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Java > Open Source Codes > com > caucho > jstl > el > XmlWhenTag


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.jstl.el;
30
31 import com.caucho.jsp.PageContextImpl;
32 import com.caucho.jstl.ChooseTag;
33 import com.caucho.util.L10N;
34 import com.caucho.xpath.Env;
35 import com.caucho.xpath.Expr;
36 import com.caucho.xpath.XPath;
37
38 import org.w3c.dom.Node JavaDoc;
39
40 import javax.servlet.jsp.JspException JavaDoc;
41 import javax.servlet.jsp.tagext.Tag JavaDoc;
42 import javax.servlet.jsp.tagext.TagSupport JavaDoc;
43
44 /**
45  * Tag representing an "when" condition.
46  */
47 public class XmlWhenTag extends TagSupport JavaDoc {
48   private static L10N L = new L10N(XmlWhenTag.class);
49   
50   private Expr _select;
51
52   /**
53    * Sets the select expression.
54    *
55    * @param select the select expression.
56    */
57   public void setSelect(Expr select)
58   {
59     _select = select;
60   }
61
62   /**
63    * Process the tag.
64    */
65   public int doStartTag()
66     throws JspException JavaDoc
67   {
68     try {
69       Tag parent = getParent();
70
71       if (! (parent instanceof ChooseTag))
72         throw new JspException JavaDoc(L.l("x:when tag must be contained in a c:choose tag."));
73
74       ChooseTag chooseTag = (ChooseTag) parent;
75
76       if (chooseTag.isMatch())
77         return SKIP_BODY;
78
79       PageContextImpl pageContext = (PageContextImpl) this.pageContext;
80
81       Env env = XPath.createEnv();
82       env.setVarEnv(pageContext.getVarEnv());
83       
84       Node JavaDoc node = pageContext.getNodeEnv();
85       
86       boolean test = _select.evalBoolean(node, env);
87
88       env.free();
89
90       if (test) {
91         chooseTag.setMatch();
92       
93         return EVAL_BODY_INCLUDE;
94       }
95       else
96         return SKIP_BODY;
97     } catch (JspException JavaDoc e) {
98       throw e;
99     } catch (Exception JavaDoc e) {
100       throw new JspException JavaDoc(e);
101     }
102   }
103 }
104
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