KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > com > caucho > db > sql > AutoIncrementExpr


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 SoftwareFoundation, Inc.
23  * 59 Temple Place, Suite 330
24  * Boston, MA 02111-1307 USA
25  *
26  * @author Scott Ferguson
27  */
28
29 package com.caucho.db.sql;
30
31 import com.caucho.db.jdbc.GeneratedKeysResultSet;
32 import com.caucho.db.table.Column;
33 import com.caucho.db.table.Table;
34 import com.caucho.log.Log;
35
36 import java.sql.SQLException JavaDoc;
37 import java.util.logging.Logger JavaDoc;
38
39 class AutoIncrementExpr extends Expr {
40   private static final Logger JavaDoc log = Log.open(AutoIncrementExpr.class);
41
42   private Table _table;
43
44   AutoIncrementExpr(Table table)
45   {
46     _table = table;
47   }
48
49   /**
50    * Returns the type of the expression.
51    */
52   public Class JavaDoc getType()
53   {
54     return long.class;
55   }
56
57   /**
58    * Evaluates the expression as a long
59    *
60    * @param row the current data tuple
61    *
62    * @return the long value
63    */
64   public long evalLong(QueryContext context)
65     throws SQLException JavaDoc
66   {
67     long value = _table.nextAutoIncrement(context);
68
69     GeneratedKeysResultSet keysRS = context.getGeneratedKeysResultSet();
70
71     if (keysRS != null) {
72       Column column = _table.getAutoIncrementColumn();
73
74       keysRS.setColumn(1, column);
75       keysRS.setLong(1, value);
76     }
77
78     return value;
79   }
80
81   /**
82    * Evaluates the expression as a double
83    *
84    * @param row the current data tuple
85    *
86    * @return the double value
87    */
88   public double evalDouble(QueryContext context)
89     throws SQLException JavaDoc
90   {
91     return evalLong(context);
92   }
93
94   /**
95    * Evaluates the expression as a string
96    *
97    * @param row the current data tuple
98    *
99    * @return the string value
100    */
101   public String JavaDoc evalString(QueryContext context)
102     throws SQLException JavaDoc
103   {
104     return String.valueOf(evalLong(context));
105   }
106
107   public String JavaDoc toString()
108   {
109     return "auto_increment()";
110   }
111 }
112
Popular Tags