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


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
33 import java.sql.SQLException JavaDoc;
34 import java.util.ArrayList JavaDoc;
35 import java.util.logging.Logger JavaDoc;
36
37 class StringExpr extends Expr {
38   private static final Logger JavaDoc log = Log.open(StringExpr.class);
39
40   private String JavaDoc _value;
41
42   StringExpr(String JavaDoc value)
43   {
44     _value = value;
45   }
46
47   /**
48    * Returns the value.
49    */
50   public String JavaDoc getValue()
51   {
52     return _value;
53   }
54
55   /**
56    * Returns the type of the expression.
57    */
58   public Class JavaDoc getType()
59   {
60     return String JavaDoc.class;
61   }
62
63   /**
64    * Returns the cost based on the given FromList.
65    */
66   public long subCost(ArrayList JavaDoc<FromItem> fromList)
67   {
68     return 0;
69   }
70
71   /**
72    * Returns true if the literal is null.
73    */
74   public boolean isNull(QueryContext context)
75     throws SQLException JavaDoc
76   {
77     return _value == null;
78   }
79
80   /**
81    * Evaluates the literal as a string.
82    */
83   public String JavaDoc evalString(QueryContext context)
84     throws SQLException JavaDoc
85   {
86     return _value;
87   }
88
89   public String JavaDoc toString()
90   {
91     return "'" + _value + "'";
92   }
93 }
94
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