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1   /*
2    * $Source$
3    * $Revision$
4    *
5    * Copyright (C) 2000 William Chesters
6    *
7    * Part of Melati (http://melati.org), a framework for the rapid
8    * development of clean, maintainable web applications.
9    *
10   * Melati is free software; Permission is granted to copy, distribute
11   * and/or modify this software under the terms either:
12   *
13   * a) the GNU General Public License as published by the Free Software
14   *    Foundation; either version 2 of the License, or (at your option)
15   *    any later version,
16   *
17   *    or
18   *
19   * b) any version of the Melati Software License, as published
20   *    at http://melati.org
21   *
22   * You should have received a copy of the GNU General Public License and
23   * the Melati Software License along with this program;
24   * if not, write to the Free Software Foundation, Inc.,
25   * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the
26   * GNU General Public License and visit http://melati.org to obtain the
27   * Melati Software License.
28   *
29   * Feel free to contact the Developers of Melati (http://melati.org),
30   * if you would like to work out a different arrangement than the options
31   * outlined here.  It is our intention to allow Melati to be used by as
32   * wide an audience as possible.
33   *
34   * This program is distributed in the hope that it will be useful,
35   * but WITHOUT ANY WARRANTY; without even the implied warranty of
36   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
37   * GNU General Public License for more details.
38   *
39   * Contact details for copyright holder:
40   *
41   *     William Chesters <williamc At paneris.org>
42   *     http://paneris.org/~williamc
43   *     Obrechtstraat 114, 2517VX Den Haag, The Netherlands
44   */
45  
46  package org.melati.poem;
47  
48  /**
49   * A cached instance of an SQL <code>count</code> query.
50   */
51  public class CachedCount extends CachedQuery <Integer> {
52  
53    /**
54     * Constructor.
55     * @param table the table of which we are a count
56     * @param whereClause discriminator, may be null
57     * @param otherTables other tables involved in whereClause, if any
58     */
59    public CachedCount(final Table<?> table,
60                         final String whereClause,
61                         final Table<?> otherTables[]) {
62      super(table, table.countSQL(whereClause), otherTables);
63    }
64  
65    /**
66     * Create a count from a Persistent.
67     *
68     * @param criteria the Persistent representing the query
69     * @param includeDeleted whether to include records marked as deleted
70     * @param excludeUnselectable Whether to append unselectable exclusion SQL 
71     */
72    public CachedCount(final Persistent criteria,
73                       boolean includeDeleted, boolean excludeUnselectable) {
74      super(criteria.getTable(),
75            ((JdbcPersistent)criteria).countMatchSQL(includeDeleted, excludeUnselectable),
76            null);
77    }
78  
79    /**
80     * Constructor where whereClause does not involve other tables.
81     * @param table the table to count
82     * @param whereClause discrimination, can be null
83     */
84    public CachedCount(final Table<?> table, final String whereClause) {
85      this(table, whereClause, null);
86    }
87  
88    /**
89     * @return the count itself
90     */
91    public int count() {
92      compute();
93      return ((Integer)this.rows.elementAt(0)).intValue();
94    }
95  
96  }