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Java > Open Source Codes > com > caucho > jsp > java > JstlCoreChoose


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.jsp.java;
30
31 import com.caucho.jsp.JspParseException;
32 import com.caucho.vfs.WriteStream;
33
34 import java.io.IOException JavaDoc;
35
36 public class JstlCoreChoose extends JstlNode {
37   /**
38    * Children are handled specially.
39    */
40   public void addChild(JspNode node)
41     throws JspParseException
42   {
43     if (node instanceof JstlCoreWhen)
44       super.addChild(node);
45     else if (node instanceof JstlXmlWhen)
46       super.addChild(node);
47     else if (node instanceof JstlCoreOtherwise)
48       super.addChild(node);
49     else
50       throw error(L.l("<{0}> is not allowed as a child of <{1}>. Only <when> and <otherwise> are allowed children.",
51                       node.getTagName(), getTagName()));
52   }
53
54   /**
55    * Whitespace text is ignored.
56    */
57   public JspNode addText(String JavaDoc text)
58     throws JspParseException
59   {
60     if (! isWhitespace(text))
61       throw error(L.l("text is not allowed as a child of <{1}>. Only <c:when> and <c:otherwise> are allowed children.",
62                       getTagName()));
63
64     return null;
65   }
66
67   /**
68    * Validity checking.
69    */
70   public void endElement()
71     throws JspParseException
72   {
73     if (_children == null || _children.size() == 0)
74       throw error(L.l("<{0}> must have at least one <c:when> clause.",
75                       getTagName()));
76   }
77
78   /**
79    * Generates the XML text representation for the tag validation.
80    *
81    * @param os write stream to the generated XML.
82    */
83   public void printXml(WriteStream os)
84     throws IOException JavaDoc
85   {
86     os.print("<c:choose>");
87
88     printXmlChildren(os);
89
90     os.print("</c:choose>");
91   }
92
93   /**
94    * Generates the code for the c:out tag.
95    */
96   public void generate(JspJavaWriter out)
97     throws Exception JavaDoc
98   {
99     for (int i = 0; i < _children.size(); i++) {
100       JspNode node = _children.get(i);
101       
102       if (i != 0)
103         out.print("else ");
104
105       node.generate(out);
106     }
107   }
108 }
109
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