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Java > Open Source Codes > com > caucho > servlets > ssi > ConcatExpr


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  *
23  * Free Software Foundation, Inc.
24  * 59 Temple Place, Suite 330
25  * Boston, MA 02111-1307 USA
26  *
27  * @author Scott Ferguson
28  */
29
30 package com.caucho.servlets.ssi;
31
32 import javax.servlet.http.HttpServletRequest JavaDoc;
33 import javax.servlet.http.HttpServletResponse JavaDoc;
34
35 /**
36  * Represents a SSI string concat expression
37  */
38 public class ConcatExpr extends SSIExpr {
39   private final SSIExpr _left;
40   private final SSIExpr _right;
41
42   private ConcatExpr(SSIExpr left, SSIExpr right)
43   {
44     _left = left;
45     _right = right;
46   }
47
48   static SSIExpr create(SSIExpr left, SSIExpr right)
49   {
50     if (left == null)
51       return right;
52     else if (right == null)
53       return left;
54     else
55       return new ConcatExpr(left, right);
56   }
57
58   /**
59    * Evaluate as a string.
60    */
61   public String JavaDoc evalString(HttpServletRequest JavaDoc request,
62                HttpServletResponse JavaDoc response)
63   {
64     return (_left.evalString(request, response) +
65         _right.evalString(request, response));
66   }
67 }
68
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