KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > com > lutris > appserver > server > sql > DBRowUpdateException


1 /*
2  * Enhydra Java Application Server Project
3  *
4  * The contents of this file are subject to the Enhydra Public License
5  * Version 1.1 (the "License"); you may not use this file except in
6  * compliance with the License. You may obtain a copy of the License on
7  * the Enhydra web site ( http://www.enhydra.org/ ).
8  *
9  * Software distributed under the License is distributed on an "AS IS"
10  * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
11  * the License for the specific terms governing rights and limitations
12  * under the License.
13  *
14  * The Initial Developer of the Enhydra Application Server is Lutris
15  * Technologies, Inc. The Enhydra Application Server and portions created
16  * by Lutris Technologies, Inc. are Copyright Lutris Technologies, Inc.
17  * All Rights Reserved.
18  *
19  * Contributor(s):
20  *
21  * $Id: DBRowUpdateException.java,v 1.1 2004/09/03 13:42:37 sinisa Exp $
22  */
23 package com.lutris.appserver.server.sql;
24
25 /**
26  * DBRowUpdateException is thrown when a CoreDO update fails.
27  *
28  * Two values are used to uniquely identify a row in a table:
29  * oId and version.
30  * The executeUpdate() method creates an SQL UPDATE command
31  * to write the new values in a CoreDO object back to
32  * the correct row in the database.
33  * The row is identifed by the oId and version values specified
34  * in the WHERE-clause of the UPDATE command.
35  *
36  * So, if no row has the specified oId and version combination,
37  * the UPDATE will fail, and report that 0 rows were updated.
38  * Note: other database problems (e.g. disk full) can also cause
39  * an UPDATE to fail, but these are rare.
40  *
41  * When versioning == true, the executeUpdate() method will increment
42  * the version number in both the CoreDO object and in the updated row.
43  *
44  * When the same oId/version combination is used twice to create
45  * two CoreDO objects (A and B) that refer to the same row,
46  * it is possible for the version number of one of those objects
47  * to become out-of-sync with the row in the database.
48  * Object A is updated, and the version number in object A and
49  * in the row is incremented.
50  * When an attempt is made to update object B, the version number in
51  * object B no longer matches the row in the database,
52  * so the row is not found, and the update has no effect
53  * (zero rows are updated).
54  * In this case, the CoreDO.executeUpdate() method throws
55  * a DBRowUpdateException describing the problem.
56  *
57  * The application code that catches this exception
58  * should probably reload the Data Object from the database.
59  *
60  * @version $Revision: 1.1 $
61  * @see CoreDO
62  * @author Jay Gunter
63  */
64 public class DBRowUpdateException extends java.sql.SQLException JavaDoc {
65
66     /**
67      * Construct a exception without a specified cause.
68      *
69      * @param msg The message associated with the exception.
70      */
71     public DBRowUpdateException(String JavaDoc msg) {
72         super(msg);
73     }
74 }
75
Popular Tags