package edu.rice.rubis.beans;

import java.rmi.RemoteException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Collection;
import java.util.GregorianCalendar;
import java.util.LinkedList;

import javax.ejb.CreateException;
import javax.ejb.EJBException;
import javax.ejb.EntityBean;
import javax.ejb.EntityContext;
import javax.ejb.FinderException;
import javax.ejb.RemoveException;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;
import javax.sql.DataSource;

/**
 * ItemBean is an entity bean with "bean managed persistence".
 * The state of an instance is stored into a relational database.
 * The following table should exist:<p>
 * <pre>
 * CREATE TABLE items (
 *    id            INTEGER UNSIGNED NOT NULL UNIQUE,
 *    name          VARCHAR(100),
 *    description   TEXT,
 *    initial_price FLOAT UNSIGNED NOT NULL,
 *    quantity      INTEGER UNSIGNED NOT NULL,
 *    reserve_price FLOAT UNSIGNED DEFAULT 0,
 *    buy_now       FLOAT UNSIGNED DEFAULT 0,
 *    nb_of_bids    INTEGER UNSIGNED DEFAULT 0,
 *    max_bid       FLOAT UNSIGNED DEFAULT 0,
 *    start_date    DATETIME,
 *    end_date      DATETIME,
 *    seller        INTEGER,
 *    category      INTEGER,
 *    PRIMARY KEY(id),
 *    INDEX seller_id (seller),
 *    INDEX category_id (category)
 * );
 * </pre>
 * @author <a href="mailto:cecchet@rice.edu">Emmanuel Cecchet</a> and <a href="mailto:julie.marguerite@inrialpes.fr">Julie Marguerite</a>
 * @version 1.1
 */

public class ItemBean implements EntityBean
{
  private EntityContext entityContext;
  private transient boolean isDirty; // used for the isModified function
  private Context initialContext;
  private DataSource datasource;

  /* Class member variables */

  public Integer id;
  public String name;
  public String description;
  public float initialPrice;
  public int quantity;
  public float reservePrice;
  public float buyNow;
  public int nbOfBids;
  public float maxBid;
  public String startDate;
  public String endDate;
  public Integer sellerId;
  public Integer categoryId;

  /**
   * Get item id.
   *
   * @return item id
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public Integer getId() throws RemoteException
  {
    return id;
  }

  /**
   * Get item name. This description is usually a short description of the item.
   *
   * @return item name
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String getName() throws RemoteException
  {
    return name;
  }

  /**
   * Get item description . This is usually an HTML file describing the item.
   *
   * @return item description
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String getDescription() throws RemoteException
  {
    return description;
  }

  /**
   * Get item initial price set by the seller.
   *
   * @return item initial price
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public float getInitialPrice() throws RemoteException
  {
    return initialPrice;
  }

  /**
   * Get how many of this item are to be sold.
   *
   * @return item quantity
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public int getQuantity() throws RemoteException
  {
    return quantity;
  }

  /**
   * Get item reserve price set by the seller. The seller can refuse to sell if reserve price is not reached.
   *
   * @return item reserve price
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public float getReservePrice() throws RemoteException
  {
    return reservePrice;
  }

  /**
   * Get item Buy Now price set by the seller. A user can directly by the item at this price (no auction).
   *
   * @return item Buy Now price
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public float getBuyNow() throws RemoteException
  {
    return buyNow;
  }

  /**
   * Get item maximum bid (if any) for this item. This value should be the same as doing <pre>SELECT MAX(bid) FROM bids WHERE item_id=?</pre>
   *
   * @return current maximum bid or 0 if no bid
   * @exception RemoteException if an error occurs
   * @since 1.1
   */
  public float getMaxBid() throws RemoteException
  {
    return maxBid;
  }

  /**
   * Get number of bids for this item. This value should be the same as doing <pre>SELECT COUNT(*) FROM bids WHERE item_id=?</pre>
   *
   * @return number of bids
   * @exception RemoteException if an error occurs
   * @since 1.1
   */
  public int getNbOfBids() throws RemoteException
  {
    return nbOfBids;
  }

  /**
   * Start date of the auction in the format 'YYYY-MM-DD hh:mm:ss'
   *
   * @return start date of the auction
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String getStartDate() throws RemoteException
  {
    return startDate;
  }

  /**
   * End date of the auction in the format 'YYYY-MM-DD hh:mm:ss'
   *
   * @return end date of the auction
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String getEndDate() throws RemoteException
  {
    return endDate;
  }

