/*
 * JBoss, the OpenSource EJB server
 *
 * Distributable under LGPL license.
 * See terms of license at gnu.org.
 */
package org.jboss.ejb.plugins;

import java.beans.Beans;
import java.beans.beancontext.BeanContextServicesSupport;
import java.io.File;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.FileOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.lang.reflect.Method;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.lang.reflect.InvocationTargetException;
import java.rmi.RemoteException;
import java.rmi.NoSuchObjectException;
import java.rmi.ServerException;
import java.util.Collection;
import java.util.ArrayList;
import java.util.Iterator;
import java.sql.SQLException;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.PreparedStatement;
import java.sql.Connection;

import javax.ejb.EJBObject;
import javax.ejb.Handle;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;
import javax.ejb.CreateException;
import javax.ejb.DuplicateKeyException;
import javax.ejb.FinderException;
import javax.ejb.RemoveException;
import javax.ejb.EJBException;
import javax.naming.Context;
import javax.naming.InitialContext;

import org.jboss.ejb.Container;
import org.jboss.ejb.StatefulSessionContainer;
import org.jboss.ejb.StatefulSessionPersistenceManager;
import org.jboss.ejb.StatefulSessionEnterpriseContext;
import org.jboss.logging.Logger;


/**
 *  StatefulSessionFilePersistenceManager
 *
 *  This class is one of the passivating plugins for JBoss.  
 *  It is fairly simple and can work from the file system from wich JBoss is operating
 *      
 *  @see <related>
 *  @author Rickard Öberg (rickard.oberg@telkel.com)
 *  @author <a href="marc.fleury@telkel.com">Marc Fleury</a>
 *  @author <a href="mailto:sebastien.alborini@m4x.org">Sebastien Alborini</a>
 *  @version $Revision: 1.18.4.1 $
 */
public class StatefulSessionFilePersistenceManager
   implements StatefulSessionPersistenceManager
{
   static Logger log = Logger.getLogger(StatefulSessionFilePersistenceManager.class);
   // Constants -----------------------------------------------------

   // Attributes ----------------------------------------------------
   private StatefulSessionContainer con;

   private Method ejbActivate;
   private Method ejbPassivate;
   private Method ejbRemove;

   private File dir;

   private ArrayList fields;

   // Static --------------------------------------------------------
   private static long id = System.currentTimeMillis();

   // Constructors --------------------------------------------------

   // Public --------------------------------------------------------
   public void setContainer(Container c)
   {
      con = (StatefulSessionContainer)c;
   }

   public void init()
   throws Exception
   {

      // Find methods
      ejbActivate = SessionBean.class.getMethod("ejbActivate", new Class[0]);

      ejbPassivate = SessionBean.class.getMethod("ejbPassivate", new Class[0]);

      ejbRemove = SessionBean.class.getMethod("ejbRemove", new Class[0]);

      // Initialize the dataStore
      String ejbName = con.getBeanMetaData().getEjbName();

      // Base dir
      File databaseDir = new File(getClass().getResource("/db.properties").getFile()).getParentFile();

      File database = new File(databaseDir, "sessions");
      dir = new File(database, ejbName);
      dir.mkdirs();
      log.debug("Storing sessions for "+ejbName+" in:"+dir);

      // Clear dir of old files
      File[] sessions = dir.listFiles();
      for (int i = 0; i < sessions.length; i++)
      {
         sessions[i].delete();
      }
      log.debug(sessions.length + " old sessions removed");

      // Get fields of class
      Class beanClass = con.getBeanClass();
      fields = new ArrayList();
      while (!beanClass.equals(Object.class))
      {
         Field[] f = beanClass.getDeclaredFields();

         // Skip transient fields
         for (int i = 0; i < f.length; i++)
            if (!Modifier.isTransient(f[i].getModifiers()))
            {
               fields.add(f[i]);
            }

         beanClass = beanClass.getSuperclass();
      }         
   }

   public void start()
   throws Exception
   {
   }

   public void stop()
   {
   }

   public void destroy()
   {
   }

   public void createSession(Method m, Object[] args, StatefulSessionEnterpriseContext ctx)
   throws Exception
   {

      // Set id
      ctx.setId(nextId());

      // Get methods
      try
      {
         Method createMethod = con.getBeanClass().getMethod("ejbCreate", m.getParameterTypes());

         // Call ejbCreate
         createMethod.invoke(ctx.getInstance(), args);

      } catch (IllegalAccessException e)
      {
         // Clear id
         ctx.setId(null);

         // Throw this as a bean exception...(?)
         throw new EJBException(e);
      } catch (InvocationTargetException ite)
      {
         // Clear id
         ctx.setId(null);

