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Java > Open Source Codes > com > caucho > db > fun > NowExpr


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.fun;
30
31 import com.caucho.db.sql.Expr;
32 import com.caucho.db.sql.FunExpr;
33 import com.caucho.db.sql.QueryContext;
34 import com.caucho.log.Log;
35 import com.caucho.util.Alarm;
36 import com.caucho.util.L10N;
37 import com.caucho.util.QDate;
38
39 import java.sql.SQLException JavaDoc;
40 import java.util.Date JavaDoc;
41 import java.util.logging.Logger JavaDoc;
42
43 public class NowExpr extends FunExpr {
44   protected static final L10N L = new L10N(NowExpr.class);
45   private static final Logger JavaDoc log = Log.open(NowExpr.class);
46
47   protected void addArg(Expr expr)
48     throws SQLException JavaDoc
49   {
50     throw new SQLException JavaDoc(L.l("now() has no arguments"));
51   }
52
53   /**
54    * Returns the expected result type of the expression.
55    */
56   public Class JavaDoc getType()
57   {
58     return Date.class;
59   }
60
61   /**
62    * Returns true for a null value.
63    *
64    * @param rows the current tuple being evaluated
65    *
66    * @return true if null
67    */
68   public boolean isNull(QueryContext context)
69     throws SQLException JavaDoc
70   {
71     return false;
72   }
73
74   /**
75    * Evaluates the expression as a double.
76    *
77    * @param rows the current tuple being evaluated
78    *
79    * @return the double value
80    */
81   public double evalDouble(QueryContext context)
82     throws SQLException JavaDoc
83   {
84     return evalLong(context);
85   }
86
87   /**
88    * Evaluates the expression as a long.
89    *
90    * @param rows the current tuple being evaluated
91    *
92    * @return the long value
93    */
94   public long evalLong(QueryContext context)
95     throws SQLException JavaDoc
96   {
97     return Alarm.getCurrentTime();
98   }
99
100   /**
101    * Evaluates the expression as a string.
102    *
103    * @param rows the current tuple being evaluated
104    *
105    * @return the string value
106    */
107   public String JavaDoc evalString(QueryContext context)
108     throws SQLException JavaDoc
109   {
110     return QDate.formatLocal(evalLong(context));
111   }
112 }
113
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