  /**
   * Give the user id of the seller
   *
   * @return seller's user id
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public Integer getSellerId() throws RemoteException
  {
    return sellerId;
  }

  /**
   * Give the category id of the item
   *
   * @return item's category id
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public Integer getCategoryId() throws RemoteException
  {
    return categoryId;
  }

  /**
   * Get the seller's nickname by finding the Bean corresponding
   * to the user. 
   *
   * @return nickname
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String getSellerNickname() throws RemoteException
  {
    Context initialContext = null;
    try
    {
      initialContext = new InitialContext();
    }
    catch (Exception e)
    {
      System.err.print("Cannot get initial context for JNDI: " + e);
      return null;
    }

    // Try to find the user nick name corresponding to the sellerId
    UserHome uHome;
    try
    {
      uHome =
        (UserHome) PortableRemoteObject.narrow(
          initialContext.lookup("UserHome"),
          UserHome.class);
    }
    catch (Exception e)
    {
      System.err.print("Cannot lookup User: " + e);
      return null;
    }
    try
    {
      User u = uHome.findByPrimaryKey(new UserPK(sellerId));
      return u.getNickName();
    }
    catch (Exception e)
    {
      System.err.print(
        "This user does not exist (got exception: " + e + ")<br>");
      return null;
    }
  }

  /**
   * Get the category name by finding the Bean corresponding to the category Id.
   *
   * @return category name
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String getCategoryName() throws RemoteException
  {
    Context initialContext = null;
    try
    {
      initialContext = new InitialContext();
    }
    catch (Exception e)
    {
      System.err.print("Cannot get initial context for JNDI: " + e);
      return null;
    }

    // Try to find the CategoryName corresponding to the categoryId
    CategoryHome cHome;
    try
    {
      cHome =
        (CategoryHome) PortableRemoteObject.narrow(
          initialContext.lookup("CategoryHome"),
          CategoryHome.class);
    }
    catch (Exception e)
    {
      System.err.print("Cannot lookup Category: " + e);
      return null;
    }
    try
    {
      Category c = cHome.findByPrimaryKey(new CategoryPK(id));
      return c.getName();
    }
    catch (Exception e)
    {
      System.err.print(
        "This category does not exist (got exception: " + e + ")<br>");
      return null;
    }
  }

  /**
   * Set a new item name
   *
   * @param newName item name
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setName(String newName) throws RemoteException
  {
    name = newName;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Set a new item description
   *
   * @param newDescription item description
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setDescription(String newDescription) throws RemoteException
  {
    description = newDescription;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Set a new initial price for the item
   *
   * @param newInitialPrice item initial price
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setInitialPrice(float newInitialPrice) throws RemoteException
  {
    initialPrice = newInitialPrice;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Set a new item quantity
   *
   * @param qty item quantity
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setQuantity(int qty) throws RemoteException
  {
    quantity = qty;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Set a new reserve price for the item
   *
   * @param newReservePrice item reserve price
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setReservePrice(float newReservePrice) throws RemoteException
  {
    reservePrice = newReservePrice;
  }

  /**
   * Set a new Buy Now price for the item
   *
   * @param newBuyNow item Buy Now price
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setBuyNow(float newBuyNow) throws RemoteException
  {
    buyNow = newBuyNow;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Set item maximum bid. This function checks if newMaxBid is greater
   * than current maxBid and only updates the value in this case.
   *
   * @param newMaxBid new maximum bid
   * @exception RemoteException if an error occurs
   * @since 1.1
   */
  public void setMaxBid(float newMaxBid) throws RemoteException
  {
    if (newMaxBid > maxBid)
    {
      maxBid = newMaxBid;
      isDirty = true; // the bean content has been modified
    }
  }

  /**
   * Set the number of bids for this item
   *
   * @param newNbOfBids new number of bids
   * @exception RemoteException if an error occurs
   * @since 1.1
   */
  public void setNbOfBids(int newNbOfBids) throws RemoteException
  {
    nbOfBids = newNbOfBids;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Add one bid for this item
   *
   * @exception RemoteException if an error occurs
   * @since 1.1
   */
  public void addOneBid() throws RemoteException
  {
    nbOfBids++;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Set a new beginning date for the auction
   *
   * @param newDate auction new beginning date
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setStartDate(String newDate) throws RemoteException
  {
    startDate = newDate;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Set a new ending date for the auction
   *
   * @param newDate auction new ending date
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setEndDate(String newDate) throws RemoteException
  {
    endDate = newDate;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Set a new seller identifier. This id must match
   * the primary key of the users table.
   *
   * @param id seller id
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setSellerId(Integer id) throws RemoteException
  {
    sellerId = id;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Set a new category identifier. This id must match
   * the primary key of the category table.
   *
   * @param id category id
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public void setCategoryId(Integer id) throws RemoteException
  {
    categoryId = id;
    isDirty = true; // the bean content has been modified
  }