         Throwable e = ite.getTargetException();
         if (e instanceof EJBException)
         {
            // Rethrow exception
            throw (EJBException)e;
         }
         else if (e instanceof RuntimeException)
         {
            // Wrap runtime exceptions
            throw new EJBException((Exception)e);
         }
         else if (e instanceof Exception)
         {
            // Remote, Create, or custom app. exception
            throw (Exception)e;
         }
         else
         {
            throw (Error)e;
         }
      }

      // Insert in cache
      ((StatefulSessionContainer)con).getInstanceCache().insert(ctx);

      // Create EJBObject
      if (con.getContainerInvoker() != null)
         ctx.setEJBObject(con.getContainerInvoker().getStatefulSessionEJBObject(ctx.getId()));
      // Create EJBLocalObject
      if (con.getLocalHomeClass() != null)
         ctx.setEJBLocalObject(con.getLocalContainerInvoker().getStatefulSessionEJBLocalObject(ctx.getId()));
   }

   public void activateSession(StatefulSessionEnterpriseContext ctx)
   throws RemoteException
   {
      try
      {
         ObjectInputStream in;


         // Load state
         in = new SessionObjectInputStream(ctx, new FileInputStream(getFile(ctx.getId())));
         
         ctx.setInstance(in.readObject());
         
         in.close();
		 
		 removePassivated(ctx.getId());
         
         // Call bean
         ejbActivate.invoke(ctx.getInstance(), new Object[0]);
		 
      } catch (ClassNotFoundException e)
      {
         throw new ServerException("Could not activate", e); 
      } catch (IOException e)
      {
         throw new ServerException("Could not activate", e); 
      } catch (IllegalAccessException e)
      {
         // Throw this as a bean exception...(?)
         throw new EJBException(e);
      } catch (InvocationTargetException ite)
      {
         Throwable e = ite.getTargetException();
         if (e instanceof EJBException)
         {
            // Rethrow exception
            throw (EJBException)e;
         }
         else if (e instanceof RuntimeException)
         {
            // Wrap runtime exceptions
            throw new EJBException((Exception)e);
         }
         else if (e instanceof RemoteException)
         {
            // Remote, Create, or custom app. exception
            throw (RemoteException)e;
         }
         else
         {
            throw (Error)e;
         }
      }
   }

   public void passivateSession(StatefulSessionEnterpriseContext ctx)
   throws RemoteException
   {
      try
      {
         // Call bean
         ejbPassivate.invoke(ctx.getInstance(), new Object[0]);

         // Store state
         ObjectOutputStream out = new SessionObjectOutputStream(new FileOutputStream(getFile(ctx.getId())));

         out.writeObject(ctx.getInstance());

         out.close();   
         
      } catch (IOException e)
      {
         throw new ServerException("Could not passivate", e);
      }catch (IllegalAccessException e)
      {
         // Throw this as a bean exception...(?)
         throw new EJBException(e);
      } catch (InvocationTargetException ite)
      {
         Throwable e = ite.getTargetException();
         if (e instanceof EJBException)
         {
            // Rethrow exception
            throw (EJBException)e;
         }
         else if (e instanceof RuntimeException)
         {
            // Wrap runtime exceptions
            throw new EJBException((Exception)e);
         }
         else if (e instanceof RemoteException)
         {
            // Remote, Create, or custom app. exception
            throw (RemoteException)e;
         }
         else
         {
            throw (Error)e;
         }
      }
   }

   public void removeSession(StatefulSessionEnterpriseContext ctx)
   throws RemoteException, RemoveException
   {
      // Call bean
      try
      {
         ejbRemove.invoke(ctx.getInstance(), new Object[0]);
		 
      } catch (IllegalAccessException e)
      {
         // Throw this as a bean exception...(?)
         throw new EJBException(e);
      } catch (InvocationTargetException ite)
      {
         Throwable e = ite.getTargetException();
         if (e instanceof EJBException)
         {
            // Rethrow exception
            throw (EJBException)e;
         }
         else if (e instanceof RuntimeException)
         {
            // Wrap runtime exceptions
            throw new EJBException((Exception)e);
         }
         else if (e instanceof RemoveException)
         {
            throw (RemoveException)e;
         }
         else if (e instanceof RemoteException)
         {
            throw (RemoteException)e;
         }
         else
         {
            throw (Error)e;
         }
      }
   }
   
   public void removePassivated(Object key) 
   {
	   // OK also if the file does not exists
	   getFile(key).delete();
   }

   // Z implementation ----------------------------------------------

   // Package protected ---------------------------------------------

   // Protected -----------------------------------------------------
   protected Long nextId()
   {
      return new Long(id++);
   }
   
   protected File getFile(Object key) 
   {
	   return new File(dir, key + ".ser");
   }

   // Private -------------------------------------------------------

   // Inner classes -------------------------------------------------
}


