package edu.rice.rubis.servlets;

import java.io.IOException;
import java.sql.Connection;
import java.sql.SQLException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

/** This class is a replacement for RubisHttpServlet that does not provide connection
 * pooling but relies on a datasource (such as the one provided by Tomcat) that
 * provides pooling.
 */
public abstract class RubisHttpServlet2 extends HttpServlet
{
  private DataSource ds = null;

  /** Initialize the datasource */
  public void init() throws ServletException
  {
    try
    {
      Context ctx = new InitialContext();
      if (ctx == null)
        throw new Exception("Boom - No Context");

      ds = (DataSource) ctx.lookup("java:comp/env/jdbc/RUBiS");
    }
    catch (NamingException e)
    {
      e.printStackTrace();
      throw new ServletException(e);
    }
    catch (Exception e)
    {
      e.printStackTrace();
      throw new ServletException(e);
    }
  }

  /**
  * Closes a <code>Connection</code>.
  * @param connection to close 
  */
  public void closeConnection(Connection connection)
  {
    try
    {
      connection.close();
    }
    catch (Exception e)
    {
    }
  }

  /**
   * Gets a connection from the pool (round-robin)
   *
   * @return a <code>Connection</code> or 
   * null if no connection is available
   */
  public synchronized Connection getConnection()
  {
    if (ds != null)
      try
      {
        return ds.getConnection();
      }
      catch (SQLException e)
      {
        e.printStackTrace();
        return null;
      }
    else
    {
      System.out.println("ERROR: No datasource available");
      return null;
    }
  }

  /**
  * Releases a connection to the pool.
  *
  * @param c the connection to release
  */
  public synchronized void releaseConnection(Connection c)
  {
    try
    {
      c.close();
    }
    catch (SQLException e)
    {
      e.printStackTrace();
    }
  }
  public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws IOException, ServletException
  {

  }

  public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws IOException, ServletException
  {

  }

}