  /**
   * Retrieve a connection..
   *
   * @return connection
   * @exception Exception if an error occurs
   */
  public Connection getConnection() throws Exception
  {
    try
    {
      if (datasource == null)
      {
        // Finds DataSource from JNDI
        initialContext = new InitialContext();
        datasource =
          (DataSource) initialContext.lookup("java:comp/env/jdbc/rubis");
      }
      return datasource.getConnection();
    }
    catch (Exception e)
    {
      throw new Exception("Cannot retrieve the connection.");
    }
  }

  /**
   * This method is used to retrieve an Item Bean from its primary key,
   * that is to say its id.
   *
   * @param id Item id (primary key)
   *
   * @return the Item if found else null
   * @exception FinderException if an error occurs
   * @exception RemoteException if an error occurs
   */
  public ItemPK ejbFindByPrimaryKey(ItemPK id)
    throws FinderException, RemoteException
  {
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      conn = getConnection();
      stmt = conn.prepareStatement("SELECT name FROM items WHERE id=?");
      stmt.setInt(1, id.getId().intValue());
      ResultSet rs = stmt.executeQuery();
      if (!rs.first())
      {
        return null;
      }
      rs.close();
      stmt.close();
      conn.close();
      return id;
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException("Failed to retrieve object item: " + e);
    }
  }

  /**
   * This method is used to retrieve all Item Beans belonging to
   * a seller. You must provide the user id of the seller.
   *
   * @param id User id of the seller
   *
   * @return List of Items primary keys found (eventually empty)
   * @exception RemoteException if an error occurs
   * @exception FinderException if an error occurs
   */
  public Collection ejbFindBySeller(Integer id)
    throws RemoteException, FinderException
  {
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      conn = getConnection();
      stmt = conn.prepareStatement("SELECT id FROM items WHERE seller=?");
      stmt.setInt(1, id.intValue());
      ResultSet rs = stmt.executeQuery();
      LinkedList results = new LinkedList();
      int pk;
      if (rs.first())
      {
        do
        {
          pk = rs.getInt("id");
          results.add(new ItemPK(new Integer(pk)));
        }
        while (rs.next());
      }
      rs.close();
      stmt.close();
      conn.close();
      return results;
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException("Failed to get all items by seller: " + e);
    }
  }

  /**
   * This method is used to retrieve all Item Beans belonging to
   * a specific category. You must provide the category id.
   *
   * @param id Category id
   *
   * @return List of Items primary keys found (eventually empty)
   * @exception RemoteException if an error occurs
   * @exception FinderException if an error occurs
   */
  public Collection ejbFindByCategory(Integer id)
    throws RemoteException, FinderException
  {
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      conn = getConnection();
      stmt = conn.prepareStatement("SELECT id FROM items WHERE category=?");
      stmt.setInt(1, id.intValue());
      ResultSet rs = stmt.executeQuery();
      LinkedList results = new LinkedList();
      int pk;
      if (rs.first())
      {
        do
        {
          pk = rs.getInt("id");
          results.add(new ItemPK(new Integer(pk)));
        }
        while (rs.next());
      }
      rs.close();
      stmt.close();
      conn.close();
      return results;
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException("Failed to get all items by category: " + e);
    }
  }

  /**
   * This method is used to retrieve Item Beans belonging to a specific category
   * that are still to sell (auction end date is not passed).
   * You must provide the category id.
   *
   * @param id Category id
   *
   * @return List of Items primary keys found (eventually empty)
   * @exception RemoteException if an error occurs
   * @exception FinderException if an error occurs
   */
  public Collection ejbFindCurrentByCategory(Integer id)
    throws RemoteException, FinderException
  {
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      conn = getConnection();
      stmt =
        conn.prepareStatement(
          "SELECT id FROM items WHERE where category=? AND end_date>=NOW()");
      stmt.setInt(1, id.intValue());
      ResultSet rs = stmt.executeQuery();
      LinkedList results = new LinkedList();
      int pk;
      if (rs.first())
      {
        do
        {
          pk = rs.getInt("id");
          results.add(new ItemPK(new Integer(pk)));
        }
        while (rs.next());
      }
      rs.close();
      stmt.close();
      conn.close();
      return results;
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException(
        "Failed to get items with ongoing auction by category: " + e);
    }
  }

