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Java > Open Source Codes > com > caucho > amber > expr > fun > SubstringFunExpr


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 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.expr.fun;
30
31 import com.caucho.amber.expr.AmberExpr;
32 import com.caucho.amber.query.QueryParser;
33 import com.caucho.util.CharBuffer;
34 import com.caucho.util.L10N;
35
36 import java.util.ArrayList JavaDoc;
37
38
39 /**
40  * SUBSTRING function expression
41  */
42 public class SubstringFunExpr extends FunExpr {
43   private static final L10N L = new L10N(SubstringFunExpr.class);
44
45   /**
46    * Creates a new expression
47    */
48   protected SubstringFunExpr(QueryParser parser,
49                              ArrayList JavaDoc<AmberExpr> args)
50   {
51     super(parser, "substring", args, false);
52   }
53
54   public static FunExpr create(QueryParser parser,
55                                ArrayList JavaDoc<AmberExpr> args)
56   {
57     return new SubstringFunExpr(parser, args);
58   }
59
60   /**
61    * Generates the where expression.
62    */
63   public void generateWhere(CharBuffer cb)
64   {
65     generateInternalWhere(cb, true);
66   }
67
68   /**
69    * Generates the (update) where expression.
70    */
71   public void generateUpdateWhere(CharBuffer cb)
72   {
73     generateInternalWhere(cb, false);
74   }
75
76   //
77 // private/protected
78
79   void generateInternalWhere(CharBuffer cb,
80                              boolean select)
81   {
82     ArrayList JavaDoc<AmberExpr> args = getArgs();
83
84     int n = args.size();
85
86     // XXX: this validation should be moved to QueryParser
87 // if (n != 3)
88 // throw new QueryParseException(L.l("expected 3 arguments for SUBSTRING"));
89
90     // XXX: MySQL requires 'substring' but Derby requires 'substr' and
91 // Postgres accepts both.
92 cb.append("substr(");
93
94     if (select)
95       args.get(0).generateWhere(cb);
96     else
97       args.get(0).generateUpdateWhere(cb);
98
99     cb.append(", ");
100
101     if (select)
102       args.get(1).generateWhere(cb);
103     else
104       args.get(1).generateUpdateWhere(cb);
105
106     cb.append(", ");
107
108     if (select)
109       args.get(2).generateWhere(cb);
110     else
111       args.get(2).generateUpdateWhere(cb);
112
113     cb.append(")");
114   }
115 }
116
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