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


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.log.Log;
32 import com.caucho.util.L10N;
33
34 import java.sql.SQLException JavaDoc;
35 import java.util.logging.Logger JavaDoc;
36
37 /**
38  * Represents a GROUP BY expression.
39  */
40 public class GroupResultExpr extends Expr implements GroupExpr {
41   protected static final L10N L = new L10N(GroupResultExpr.class);
42   private static final Logger JavaDoc log = Log.open(GroupResultExpr.class);
43
44   private static final int LONG_VALUE = 1;
45   private static final int DOUBLE_VALUE = 2;
46   private static final int STRING_VALUE = 3;
47     
48   private Expr _expr;
49   private int _index;
50   private int _type;
51
52   GroupResultExpr(int index, Expr expr)
53   {
54     _index = index;
55     _expr = expr;
56
57     if (expr instanceof GroupResultExpr)
58       Thread.dumpStack();
59
60     if (_expr.isLong())
61       _type = LONG_VALUE;
62     else if (_expr.isDouble())
63       _type = DOUBLE_VALUE;
64     else
65       _type = STRING_VALUE;
66   }
67
68   /**
69    * Returns any name.
70    */
71   public String JavaDoc getName()
72   {
73     return _expr.getName();
74   }
75   
76   protected Expr bind(Query query)
77     throws SQLException JavaDoc
78   {
79     _expr = _expr.bind(query);
80
81     return this;
82   }
83
84   /**
85    * Evaluates aggregate functions during the group phase.
86    *
87    * @param context the current database tuple
88    */
89   public void evalGroup(QueryContext context)
90     throws SQLException JavaDoc
91   {
92     if (_expr.isNull(context))
93       return;
94
95     switch (_type) {
96     default:
97       {
98     String JavaDoc value = _expr.evalString(context);
99     
100     context.setGroupString(_index, value);
101       }
102       break;
103     }
104   }
105
106   public String JavaDoc evalString(QueryContext context)
107   {
108     return context.getGroupString(_index);
109   }
110
111   public String JavaDoc toString()
112   {
113     return "GroupResult[" + _expr + "]";
114   }
115 }
116
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