  /**
   * Get all the items the user is currently selling.
   *
   * @param userId user id
   *
   * @return Vector of items primary keys (can be less than maxToCollect)
   * @exception RemoteException if an error occurs
   * @exception FinderException if an error occurs
   */
  public Collection ejbFindUserCurrentSellings(Integer userId)
    throws RemoteException, FinderException
  {
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      conn = getConnection();
      stmt =
        conn.prepareStatement(
          "SELECT id FROM items WHERE items.seller=? AND items.end_date>=NOW()");
      stmt.setInt(1, userId.intValue());
      ResultSet rs = stmt.executeQuery();
      LinkedList results = new LinkedList();
      Integer pk;
      if (rs.first())
      {
        do
        {
          pk = new Integer(rs.getInt("id"));
          results.add(new ItemPK(pk));
        }
        while (rs.next());
      }
      rs.close();
      stmt.close();
      conn.close();
      return results;
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException(
        "Failed to get items a user is currently selling: " + e);
    }
  }

  /**
   * Get all the items the user sold in the last 30 days.
   *
   * @param userId user id
   *
   * @return Vector of items primary keys (can be less than maxToCollect)
   * @exception RemoteException if an error occurs
   * @exception FinderException if an error occurs
   */
  public Collection ejbFindUserPastSellings(Integer userId)
    throws RemoteException, FinderException
  {
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      conn = getConnection();
      stmt =
        conn.prepareStatement(
          "SELECT id FROM items WHERE items.seller=? AND TO_DAYS(NOW()) - TO_DAYS(items.end_date) <= 30");
      stmt.setInt(1, userId.intValue());
      ResultSet rs = stmt.executeQuery();
      LinkedList results = new LinkedList();
      int pk;
      if (rs.first())
      {
        do
        {
          pk = rs.getInt("id");
          results.add(new ItemPK(new Integer(pk)));
        }
        while (rs.next());
      }
      rs.close();
      stmt.close();
      conn.close();
      return results;
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException(
        "Failed to get items a user sold in the past 30 days: " + e);
    }
  }

  /**
   * This method is used to retrieve all items from the database!
   *
   * @return List of all items primary keys (eventually empty)
   * @exception RemoteException if an error occurs
   * @exception FinderException if an error occurs
   */
  public Collection ejbFindAllItems() throws RemoteException, FinderException
  {
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      conn = getConnection();
      stmt = conn.prepareStatement("SELECT id FROM items");
      ResultSet rs = stmt.executeQuery();
      int pk;
      LinkedList results = new LinkedList();
      if (rs.first())
      {
        do
        {
          pk = rs.getInt("id");
          results.add(new ItemPK(new Integer(pk)));
        }
        while (rs.next());
      }
      rs.close();
      stmt.close();
      conn.close();
      return results;
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException("Failed to get all items: " + e);
    }
  }

  /**
   * This method is used to create a new Item Bean.
   *
   * @param itemName short item designation
   * @param itemDescription long item description, usually an HTML file
   * @param itemInitialPrice initial price fixed by the seller
   * @param itemQuantity number to sell (of this item)
   * @param itemReservePrice reserve price (minimum price the seller really wants to sell)
   * @param itemBuyNow price if a user wants to buy the item immediatly
   * @param duration duration of the auction in days (start date is when the method is called and end date is computed according to the duration)
   * @param itemSellerId seller id, must match the primary key of table users
   * @param itemCategoryId category id, must match the primary key of table categories
   *
   * @return pk primary key set to null
   *
   * @exception CreateException if an error occurs
   * @exception RemoteException if an error occurs
   * @exception RemoveException if an error occurs
   * @since 1.0
   */
  public ItemPK ejbCreate(
    String itemName,
    String itemDescription,
    float itemInitialPrice,
    int itemQuantity,
    float itemReservePrice,
    float itemBuyNow,
    int duration,
    Integer itemSellerId,
    Integer itemCategoryId)
    throws CreateException, RemoteException, RemoveException
  {
    GregorianCalendar start = new GregorianCalendar();
    // Connecting to IDManager Home interface thru JNDI
    IDManagerHome home = null;
    IDManager idManager = null;

