StoreBid


1   package edu.rice.rubis.servlets;
2   
3   import java.io.IOException  ;
4   import java.sql.Connection  ;
5   import java.sql.PreparedStatement  ;
6   import java.sql.ResultSet  ;
7   
8   import javax.servlet.ServletException  ;
9   import javax.servlet.http.HttpServletRequest  ;
10  import javax.servlet.http.HttpServletResponse  ;
11  
12  /** This servlet records a bid in the database and display
13   * the result of the transaction.
14   * It must be called this way :
15   * <pre>
16   * http://..../StoreBid?itemId=aa&userId=bb&minBid=cc&maxQty=dd&bid=ee&maxBid=ff&qty=gg 
17   *   where: aa is the item id 
18   *          bb is the user id
19   *          cc is the minimum acceptable bid for this item
20   *          dd is the maximum quantity available for this item
21   *          ee is the user bid
22   *          ff is the maximum bid the user wants
23   *          gg is the quantity asked by the user
24   * </pre>
25   * @author <a HREF="mailto:cecchet@rice.edu">Emmanuel Cecchet</a> and <a HREF="mailto:julie.marguerite@inrialpes.fr">Julie Marguerite</a>
26   * @version 1.0
27   */
28  
29  public class StoreBid extends RubisHttpServlet
30  {
31  
32  
33    public int getPoolSize()
34    {
35      return Config.StoreBidPoolSize;
36    }
37  
38  /**
39   * Close both statement and connection.
40   */
41    private void closeConnection(PreparedStatement   stmt, Connection   conn)
42    {
43      try
44      {
45        if (stmt != null)
46          stmt.close(); // close statement
47        if (conn != null)
48          releaseConnection(conn);
49      }
50      catch (Exception   ignore)
51      {
52      }
53    }
54  
55  /**
56   * Display an error message.
57   * @param errorMsg the error message value
58   */
59    private void printError(String   errorMsg, ServletPrinter sp)
60    {
61      sp.printHTMLheader("RUBiS ERROR: StoreBid");
62      sp.printHTML(
63        "<h2>Your request has not been processed due to the following error :</h2><br>");
64      sp.printHTML(errorMsg);
65      sp.printHTMLfooter();
66    }
67  
68    /**
69     * Call the <code>doPost</code> method.
70     *
71     * @param request a <code>HttpServletRequest</code> value
72     * @param response a <code>HttpServletResponse</code> value
73     * @exception IOException if an error occurs
74     * @exception ServletException if an error occurs
75     */
76    public void doGet(HttpServletRequest   request, HttpServletResponse   response)
77      throws IOException  , ServletException  
78    {
79      doPost(request, response);
80    }
81  
82    /**
83     * Store the bid to the database and display resulting message.
84     *
85     * @param request a <code>HttpServletRequest</code> value
86     * @param response a <code>HttpServletResponse</code> value
87     * @exception IOException if an error occurs
88     * @exception ServletException if an error occurs
89     */
90    public void doPost(HttpServletRequest   request, HttpServletResponse   response)
91      throws IOException  , ServletException  
92    {
93      Integer   userId; // item id
94      Integer   itemId; // user id
95      float minBid; // minimum acceptable bid for this item
96      float bid; // user bid
97      float maxBid; // maximum bid the user wants
98      int maxQty; // maximum quantity available for this item
99      int qty; // quantity asked by the user
100     ServletPrinter sp = null;
101     PreparedStatement   stmt = null;
102     Connection   conn = null;
103 
104     sp = new ServletPrinter(response, "StoreBid");
105 
106     /* Get and check all parameters */
107 
108     String   value = request.getParameter("userId");
109     if ((value == null) || (value.equals("")))
110     {
111       printError("<h3>You must provide a user identifier !<br></h3>", sp);
112       return;
113     }
114     else
115       userId = new Integer  (value);
116 
117     value = request.getParameter("itemId");
118     if ((value == null) || (value.equals("")))
119     {
120       printError("<h3>You must provide an item identifier !<br></h3>", sp);
121       return;
122     }
123     else
124       itemId = new Integer  (value);
125 
126     value = request.getParameter("minBid");
127     if ((value == null) || (value.equals("")))
128     {
129       printError("<h3>You must provide a minimum bid !<br></h3>", sp);
130       return;
131     }
132     else
133     {
134       Float   foo = new Float  (value);
135       minBid = foo.floatValue();
136     }
137 
138     value = request.getParameter("bid");
139     if ((value == null) || (value.equals("")))
140     {
141       printError("<h3>You must provide a bid !<br></h3>", sp);
142       return;
143     }
144     else
145     {
146       Float   foo = new Float  (value);
147       bid = foo.floatValue();
148     }
149 
150     value = request.getParameter("maxBid");
151     if ((value == null) || (value.equals("")))
152     {
153       printError("<h3>You must provide a maximum bid !<br></h3>", sp);
154       return;
155     }
156     else
157     {
158       Float   foo = new Float  (value);
159       maxBid = foo.floatValue();
160     }
