/*
* VAMSAS Project
* 
* Dec 15, 2006  
*
*/
 
package uk.ac.vamsas.client.simpleclient;

import java.io.File;
import java.io.IOException;

import uk.ac.vamsas.client.SessionHandle;

/**
 * Class to deal with sessions
 * 
 * retrieves list of available sessions
 * 
 * adds an active session
 * 
 * removes a close session (the last client has been closed)
 * 
 * 
 */
public class SimpleSessionManager
{
  private SessionsFile sessionFile = null;


  protected SimpleSessionManager(File sessionsFile) throws IOException 
  {
    this.initManagerObjects(sessionsFile);
  }

/**
 * construct SessionFile objects and watchers for each
 */
private void initManagerObjects(File sessionsFile) throws IOException 
  {
    if (this.sessionFile!=null )
      throw new IOException("initFactoryObjects called for initialised ClientFactory object.");
    this.sessionFile = new SessionsFile(sessionsFile);
  }


/**
 * make a new watcher object for the sessionsFile
 * @return new SessionsFile watcher instance
 */
public FileWatcher getSessionsWatcher() {
  return new FileWatcher(this.getSessionFile().sessionFile);
}

/**
 * @see uk.ac.vamsas.client.IClientFactory#getCurrentSessions()
 */
public String[] getCurrentSessions() 
{ 
  String[] sessions = null;
  if (this.sessionFile!=null )
    {
      SessionHandle[] sessionHandles =  this.sessionFile.retrieveSessionsList();
      if (sessionHandles != null)
        {
          sessions = new String[sessionHandles.length];
          for (int i = sessionHandles.length -1; i > -1; i--)
            {
              SessionHandle sessionHandle = sessionHandles[i];
              sessions [i] = sessionHandle.getSessionUrn();
            }
        }
    }
  return sessions;
}

/**
 * adds SessionHandle me to the sessionList 
 * @param newSession session to add to the session list
 * @return session index in list or 0 if lock was invalid or addSession operation failed.
 */
public int addSession(SessionHandle newSession) 
  {
    return this.sessionFile.addSession(newSession, false,this.getSessionsWatcher().getChangedState());
  }

/**
 * @return the sessionFile
 */
private SessionsFile getSessionFile()
  {
    return this.sessionFile;
  }

/**
 * Removes a session from the list of  currently active session
 * 
 * @param session SessionHandle of the session to remove
 */
protected void removeSession(SessionHandle session)
  {
      this.getSessionFile().removeSession(session,this.getSessionsWatcher().getChangedState());
  }
}