JstlCoreWhen


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  import com.caucho.xml.QName;
34  
35  import java.io.IOException  ;
36  
37  /**
38   * Special generator for a JSTL c:when tag.
39   */
40  public class JstlCoreWhen extends JstlNode {
41    private static final QName TEST = new QName("test");
42    
43    private String   _test;
44    private JspAttribute _testAttr;
45    
46    /**
47     * Adds an attribute.
48     */
49    public void addAttribute(QName name, String   value)
50      throws JspParseException
51    {
52      if (TEST.equals(name))
53        _test = value;
54      else
55        throw error(L.l("`{0}' is an unknown attribute for <{1}>.",
56                        name.getName(), getTagName()));
57    }
58    
59    /**
60     * Adds an attribute.
61     */
62    public void addAttribute(QName name, JspAttribute value)
63      throws JspParseException
64    {
65      if (TEST.equals(name))
66        _testAttr = value;
67      else
68        throw error(L.l("`{0}' is an unknown jsp:attribute for <{1}>.",
69                        name.getName(), getTagName()));
70    }
71  
72    /**
73     * Returns true if the tag has scripting values.
74     */
75    public boolean hasScripting()
76    {
77      return (super.hasScripting() ||
78          hasScripting(_test) || hasScripting(_testAttr));
79    }
80  
81    /**
82     * Generates the XML text representation for the tag validation.
83     *
84     * @param os write stream to the generated XML.
85     */
86    public void printXml(WriteStream os)
87      throws IOException  
88    {
89      os.print("<c:when test=\"");
90      printXmlText(os, _test);
91      os.print("\">");
92  
93      printXmlChildren(os);
94  
95      os.print("</c:when>");
96    }
97    
98    /**
99     * Generates the code for the c:if tag.
100    */
101   public void generate(JspJavaWriter out)
102     throws Exception  
103   {
104     if (_test == null && _testAttr == null)
105       throw error(L.l("required attribute `test' missing from <{0}>",
106                       getTagName()));
107 
108     String   ifExpr;
109 
110     if (_testAttr != null)
111       ifExpr = _testAttr.generateValue(boolean.class);
112     else
113       ifExpr = generateValue(boolean.class, _test);
114 
115     out.println("if (" + ifExpr + ") {");
116     out.pushDepth();
117     
118     generateChildren(out);
119 
120     out.popDepth();
121     out.println("}");
122   }
123 }
124
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