/*

 *

 * 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.sql.*;

import javax.sql.*;

import java.util.*;

import javax.ejb.*;

import javax.naming.*;



public class AccountEJB implements EntityBean {



    private String id;

    private String firstName;

    private String lastName;

    private double balance;

    private EntityContext context;

    private Connection con;

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



    public void debit(double amount) 

       throws InsufficientBalanceException {



       if (balance - amount < 0) {

           throw new InsufficientBalanceException();

       }

       balance -= amount;

    }



    public void credit(double amount) {



       balance += amount;

    }

 

    public String getFirstName() {

 

       return firstName;

    }

 

    public String getLastName() {

 

       return lastName;

    }

  

    public double getBalance() {



       return balance;

    }



    public String ejbCreate(String id, String firstName, 

       String lastName, double balance)

       throws CreateException {



       if (balance < 0.00) {

          throw new CreateException

             ("A negative initial balance is not allowed.");

       }



       try {

          insertRow(id, firstName, lastName, balance);

       } catch (Exception ex) {

           throw new EJBException("ejbCreate: " + 

              ex.getMessage());

       }



       this.id = id;

       this.firstName = firstName;

       this.lastName = lastName;

       this.balance = balance;



       return id;

    }



   public String ejbFindByPrimaryKey(String primaryKey) 

      throws FinderException {



      boolean result;



      try {

         result = selectByPrimaryKey(primaryKey);

       } catch (Exception ex) {

           throw new EJBException("ejbFindByPrimaryKey: " + 

              ex.getMessage());

       }

      if (result) {

         return primaryKey;

      }

      else {

         throw new ObjectNotFoundException

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

      }

   }



   public Collection ejbFindByLastName(String lastName)

      throws FinderException {



      Collection result;



      try {

         result = selectByLastName(lastName);

       } catch (Exception ex) {

           throw new EJBException("ejbFindByLastName " + 

              ex.getMessage());

       }



      if (result.isEmpty()) {

         throw new ObjectNotFoundException("No rows found.");

      }

      else {

         return result;

      }

   }



   public Collection ejbFindInRange(double low, double high)

      throws FinderException {



      Collection result;



      try {

         result = selectInRange(low, high);

            

       } catch (Exception ex) {

           throw new EJBException("ejbFindInRange: " + 

              ex.getMessage());

       }

      if (result.isEmpty()) {

         throw new ObjectNotFoundException("No rows found.");

      }

      else {

         return result;

      }

   }



   public void ejbRemove() {



      try {

         deleteRow(id);

       } catch (Exception ex) {

           throw new EJBException("ejbRemove: " + 

              ex.getMessage());

       }

   } 



   public void setEntityContext(EntityContext context) {



      this.context = context;

      try {

         makeConnection();

      } catch (Exception ex) {

          throw new EJBException("Unable to connect to database. " +

             ex.getMessage());

      }

   }



   public void unsetEntityContext() {



      try {

         con.close();

      } catch (SQLException ex) {

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

      }

   }



   public void ejbActivate() {



      id = (String)context.getPrimaryKey();

   }



   public void ejbPassivate() {



      id = null;

   }



   public void ejbLoad() {



      try {

         loadRow();

       } catch (Exception ex) {

           throw new EJBException("ejbLoad: " + 

              ex.getMessage());

       }

   }

   

   public void ejbStore() {



      try {

         storeRow();

       } catch (Exception ex) {

           throw new EJBException("ejbLoad: " + 

              ex.getMessage());

       }

   }





   public void ejbPostCreate(String id, String firstName, 

      String lastName, double balance) { }





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



   private void makeConnection() throws NamingException, SQLException {



      InitialContext ic = new InitialContext();

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

      con =  ds.getConnection();

   }



   private void insertRow (String id, String firstName, String lastName, 

                           double balance) throws SQLException {



          String insertStatement =

                "insert into account values ( ? , ? , ? , ? )";

          PreparedStatement prepStmt = 

                con.prepareStatement(insertStatement);



          prepStmt.setString(1, id);

          prepStmt.setString(2, firstName);

          prepStmt.setString(3, lastName);

          prepStmt.setDouble(4, balance);



          prepStmt.executeUpdate();

          prepStmt.close();

   }



   private void deleteRow(String id) throws SQLException {



      String deleteStatement =

            "delete from account where id = ? ";

      PreparedStatement prepStmt =

            con.prepareStatement(deleteStatement);



      prepStmt.setString(1, id);

      prepStmt.executeUpdate();

      prepStmt.close();

   }



   private boolean selectByPrimaryKey(String primaryKey) 

      throws SQLException {



      String selectStatement =

            "select id " +

            "from account where id = ? ";

      PreparedStatement prepStmt =

            con.prepareStatement(selectStatement);

      prepStmt.setString(1, primaryKey);



      ResultSet rs = prepStmt.executeQuery();

      boolean result = rs.next();

      prepStmt.close();

      return result;

   }



   private Collection selectByLastName(String lastName) 

      throws SQLException {



      String selectStatement =

            "select id " +

            "from account where lastname = ? ";

      PreparedStatement prepStmt = 

            con.prepareStatement(selectStatement);



      prepStmt.setString(1, lastName);

      ResultSet rs = prepStmt.executeQuery();

      ArrayList a = new ArrayList();



      while (rs.next()) {

         String id = rs.getString(1);

         a.add(id);

      }



      prepStmt.close();

      return a;

   }



   private Collection selectInRange(double low, double high) 

      throws SQLException {



      String selectStatement =

            "select id from account " +

            "where balance between  ? and ?";

      PreparedStatement prepStmt = 

            con.prepareStatement(selectStatement);



      prepStmt.setDouble(1, low);

      prepStmt.setDouble(2, high);

      ResultSet rs = prepStmt.executeQuery();

      ArrayList a = new ArrayList();



      while (rs.next()) {

         String id = rs.getString(1);

         a.add(id);

      }



      prepStmt.close();

      return a;

   }



   private void loadRow() throws SQLException {



      String selectStatement =

            "select firstname, lastname, balance " +

            "from account where id = ? ";

      PreparedStatement prepStmt = 

            con.prepareStatement(selectStatement);



      prepStmt.setString(1, this.id);



      ResultSet rs = prepStmt.executeQuery();



      if (rs.next()) {

         this.firstName = rs.getString(1);

         this.lastName = rs.getString(2);

         this.balance = rs.getDouble(3);

         prepStmt.close();

      }

      else {

         prepStmt.close();

         throw new NoSuchEntityException("Row for id " + id +

            " not found in database.");

      }

   }





   private void storeRow() throws SQLException {



      String updateStatement =

            "update account set firstname =  ? ," +

            "lastname = ? , balance = ? " +

            "where id = ?";

      PreparedStatement prepStmt = 

            con.prepareStatement(updateStatement);



      prepStmt.setString(1, firstName);

      prepStmt.setString(2, lastName);

      prepStmt.setDouble(3, balance);

      prepStmt.setString(4, id);

      int rowCount = prepStmt.executeUpdate();

      prepStmt.close();



      if (rowCount == 0) {

         throw new EJBException("Storing row for id " + id + " failed.");

      }

   }



} // AccountEJB