    try
    {
      InitialContext initialContext = new InitialContext();
      home =
        (IDManagerHome) PortableRemoteObject.narrow(
          initialContext.lookup("java:comp/env/ejb/IDManager"),
          IDManagerHome.class);
    }
    catch (Exception e)
    {
      throw new EJBException("Cannot lookup IDManager: " + e);
    }
    try
    {
      IDManagerPK idPK = new IDManagerPK();
      idManager = home.findByPrimaryKey(idPK);
      id = idManager.getNextItemID();
      name = itemName;
      description = itemDescription;
      initialPrice = itemInitialPrice;
      quantity = itemQuantity;
      reservePrice = itemReservePrice;
      buyNow = itemBuyNow;
      sellerId = itemSellerId;
      categoryId = itemCategoryId;
      nbOfBids = 0;
      maxBid = 0;
      startDate = TimeManagement.dateToString(start);
      endDate =
        TimeManagement.dateToString(TimeManagement.addDays(start, duration));
    }
    catch (Exception e)
    {
      throw new EJBException("Cannot get a new id for item: " + e);
    }
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      conn = getConnection();
      stmt =
        conn.prepareStatement(
          "INSERT INTO items VALUES ("
            + id.intValue()
            + ", \""
            + name
            + "\", \""
            + description
            + "\", \""
            + initialPrice
            + "\", \""
            + quantity
            + "\", \""
            + reservePrice
            + "\", \""
            + buyNow
            + "\", 0, 0, \""
            + startDate
            + "\", \""
            + endDate
            + "\", "
            + sellerId
            + ", "
            + categoryId
            + ")");
      stmt.executeUpdate();
      stmt.close();
      conn.close();
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException("Failed to create object item: " + e);
    }
    return new ItemPK(id);
  }

  /** This method does currently nothing */
  public void ejbPostCreate(
    String itemName,
    String itemDescription,
    float itemInitialPrice,
    int itemQuantity,
    float itemReservePrice,
    float itemBuyNow,
    int duration,
    Integer itemSellerId,
    Integer itemCategoryId)
  {
  }

  /** Mandatory methods */
  public void ejbActivate() throws RemoteException
  {
  }
  public void ejbPassivate() throws RemoteException
  {
  }

  /**
   * This method delete the record from the database.
   * @exception RemoteException if an error occurs
   * @exception RemoveException if an error occurs
   */
  public void ejbRemove() throws RemoteException, RemoveException
  {
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      conn = getConnection();
      stmt = conn.prepareStatement("DELETE FROM items WHERE id=?");
      stmt.setInt(1, id.intValue());
      stmt.executeUpdate();
      stmt.close();
      conn.close();
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException("Failed to remove object item: " + e);
    }

  }

  /**
   * Update the record.
   * @exception RemoteException if an error occurs
   */
  public void ejbStore() throws RemoteException
  {
    PreparedStatement stmt = null;
    Connection conn = null;
    if (isDirty)
    {
      isDirty = false;
      try
      {
        conn = getConnection();
        stmt =
          conn.prepareStatement(
            "UPDATE items SET name=?, description=?, initial_price=?, quantity=?, reserve_price=?, buy_now=?, nb_of_bids=?, max_bid=?, start_date=?, end_date=?, seller=?, category=? WHERE id=?");
        stmt.setString(1, name);
        stmt.setString(2, description);
        stmt.setFloat(3, initialPrice);
        stmt.setInt(4, quantity);
        stmt.setFloat(5, reservePrice);
        stmt.setFloat(6, buyNow);
        stmt.setInt(7, nbOfBids);
        stmt.setFloat(8, maxBid);
        stmt.setString(9, startDate);
        stmt.setString(10, endDate);
        stmt.setInt(11, sellerId.intValue());
        stmt.setInt(12, categoryId.intValue());
        stmt.setInt(13, id.intValue());
        stmt.executeUpdate();
        stmt.close();
        conn.close();
      }
      catch (Exception e)
      {
        try
        {
          if (stmt != null)
            stmt.close();
          if (conn != null)
            conn.close();
        }
        catch (Exception ignore)
        {
        }
        throw new EJBException("Failed to update object item: " + e);
      }
    }
  }

