpSession out = null;
// First check the local list
if (sessions != null)
out = (HttpSession) sessions.get(sessionId);
// If we dont find the session, then try the Storage List
if (sessionStorage != null && out==null)
{
out = sessionStorage.get(sessionId);
if (out != null)
((JServSession)out).setSessionContext(this);
}
return out;
}
///////////////////////////////////////////////////////////////////////
/////// The modified createSession method of JServServletManager
///////////////////////////////////////////////////////////////////////
/**
* Creates a new session.
*
* @param response The response used to send a cookie to the client.
* @param route Label to append to the id sent from jserv client.
* @return A new session.
*/
public synchronized JServSession createSession(HttpServletResponse
response, String route) {
JServSession s = null;
// Try to use our own implementation
if (sessionStorage != null)
s = sessionStorage.create(getIdentifier(route), this);
// use default implementation..
if (s == null)
s = new JServSession(getIdentifier(route), this);
if (this.sessionUseCookies) {
Cookie c = new Cookie(session_identifier, s.id);
// Removed to ....;
c.setPath("/");
response.addCookie(c);
}
if (sessions != null)
sessions.put(s.id, s);
if (sessionStorage != null)
sessionStorage.add(s, s.id);
if (!JServ.TURBO && JServ.log.active)
JServ.log.log(CH_DEBUG, "Created session: " + s.id);
return s;
}
///////////////////////////////////////////////////////////////////////
/////// The modified removeSession method of JServServletManager
///////////////////////////////////////////////////////////////////////
/**
* Remove a session from the context. This is called by the session
* when it is invalidated.
*
* @param s The session to remove from this context.
*/
public synchronized void removeSession(JServSession s) {
if (sessions != null)
sessions.remove(s.id);
if (sessionStorage != null)
sessionStorage.remove(s.id);
}
///////////////////////////////////////////////////////////////////////
/////// Two new method to add in JServServletManager
///////////////////////////////////////////////////////////////////////
/**
* Update a session. This is called after a request.
*
* @param s The session to update.
*/
public synchronized void updateSession(JServSession s) {
if (sessionStorage != null)
sessionStorage.update(s, s.id);
}
/**
* Force the manager to load a session.
* To be called before the servlet is execute.
*
* @param s The session to update.
*/
public synchronized void loadSession(String id) {
if (sessionStorage != null)
sessionStorage.load(id);
}
///////////////////////////////////////////////////////////////////////
/////// Add this in the finnaly of processRequest method of JServConnection
///////////////////////////////////////////////////////////////////////
// Update the session
if (session != null)
{
mgr.updateSession(session);
session.unlock();
}
///////////////////////////////////////////////////////////////////////
/////// And this before "JServSession s = (JServSession)
mgr.getSession(requestedSessionId);"
/////// of the processRequest method of JServConnection
///////////////////////////////////////////////////////////////////////
//Force the manager to load the session object
mgr.loadSession(requestedSessionId);
///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////
Richard B�dard
Software Developer
recruitsoft.com
390, Saint-Vallier est
Bureau 401
Qu�bec (Qu�bec)
Canada G1K 3P6
Yahoo fax/voice-mail: 1-507-262-1145
-----Original Message-----
From: sudhi [mailto:[EMAIL PROTECTED]]
Sent: 17 avril, 2000 13:20
To: Java Apache
Subject: Re: Session Fail over/Migration
Thanks Richard,
Thats what I was thinking. But we dont have that much time to implement
this logic. what I was looking was any example or code, so that we can
use it right away.
Thanks
Sudhi
Richard Bedard wrote:
>
> To solve this problem, i have modified some jserv class. I had an
interface
> with 3 method getSession, setSession and createSession. In
jserv.properties,
> i had a parameters that contains the user implementation of the interface,
> the object is then used instead of the Jserv session hashtable, in the
> implementation we use RMI to store Session Object in a global container,
> with this we have FULL fault tolerance. If you servlet crash in the middle
> of the execution, mod_jserv re-dispatch the call to another jserv, so the
> user never have error!
>
> Richard B�dard
> Software Developer
> recruitsoft.com
> 390, Saint-Vallier est
> Bureau 401
> Qu�bec (Qu�bec)
> Canada G1K 3P6
> Yahoo fax/voice-mail: 1-507-262-1145
>
> -----Original Message-----
> From: sudhi [mailto:[EMAIL PROTECTED]]
> Sent: 17 avril, 2000 12:39
> To: [EMAIL PROTECTED]
> Subject: Session Fail over/Migration
>
> Hello,
> I have question :-)
> I am using apache1.3.12 and apacheJserv 1.1 and ApacheJSSI 1.1.2.
> I am interested in Session Fail over/migration. I looked into all of the
> document and mailing list. I wasn't able to find anything for failure
> and migration. The only thing i was able to find was in the document - "
> How to : Scalability - Load Balancing - Fault tolerance with Apache
> Jserv 1.1 ". In that document, in the fault tolerance section, it
> explains how session failure works (when one Jserv fails the request is
> sent to another Jserv, which creates a new session cookie (which will
> help to associate this request with this Jserv) and erases the old
> cookie. What I am really interested is
> " what happens to the session object ? "
> Is there a way to restore them, if so how to achieve this ?
> Is it possible to achieve session migration (from one jserv to another
> without loosing data) ?
>
> It would be of great help if some body shed some light on this.
> Thanks in advance.
> Sudhi
>
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