/*

 *

 * Copyright 2000 Sun Microsystems, Inc. All Rights Reserved.

 * 

 * This software is the proprietary information of Sun Microsystems, Inc.  

 * Use is subject to license terms.

 * 

 */



import java.util.*;

import javax.ejb.*;

import java.sql.*;

import javax.sql.*;

import javax.naming.*;



public class BankEJB implements SessionBean, SessionSynchronization {



   private String customerId;

   private double checkingBalance;

   private double savingBalance;

   private SessionContext context;

   private Connection con;

   private String dbName = "java:comp/env/jdbc/BankDB";



   public void transferToSaving(double amount) throws 

      InsufficientBalanceException  {



      checkingBalance -= amount;

      savingBalance += amount;



      try {

         updateChecking(checkingBalance);

         if (checkingBalance < 0.00) {

            context.setRollbackOnly();

            throw new InsufficientBalanceException();

         }

         updateSaving(savingBalance);

      } catch (SQLException ex) {

          throw new EJBException 

             ("Transaction failed due to SQLException: " 

             + ex.getMessage());

      }

   }



   public double getCheckingBalance() {



      return checkingBalance;

   }



   public double getSavingBalance() {



      return savingBalance;

   }



   public void ejbCreate(String id) throws CreateException {



      customerId = id;



      try {

         makeConnection();

         checkingBalance = selectChecking();

         savingBalance = selectSaving();

      } catch (Exception ex) {

          throw new CreateException(ex.getMessage());

      }

     

   }





   public void ejbRemove() {



      try {

          con.close();

      } catch (SQLException ex) {

          throw new EJBException("ejbRemove SQLException: " + ex.getMessage());

      }

   }



   public void ejbActivate() {



      try {

         makeConnection();

      } catch (Exception ex) {

          throw new EJBException("ejbActivate Exception: " + ex.getMessage());

      }

   }



   public void ejbPassivate() {



      try {

        con.close();

      } catch (SQLException ex) {

          throw new EJBException("ejbPassivate Exception: " + ex.getMessage());

      }

   }





   public void setSessionContext(SessionContext context) {

      this.context = context;

   }



   public void afterBegin() {



      System.out.println("afterBegin()");

      try {

         checkingBalance = selectChecking();

         savingBalance = selectSaving();

      } catch (SQLException ex) {

          throw new EJBException("afterBegin Exception: " + ex.getMessage());

      }

         

   }



   public void beforeCompletion() {



      System.out.println("beforeCompletion()");

   }



   public void afterCompletion(boolean committed) {



      System.out.println("afterCompletion: " + committed);

      if (committed == false) {

         try {

            checkingBalance = selectChecking();

            savingBalance = selectSaving();

         } catch (SQLException ex) {

             throw new EJBException("afterCompletion SQLException: " +

                ex.getMessage());

         }

      }

   }



   public BankEJB() {}



/************************** Database Routines **********************/



   private void updateChecking(double amount) throws SQLException {



      String updateStatement =

            "update checking set balance =  ? " +

            "where id = ?";



      PreparedStatement prepStmt = 

            con.prepareStatement(updateStatement);



      prepStmt.setDouble(1, amount);

      prepStmt.setString(2, customerId);

      prepStmt.executeUpdate();

      prepStmt.close();

   }



   private void updateSaving(double amount) throws SQLException {



      String updateStatement =

            "update saving set balance =  ? " +

            "where id = ?";



      PreparedStatement prepStmt =

            con.prepareStatement(updateStatement);



      prepStmt.setDouble(1, amount);

      prepStmt.setString(2, customerId);

      prepStmt.executeUpdate();

      prepStmt.close();

   }



   private double selectChecking() throws SQLException {



      String selectStatement =

            "select balance " +

            "from checking where id = ? ";

      PreparedStatement prepStmt =

            con.prepareStatement(selectStatement);



      prepStmt.setString(1, customerId);



      ResultSet rs = prepStmt.executeQuery();



      if (rs.next()) {

         double result = rs.getDouble(1);

         prepStmt.close();

         return result;

      }

      else {

         prepStmt.close();

         throw new EJBException

            ("Row for id " + customerId + " not found.");

      } 

   }





   private double selectSaving() throws SQLException {



      String selectStatement =

            "select balance " +

            "from saving where id = ? ";

      PreparedStatement prepStmt =

            con.prepareStatement(selectStatement);



      prepStmt.setString(1, customerId);



      ResultSet rs = prepStmt.executeQuery();



      if (rs.next()) {

         double result = rs.getDouble(1);

         prepStmt.close();

         return result;

      }

      else {

         prepStmt.close();

         throw new EJBException

            ("Row for id " + customerId + " not found.");

      } 

   }



   private void makeConnection() 

      throws NamingException, SQLException {



      InitialContext ic = new InitialContext();

      DataSource ds = (DataSource) ic.lookup(dbName);

      con =  ds.getConnection();

   }



} // BankEJB