161 
162     value = request.getParameter("maxQty");
163     if ((value == null) || (value.equals("")))
164     {
165       printError("<h3>You must provide a maximum quantity !<br></h3>", sp);
166       return;
167     }
168     else
169     {
170       Integer   foo = new Integer  (value);
171       maxQty = foo.intValue();
172     }
173 
174     value = request.getParameter("qty");
175     if ((value == null) || (value.equals("")))
176     {
177       printError("<h3>You must provide a quantity !<br></h3>", sp);
178       return;
179     }
180     else
181     {
182       Integer   foo = new Integer  (value);
183       qty = foo.intValue();
184     }
185 
186     /* Check for invalid values */
187 
188     if (qty > maxQty)
189     {
190       printError(
191         "<h3>You cannot request "
192           + qty
193           + " items because only "
194           + maxQty
195           + " are proposed !<br></h3>", sp);
196       return;
197     }
198     if (bid < minBid)
199     {
200       printError(
201         "<h3>Your bid of $"
202           + bid
203           + " is not acceptable because it is below the $"
204           + minBid
205           + " minimum bid !<br></h3>", sp);
206       return;
207     }
208     if (maxBid < minBid)
209     {
210       printError(
211         "<h3>Your maximum bid of $"
212           + maxBid
213           + " is not acceptable because it is below the $"
214           + minBid
215           + " minimum bid !<br></h3>", sp);
216       return;
217     }
218     if (maxBid < bid)
219     {
220       printError(
221         "<h3>Your maximum bid of $"
222           + maxBid
223           + " is not acceptable because it is below your current bid of $"
224           + bid
225           + " !<br></h3>", sp);
226       return;
227     }
228     try
229     {
230       conn = getConnection();
231       conn.setAutoCommit(false);
232       String   now = TimeManagement.currentDateToString();
233       stmt =
234         conn.prepareStatement(
235           "INSERT INTO bids VALUES (NULL, \""
236             + userId
237             + "\", \""
238             + itemId
239             + "\", \""
240             + qty
241             + "\", \""
242             + bid
243             + "\", \""
244             + maxBid
245             + "\", \""
246             + now
247             + "\")");
248       stmt.executeUpdate();
249       stmt.close();
250       // update the number of bids and the max bid for the item
251       PreparedStatement   update = null;
252       try
253       {
254         stmt =
255           conn.prepareStatement(
256             "SELECT nb_of_bids, max_bid FROM items WHERE id=?");
257         stmt.setInt(1, itemId.intValue());
258         ResultSet   rs = stmt.executeQuery();
259         if (rs.first())
260         {
261           
262           int nbOfBids = rs.getInt("nb_of_bids");
263           nbOfBids++;
264           float oldMaxBid = rs.getFloat("max_bid");
265           if (bid > oldMaxBid)
266           {
267             oldMaxBid = bid;
268             update =
269               conn.prepareStatement(
270                 "UPDATE items SET max_bid=?, nb_of_bids=? WHERE id=?");
271             update.setFloat(1, maxBid);
272             update.setInt(2, nbOfBids);
273             update.setInt(3, itemId.intValue());
274             update.executeUpdate();
275             update.close();
276           }
277           else
278           {
279             update =
280               conn.prepareStatement("UPDATE items SET nb_of_bids=? WHERE id=?");
281             update.setInt(1, nbOfBids);
282             update.setInt(2, itemId.intValue());
283             update.executeUpdate();
284             update.close();
285           }
286 
287         }
288         else
289         {
290           conn.rollback();
291           printError("Couldn't find the item.", sp);
292           closeConnection(stmt, conn);
293           return;
294         }
295       }
296       catch (Exception   ex)
297       {
298         conn.rollback();
299         printError("Failed to update nb of bids and max bid: " + ex, sp);
300         if (update != null) 
301           update.close();
302         closeConnection(stmt, conn);
303         return;
304       }
305       sp.printHTMLheader("RUBiS: Bidding result");
306       sp.printHTML(
307         "<center><h2>Your bid has been successfully processed.</h2></center>\n");
308       conn.commit();
309       closeConnection(stmt, conn);
310     }
311     catch (Exception   e)
312     {
313       sp.printHTML(
314         "Error while storing the bid (got exception: " + e + ")<br>");
315       try
316       {
317         conn.rollback();
318         closeConnection(stmt, conn);
319       }
320       catch (Exception   se)
321       {
322         printError("Transaction rollback failed: " + e, sp);
323       }
324       return;
325     }
326     sp.printHTMLfooter();
327   }
328 
329   /**
330   * Clean up the connection pool.
331   */
332   public void destroy()
333   {
334     super.destroy();
335   }
336 
337 }
338
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags