/*

 *

 * 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 WidgetEJB implements EntityBean {



   private String widgetId;

   private String description;

   private double price;

   private EntityContext context;

   private Connection con;

   private String logicalDBName = "java:comp/env/jdbc/WidgetDB";



   

   public String getDescription() {



      return description;

   }



   public double getPrice() {



      return price;

   }



   public String ejbCreate(String widgetId, String description, 

      double price)

      throws CreateException {



      try {

         insertRow(widgetId, description, price);

      } catch (Exception ex) {

          throw new EJBException("ejbCreate: " + 

             ex.getMessage());

      }



      this.widgetId = widgetId;

      this.description = description;

      this.price = price;



      return widgetId;

    }



   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 void ejbRemove() {



      try {

         deleteRow(widgetId);

       } 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() {



      widgetId = (String)context.getPrimaryKey();

   }



   public void ejbPassivate() {



      widgetId = 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 widgetId, String description, 

      double price) { }





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



   private void makeConnection() throws NamingException, SQLException {



      InitialContext ic = new InitialContext();

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

      con =  ds.getConnection();

   }



   private void insertRow (String widgetId, String description, 

                           double price) throws SQLException {



          String insertStatement =

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

          PreparedStatement prepStmt = 

                con.prepareStatement(insertStatement);



          prepStmt.setString(1, widgetId);

          prepStmt.setString(2, description);

          prepStmt.setDouble(3, price);



          prepStmt.executeUpdate();

          prepStmt.close();

   }



   private void deleteRow(String widgetId) throws SQLException {



      String deleteStatement =

            "delete from widget where widgetid = ? ";

      PreparedStatement prepStmt =

            con.prepareStatement(deleteStatement);



      prepStmt.setString(1, widgetId);

      prepStmt.executeUpdate();

      prepStmt.close();

   }



   private boolean selectByPrimaryKey(String primaryKey) 

      throws SQLException {



      String selectStatement =

            "select widgetid " +

            "from widget where widgetid = ? ";

      PreparedStatement prepStmt =

            con.prepareStatement(selectStatement);

      prepStmt.setString(1, primaryKey);



      ResultSet rs = prepStmt.executeQuery();

      boolean result = rs.next();

      prepStmt.close();

      return result;

   }



   private void loadRow() throws SQLException {



      String selectStatement =

            "select description, price " +

            "from widget where widgetid = ? ";

      PreparedStatement prepStmt = 

            con.prepareStatement(selectStatement);



      prepStmt.setString(1, this.widgetId);



      ResultSet rs = prepStmt.executeQuery();



      if (rs.next()) {

         this.description = rs.getString(1);

         this.price = rs.getDouble(2);

         prepStmt.close();

      }

      else {

         prepStmt.close();

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

            " not found in database.");

      }

   }





   private void storeRow() throws SQLException {



      String updateStatement =

            "update widget set description =  ? , " +

            "price = ? " +

            "where widgetid = ?";

      PreparedStatement prepStmt = 

            con.prepareStatement(updateStatement);



      prepStmt.setString(1, description);

      prepStmt.setDouble(2, price);

      prepStmt.setString(3, widgetId);

      int rowCount = prepStmt.executeUpdate();

      prepStmt.close();



      if (rowCount == 0) {

         throw new EJBException("Storing row for widgetId " + 

            widgetId + " failed.");

      }

   }



} // WidgetEJB