package tim.dao;

import java.sql.*;
import javax.naming.*;
import javax.sql.*;


/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2007</p>
 * <p>Company: </p>
 * @author not attributable
 * @version 1.0
 */

public abstract class BaseDao {


  protected DataSource ds;
  protected InitialContext ctx;
  protected String DATASOURCE = "jdbc/mnpDS";

 /**
  * Inizializza il data source
  * @throws Exception
  */
 protected void initDB() throws Exception{
     try
     {
         ctx = new InitialContext();
         ds = (DataSource)ctx.lookup(DATASOURCE);
     }
     catch (Exception ex)
     {
         ex.printStackTrace();
         throw ex;
     }
     finally
     {
         try
         {
           ctx.close();
         }
         catch (Exception ex) {}
     }
 }

  /**
  * Metodo per ottenere le connessioni dal DB
  * Se non è disponibile una connessione ritorna null
  */
   public Connection getConnection() throws Exception{
     Connection conn = null;
     try
     {
         if (ds==null) initDB();
         conn = ds.getConnection();

     }
     catch (Exception ex)
     {
         ex.printStackTrace();
         throw ex;
     }
     finally
     {
         try
         {
            if( conn != null ) conn.setAutoCommit(false);
         }
         catch (Exception ex)
         {
           ex.printStackTrace();
           throw ex;
         }
     }
     // se non riesce ad ottenere una connessione per tre volte torna null
     return conn;

 }


   /**
    * Metodo per la chiusura del ResultSet,dello Statement e della Connection
    * tale metodo non lancia eccezzioni
    * @param rs
    * @param stmt
    * @param c
    */
   public void closeAll(ResultSet rs, Statement stmt, Connection c) {
       try
       {
           if(rs!=null) rs.close();
       }
       catch (Throwable ex) {}
       try
       {
           if(stmt!=null) stmt.close();
       }
       catch (Throwable ex) {}
       try
       {
           if(c!=null)
             c.close();
       }
       catch (Throwable ex) {}
   }

}