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Java > Open Source Codes > com > caucho > amber > field > MaxGenerator


1 /*
2  * Copyright (c) 1998-2006 Caucho Technology -- all rights reserved
3  *
4  * This file is part of Resin(R) Open Source
5  *
6  * Each copy or derived work must preserve the copyright notice and this
7  * notice unmodified.
8  *
9  * Resin Open Source is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * Resin Open Source is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17  * of NON-INFRINGEMENT. See the GNU General Public License for more
18  * details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with Resin Open Source; if not, write to the
22  * Free Software Foundation, Inc.
23  * 59 Temple Place, Suite 330
24  * Boston, MA 02111-1307 USA
25  *
26  * @author Scott Ferguson
27  */
28
29 package com.caucho.amber.field;
30
31 import java.sql.Connection JavaDoc;
32 import java.sql.ResultSet JavaDoc;
33 import java.sql.SQLException JavaDoc;
34 import java.sql.Statement JavaDoc;
35
36 /**
37  * Configuration for a bean's field
38  */
39 public class MaxGenerator extends Generator {
40   private String JavaDoc _table;
41   private String JavaDoc _column;
42
43   private String JavaDoc _sql;
44
45   /**
46    * Sets the table.
47    */
48   public void setTable(String JavaDoc table)
49   {
50     _table = table;
51   }
52
53   /**
54    * Sets the column.
55    */
56   public void setColumn(String JavaDoc column)
57   {
58     _column = column;
59   }
60
61   /**
62    * initialize the sql.
63    */
64   public void init()
65   {
66     _sql = "SELECT MAX(" + _column + ") FROM " + _table;
67   }
68   
69   /**
70    * Generates the new id.
71    */
72   public long generate(Connection JavaDoc conn)
73     throws SQLException JavaDoc
74   {
75     Statement JavaDoc stmt = conn.createStatement();
76
77     try {
78       ResultSet JavaDoc rs = stmt.executeQuery(_sql);
79
80       rs.next();
81
82       long value = rs.getLong(1);
83
84       rs.close();
85
86       return value;
87     } finally {
88       stmt.close();
89     }
90   }
91 }
92
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