01: /*
02: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
03: *
04: * This file is part of Resin(R) Open Source
05: *
06: * Each copy or derived work must preserve the copyright notice and this
07: * notice unmodified.
08: *
09: * 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;
32: import java.sql.ResultSet;
33: import java.sql.SQLException;
34: import java.sql.Statement;
35:
36: /**
37: * Configuration for a bean's field
38: */
39: public class MaxGenerator extends Generator {
40: private String _table;
41: private String _column;
42:
43: private String _sql;
44:
45: /**
46: * Sets the table.
47: */
48: public void setTable(String table) {
49: _table = table;
50: }
51:
52: /**
53: * Sets the column.
54: */
55: public void setColumn(String column) {
56: _column = column;
57: }
58:
59: /**
60: * initialize the sql.
61: */
62: public void init() {
63: _sql = "SELECT MAX(" + _column + ") FROM " + _table;
64: }
65:
66: /**
67: * Generates the new id.
68: */
69: public long generate(Connection conn) throws SQLException {
70: Statement stmt = conn.createStatement();
71:
72: try {
73: ResultSet rs = stmt.executeQuery(_sql);
74:
75: rs.next();
76:
77: long value = rs.getLong(1);
78:
79: rs.close();
80:
81: return value;
82: } finally {
83: stmt.close();
84: }
85: }
86: }
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