package org.eclipse.jetty.server.session;
   
   import java.io.DataOutputStream;
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.FileNotFoundException;
   import java.io.FileOutputStream;
   import java.io.IOException;
   import java.io.ObjectOutputStream;
  import java.io.OutputStream;
  import java.util.Enumeration;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.eclipse.jetty.util.IO;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  
  public class HashedSession extends AbstractSession
  {
      private static final Logger LOG = Log.getLogger(HashedSession.class);
  
      private final HashSessionManager _hashSessionManager;
  
      /** Whether the session has been saved because it has been deemed idle; 
       * in which case its attribute map will have been saved and cleared. */
      private transient boolean _idled = false;
  
      /** Whether there has already been an attempt to save this session
       * which has failed.  If there has, there will be no more save attempts
       * for this session.  This is to stop the logs being flooded with errors
       * due to serialization failures that are most likely caused by user
       * data stored in the session that is not serializable. */
      private transient boolean _saveFailed = false;
  
      /* ------------------------------------------------------------- */
      protected HashedSession(HashSessionManager hashSessionManager, HttpServletRequest request)
      {
          super(hashSessionManager,request);
          _hashSessionManager = hashSessionManager;
      }
  
      /* ------------------------------------------------------------- */
      protected HashedSession(HashSessionManager hashSessionManager, long created, long accessed, String clusterId)
      {
          super(hashSessionManager,created, accessed, clusterId);
          _hashSessionManager = hashSessionManager;
      }
  
      /* ------------------------------------------------------------- */
      protected void checkValid()
      {
          if (_hashSessionManager._idleSavePeriodMs!=0)
              deIdle();
          super.checkValid();
      }
      
      /* ------------------------------------------------------------- */
      @Override
      public void setMaxInactiveInterval(int secs)
      {
          super.setMaxInactiveInterval(secs);
          if (getMaxInactiveInterval()>0&&(getMaxInactiveInterval()*1000/10)<_hashSessionManager._scavengePeriodMs)
              _hashSessionManager.setScavengePeriod((secs+9)/10);
      }
  
      /* ------------------------------------------------------------ */
      @Override
      protected void doInvalidate()
      throws IllegalStateException
      {
          super.doInvalidate();
          
          // Remove from the disk
          if (_hashSessionManager._storeDir!=null && getId()!=null)
          {
              String id=getId();
              File f = new File(_hashSessionManager._storeDir, id);
              f.delete();
          }
      }
  
      /* ------------------------------------------------------------ */
      synchronized void save(boolean reactivate)
      {
          // Only idle the session if not already idled and no previous save/idle has failed
          if (!isIdled() && !_saveFailed)
          {
              if (LOG.isDebugEnabled())
                  LOG.debug("Saving {} {}",super.getId(),reactivate);
  
              File file = null;
              FileOutputStream fos = null;
              
              try
              {
                  file = new File(_hashSessionManager._storeDir, super.getId());
  
                  if (file.exists())
                     file.delete();
                 file.createNewFile();
                 fos = new FileOutputStream(file);
                 willPassivate();
                 save(fos);
                 if (reactivate)
                     didActivate();
                 else
                     clearAttributes();
             }
             catch (Exception e)
             {
                 saveFailed(); // We won't try again for this session
 
                 LOG.warn("Problem saving session " + super.getId(), e);
 
                 if (fos != null)
                 {
                     // Must not leave the file open if the saving failed
                     IO.close(fos);
                     // No point keeping the file if we didn't save the whole session
                     file.delete();
                     _idled=false; // assume problem was before _values.clear();
                 }
             }
         }
     }
     /* ------------------------------------------------------------ */
     public synchronized void save(OutputStream os)  throws IOException 
     {
         DataOutputStream out = new DataOutputStream(os);
         out.writeUTF(getClusterId());
         out.writeUTF(getNodeId());
         out.writeLong(getCreationTime());
         out.writeLong(getAccessed());
         
         /* Don't write these out, as they don't make sense to store because they
          * either they cannot be true or their value will be restored in the 
          * Session constructor.
          */
         //out.writeBoolean(_invalid);
         //out.writeBoolean(_doInvalidate);
         //out.writeLong(_maxIdleMs);
         //out.writeBoolean( _newSession);
         out.writeInt(getRequests());
         out.writeInt(getAttributes());
         ObjectOutputStream oos = new ObjectOutputStream(out);
         Enumeration<String> e=getAttributeNames();
         while(e.hasMoreElements())
         {
             String key=e.nextElement();
             oos.writeUTF(key);
             oos.writeObject(doGet(key));
         }
         oos.close();
     }
 
     /* ------------------------------------------------------------ */
     public synchronized void deIdle()
     {
         if (isIdled())
         {
             // Access now to prevent race with idling period
             access(System.currentTimeMillis());
 
             if (LOG.isDebugEnabled())
                 LOG.debug("Deidling " + super.getId());
 
             FileInputStream fis = null;
 
             try
             {
                 File file = new File(_hashSessionManager._storeDir, super.getId());
                 if (!file.exists() || !file.canRead())
                     throw new FileNotFoundException(file.getName());
 
                 fis = new FileInputStream(file);
                 _idled = false;
                 _hashSessionManager.restoreSession(fis, this);
 
                 didActivate();
                 
                 // If we are doing period saves, then there is no point deleting at this point 
                 if (_hashSessionManager._savePeriodMs == 0)
                     file.delete();
             }
             catch (Exception e)
             {
                 LOG.warn("Problem deidling session " + super.getId(), e);
                 IO.close(fis);
                 invalidate();
             }
         }
     }
 
     
     /* ------------------------------------------------------------ */
     /**
      * Idle the session to reduce session memory footprint.
      * 
      * The session is idled by persisting it, then clearing the session values attribute map and finally setting 
      * it to an idled state.  
      */
     public synchronized void idle()
     {
         save(false);
     }
     
     /* ------------------------------------------------------------ */
     public synchronized boolean isIdled()
     {
       return _idled;
     }
 
     /* ------------------------------------------------------------ */
     public synchronized boolean isSaveFailed()
     {
         return _saveFailed;
     }
 
     /* ------------------------------------------------------------ */
     public synchronized void saveFailed()
     {
         _saveFailed = true;
     }
 
 }