  /**
   * Read the reccord from the database and update the bean.
   * @exception RemoteException if an error occurs
   */
  public void ejbLoad() throws RemoteException
  {
    isDirty = false;
    PreparedStatement stmt = null;
    Connection conn = null;
    try
    {
      ItemPK pk = (ItemPK) entityContext.getPrimaryKey();
      id = pk.getId();
      conn = getConnection();
      stmt = conn.prepareStatement("SELECT * FROM items WHERE id=?");
      stmt.setInt(1, id.intValue());
      ResultSet rs = stmt.executeQuery();
      if (!rs.first())
      {
        throw new EJBException("Object not found");
      }
      name = rs.getString("name");
      description = rs.getString("description");
      initialPrice = rs.getFloat("initial_price");
      quantity = rs.getInt("quantity");
      reservePrice = rs.getFloat("reserve_price");
      buyNow = rs.getFloat("buy_now");
      nbOfBids = rs.getInt("nb_of_bids");
      maxBid = rs.getFloat("max_bid");
      startDate = rs.getString("start_date");
      endDate = rs.getString("end_date");
      sellerId = new Integer(rs.getInt("seller"));
      categoryId = new Integer(rs.getInt("category"));
      rs.close();
      stmt.close();
      conn.close();
    }
    catch (Exception e)
    {
      try
      {
        if (stmt != null)
          stmt.close();
        if (conn != null)
          conn.close();
      }
      catch (Exception ignore)
      {
      }
      throw new EJBException("Failed to update item bean: " + e);
    }
  }

  /**
   * Sets the associated entity context. The container invokes this method 
   *  on an instance after the instance has been created. 
   * 
   * This method is called in an unspecified transaction context. 
   * 
   * @param context An EntityContext interface for the instance. The instance should 
   *                store the reference to the context in an instance variable. 
   * @exception EJBException  Thrown by the method to indicate a failure 
   *                          caused by a system-level error.
   * @exception RemoteException - This exception is defined in the method signature
   *                           to provide backward compatibility for enterprise beans
   *                           written for the EJB 1.0 specification. 
   *                           Enterprise beans written for the EJB 1.1 and 
   *                           higher specification should throw the javax.ejb.EJBException 
   *                           instead of this exception. 
   */
  public void setEntityContext(EntityContext context) throws RemoteException
  {
    entityContext = context;
  }

  /**
   * Unsets the associated entity context. The container calls this method 
   *  before removing the instance. This is the last method that the container 
   *  invokes on the instance. The Java garbage collector will eventually invoke 
   *  the finalize() method on the instance. 
   *
   * This method is called in an unspecified transaction context. 
   * 
   * @exception EJBException  Thrown by the method to indicate a failure 
   *                          caused by a system-level error.
   * @exception RemoteException - This exception is defined in the method signature
   *                           to provide backward compatibility for enterprise beans
   *                           written for the EJB 1.0 specification. 
   *                           Enterprise beans written for the EJB 1.1 and 
   *                           higher specification should throw the javax.ejb.EJBException 
   *                           instead of this exception.
   */
  public void unsetEntityContext() throws RemoteException
  {
    entityContext = null;
  }

  /**
   * Display item information as an HTML table row
   *
   * @return a <code>String</code> containing HTML code
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String printItem() throws RemoteException
  {
    return "<TR><TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.ViewItem?itemId="
      + id
      + "\">"
      + name
      + "<TD>"
      + maxBid
      + "<TD>"
      + nbOfBids
      + "<TD>"
      + endDate
      + "<TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.PutBidAuth?itemId="
      + id
      + "\"><IMG SRC=\""
      + BeanConfig.context
      + "/bid_now.jpg\" height=22 width=90></a>\n";
  }

  /**
   * Display item information for the AboutMe servlet
   *
   * @param qty an <code>int</code> value
   * @return a <code>String</code> containing HTML code
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String printUserBoughtItem(int qty) throws RemoteException
  {
    return "<TR><TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.ViewItem?itemId="
      + id
      + "\">"
      + name
      + "</a>\n"
      + "<TD>"
      + qty
      + "\n"
      + "<TD>"
      + buyNow
      + "\n"
      + "<TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.ViewUserInfo?userId="
      + sellerId
      + "\">"
      + getSellerNickname()
      + "</a>\n";
  }

  /**
   * Display item information for the AboutMe servlet
   *
   * @param bidMaxBid a <code>float</code> value
   * @return a <code>String</code> containing HTML code (Warning last link must be completed by servlet)
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String printItemUserHasBidOn(float bidMaxBid) throws RemoteException
  {
    return "<TR><TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.ViewItem?itemId="
      + id
      + "\">"
      + name
      + "<TD>"
      + initialPrice
      + "<TD>"
      + maxBid
      + "<TD>"
      + bidMaxBid
      + "<TD>"
      + quantity
      + "<TD>"
      + startDate
      + "<TD>"
      + endDate
      + "<TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.ViewUserInfo?userId="
      + sellerId
      + "\">"
      + getSellerNickname()
      + "<TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.PutBid?itemId="
      + id;
  }

  /**
   * Display item information as an HTML table row
   *
   * @return a <code>String</code> containing HTML code
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String printSell() throws RemoteException
  {
    return "<TR><TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.ViewItem?itemId="
      + id
      + "\">"
      + name
      + "<TD>"
      + initialPrice
      + "<TD>"
      + maxBid
      + "<TD>"
      + quantity
      + "<TD>"
      + reservePrice
      + "<TD>"
      + buyNow
      + "<TD>"
      + startDate
      + "<TD>"
      + endDate
      + "\n";
  }

  /**
   * Display item information for the AboutMe servlet
   *
   * @return a <code>String</code> containing HTML code
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String printUserWonItem() throws RemoteException
  {
    return "<TR><TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.ViewItem?itemId="
      + id
      + "\">"
      + name
      + "</a>\n"
      + "<TD>"
      + maxBid
      + "\n"
      + "<TD><a href=\""
      + BeanConfig.context
      + "/servlet/edu.rice.rubis.beans.servlets.ViewUserInfo?userId="
      + sellerId
      + "\">"
      + getSellerNickname()
      + "</a>\n";
  }

  /**
   * Display item information for the Buy Now servlet
   *
   * @param userId an <code>int</code> value
   * @return a <code>String</code> containing HTML code
   * @exception RemoteException if an error occurs
   * @since 1.0
   */
  public String printItemDescriptionToBuyNow(int userId) throws RemoteException
  {
    String result =
      "<TABLE>\n"
        + "<TR><TD>Quantity<TD><b><BIG>"
        + quantity
        + "</BIG></b>\n"
        + "<TR><TD>Seller<TD><a href=\""
        + BeanConfig.context
        + "/servlet/edu.rice.rubis.beans.servlets.ViewUserInfo?userId="
        + sellerId
        + "\">"
        + getSellerNickname()
        + "</a> (<a href=\""
        + BeanConfig.context
        + "/servlet/edu.rice.rubis.beans.servlets.PutCommentAuth?to="
        + sellerId
        + "&itemId="
        + id
        + "\">Leave a comment on this user</a>)\n"
        + "<TR><TD>Started<TD>"
        + startDate
        + "\n"
        + "<TR><TD>Ends<TD>"
        + endDate
        + "\n"
        + "</TABLE>"
        + "<TABLE width=\"100%\" bgcolor=\"#CCCCFF\">\n"
        + "<TR><TD align=\"center\" width=\"100%\"><FONT size=\"4\" color=\"#000000\"><B>Item description</B></FONT></TD></TR>\n"
        + "</TABLE><p>\n"
        + description
        + "<br><p>\n"
        + "<TABLE width=\"100%\" bgcolor=\"#CCCCFF\">\n"
        + "<TR><TD align=\"center\" width=\"100%\"><FONT size=\"4\" color=\"#000000\"><B>Buy Now</B></FONT></TD></TR>\n"
        + "</TABLE><p>\n"
        + "<form action=\""
        + BeanConfig.context
        + "/servlet/edu.rice.rubis.beans.servlets.StoreBuyNow\" method=POST>\n"
        + "<input type=hidden name=userId value="
        + userId
        + ">\n"
        + "<input type=hidden name=itemId value="
        + id
        + ">\n"
        + "<input type=hidden name=maxQty value="
        + quantity
        + ">\n";
    if (quantity > 1)
      result =
        result
          + "<center><table><tr><td>Quantity:</td>\n"
          + "<td><input type=text size=5 name=qty></td></tr></table></center>\n";
    else
      result = result + "<input type=hidden name=qty value=1>\n";
    result =
      result
        + "</table><p><center><input type=submit value=\"Buy now!\"></center><p>\n";
    return result;
  }
}